problem
stringlengths 16
191
| explanation
stringlengths 6
29k
⌀ | type
stringlengths 3
136
⌀ |
|---|---|---|
What is (are) spastic paraplegia type 7 ? | Spastic paraplegia type 7 is part of a group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the lower limbs (paraplegia). Hereditary spastic paraplegias are divided into two types: pure and complex. The pure types involve the lower limbs. The complex types involve the lower limbs and can also affect the upper limbs to a lesser degree; the structure or functioning of the brain; and the nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). Spastic paraplegia type 7 can occur in either the pure or complex form. Like all hereditary spastic paraplegias, spastic paraplegia type 7 involves spasticity of the leg muscles and increased muscle weakness. People with this form of spastic paraplegia can also experience exaggerated reflexes (hyperreflexia) in the arms; speech difficulties (dysarthria); difficulty swallowing (dysphagia); involuntary movements of the eyes (nystagmus); mild hearing loss; abnormal curvature of the spine (scoliosis); high-arched feet (pes cavus); numbness, tingling, or pain in the arms and legs (sensory neuropathy); disturbance in the nerves used for muscle movement (motor neuropathy); and muscle wasting (amyotrophy). The onset of symptoms varies greatly among those with spastic paraplegia type 7; however, abnormalities in muscle tone and other features are usually noticeable in adulthood. | spastic paraplegia type 7 |
How many people are affected by spastic paraplegia type 7 ? | The prevalence of all hereditary spastic paraplegias combined is estimated to be 2 to 6 in 100,000 people worldwide. Spastic paraplegia type 7 likely accounts for only a small percentage of all spastic paraplegia cases. | spastic paraplegia type 7 |
What are the genetic changes related to spastic paraplegia type 7 ? | Mutations in the SPG7 gene cause spastic paraplegia type 7. The SPG7 gene provides instructions for producing a protein called paraplegin. Located within the inner membrane of the energy-producing centers of cells (mitochondria), paraplegin is one of the proteins that form a complex called the m-AAA protease. The m-AAA protease is responsible for assembling ribosomes (cellular structures that process the cell's genetic instructions to create proteins) and removing nonfunctional proteins in the mitochondria. When there is a mutation in paraplegin, the m-AAA protease cannot function correctly. Nonfunctional m-AAA proteases cause a build up of unusable proteins in the mitochondria of nerve cells, which can result in swelling of the cell, reduced cell signaling, and impaired cell movement, leading to the major signs and symptoms of spastic paraplegia type 7. | spastic paraplegia type 7 |
Is spastic paraplegia type 7 inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | spastic paraplegia type 7 |
What are the treatments for spastic paraplegia type 7 ? | These resources address the diagnosis or management of spastic paraplegia type 7: - Gene Review: Gene Review: Hereditary Spastic Paraplegia Overview - Gene Review: Gene Review: Spastic Paraplegia 7 - Genetic Testing Registry: Spastic paraplegia 7 - Spastic Paraplegia Foundation, Inc.: Treatments and Therapies These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | spastic paraplegia type 7 |
What is (are) Hajdu-Cheney syndrome ? | Hajdu-Cheney syndrome is a rare disorder that can affect many parts of the body, particularly the bones. Loss of bone tissue from the hands and feet (acro-osteolysis) is a characteristic feature of the condition. The fingers and toes are short and broad, and they may become shorter over time as bone at the tips continues to break down. Bone loss in the fingers can interfere with fine motor skills, such as picking up small objects. Bone abnormalities throughout the body are common in Hajdu-Cheney syndrome. Affected individuals develop osteoporosis, which causes the bones to be brittle and prone to fracture. Many affected individuals experience breakage (compression fractures) of the spinal bones (vertebrae). Some also develop abnormal curvature of the spine (scoliosis or kyphosis). Hajdu-Cheney syndrome also affects the shape and strength of the long bones in the arms and legs. The abnormalities associated with this condition lead to short stature. Hajdu-Cheney syndrome also causes abnormalities of the skull bones, including the bones of the face. The shape of the skull is often described as dolichocephalic, which means it is elongated from back to front. In many affected individuals, the bone at the back of the skull bulges outward, causing a bump called a prominent occiput. Distinctive facial features associated with this condition include widely spaced and downward-slanting eyes, eyebrows that grow together in the middle (synophrys), low-set ears, a sunken appearance of the middle of the face (midface hypoplasia), and a large space between the nose and upper lip (a long philtrum). Some affected children are born with an opening in the roof of the mouth called a cleft palate or with a high arched palate. In affected adults, the facial features are often described as "coarse." Other features of Hajdu-Cheney syndrome found in some affected individuals include joint abnormalities, particularly an unusually large range of joint movement (hypermobility); dental problems; hearing loss; a deep, gravelly voice; excess body hair; recurrent infections in childhood; heart defects; and kidney abnormalities such as the growth of multiple fluid-filled cysts (polycystic kidneys). Some people with this condition have delayed development in childhood, but the delays are usually mild. The most serious complications of Hajdu-Cheney syndrome, which occur in about half of all affected individuals, are abnormalities known as platybasia and basilar invagination. Platybasia is a flattening of the base of the skull caused by thinning and softening of the skull bones. Basilar invagination occurs when the softened bones allow part of the spine to protrude abnormally through the opening at the bottom of the skull, pushing into the lower parts of the brain. These abnormalities can lead to severe neurological problems, including headaches, abnormal vision and balance, a buildup of fluid in the brain (hydrocephalus), abnormal breathing, and sudden death. The signs and symptoms of Hajdu-Cheney syndrome vary greatly among affected individuals, even among members of the same family. Many of the disorder's features, such as acro-osteolysis and some of the characteristic facial features, are not present at birth but become apparent in childhood or later. The risk of developing platybasia and basilar invagination also increases over time. The features of Hajdu-Cheney syndrome overlap significantly with those of a condition called serpentine fibula-polycystic kidney syndrome (SFPKS). Although they used to be considered separate disorders, researchers discovered that the two conditions are associated with mutations in the same gene. Based on these similarities, many researchers now consider Hajdu-Cheney syndrome and SFPKS to be variants of the same condition. | Hajdu-Cheney syndrome |
How many people are affected by Hajdu-Cheney syndrome ? | Hajdu-Cheney syndrome is a rare disease; its prevalence is unknown. Fewer than 100 affected individuals have been described in the medical literature. | Hajdu-Cheney syndrome |
What are the genetic changes related to Hajdu-Cheney syndrome ? | Hajdu-Cheney syndrome is associated with mutations in the NOTCH2 gene. This gene provides instructions for making a receptor called Notch2. Receptor proteins have specific sites into which certain other proteins, called ligands, fit like keys into locks. When a ligand binds to the Notch2 receptor, it triggers signals that are important for the normal development and function of many different types of cells. Studies suggest that signaling through the Notch2 receptor is important for the early development of bones and later for bone remodeling, a normal process in which old bone is removed and new bone is created to replace it. Notch2 signaling also appears to be involved in the development of the heart, kidneys, teeth, and other parts of the body. Mutations in a specific area near the end of the NOTCH2 gene are associated with Hajdu-Cheney syndrome. These mutations lead to a version of the Notch2 receptor that cannot be broken down normally. As a result, the receptor continues to be active even after signaling should stop. Researchers are unsure how excessive Notch2 signaling is related to the varied features of Hajdu-Cheney syndrome. They suspect that the skeletal features of the disorder, including acro-osteolysis, osteoporosis, and distinctive facial features, likely result from abnormal bone development and remodeling. Excess signaling through the overactive Notch2 receptor may increase the removal of old bone, reduce the formation of new bone, or both. It is less clear how the overactive receptor contributes to the other signs and symptoms of this condition. | Hajdu-Cheney syndrome |
Is Hajdu-Cheney syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered NOTCH2 gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. Less commonly, an affected person inherits the mutation from one affected parent. | Hajdu-Cheney syndrome |
What are the treatments for Hajdu-Cheney syndrome ? | These resources address the diagnosis or management of Hajdu-Cheney syndrome: - Genetic Testing Registry: Hajdu-Cheney syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Hajdu-Cheney syndrome |
What is (are) triple X syndrome ? | Triple X syndrome, also called trisomy X or 47,XXX, is characterized by the presence of an additional X chromosome in each of a female's cells. Although females with this condition may be taller than average, this chromosomal change typically causes no unusual physical features. Most females with triple X syndrome have normal sexual development and are able to conceive children. Triple X syndrome is associated with an increased risk of learning disabilities and delayed development of speech and language skills. Delayed development of motor skills (such as sitting and walking), weak muscle tone (hypotonia), and behavioral and emotional difficulties are also possible, but these characteristics vary widely among affected girls and women. Seizures or kidney abnormalities occur in about 10 percent of affected females. | triple X syndrome |
How many people are affected by triple X syndrome ? | This condition occurs in about 1 in 1,000 newborn girls. Five to 10 girls with triple X syndrome are born in the United States each day. | triple X syndrome |
What are the genetic changes related to triple X syndrome ? | People normally have 46 chromosomes in each cell. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help determine whether a person will develop male or female sex characteristics. Females typically have two X chromosomes (46,XX), and males have one X chromosome and one Y chromosome (46,XY). Triple X syndrome results from an extra copy of the X chromosome in each of a female's cells. As a result of the extra X chromosome, each cell has a total of 47 chromosomes (47,XXX) instead of the usual 46. An extra copy of the X chromosome is associated with tall stature, learning problems, and other features in some girls and women. Some females with triple X syndrome have an extra X chromosome in only some of their cells. This phenomenon is called 46,XX/47,XXX mosaicism. | triple X syndrome |
Is triple X syndrome inherited ? | Most cases of triple X syndrome are not inherited. The chromosomal change usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction can result in reproductive cells with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of the X chromosome as a result of nondisjunction. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra X chromosome in each of the body's cells. 46,XX/47,XXX mosaicism is also not inherited. It occurs as a random event during cell division in early embryonic development. As a result, some of an affected person's cells have two X chromosomes (46,XX), and other cells have three X chromosomes (47,XXX). | triple X syndrome |
What are the treatments for triple X syndrome ? | These resources address the diagnosis or management of triple X syndrome: - Association for X and Y Chromosome Variations (AXYS): Trisomy X Syndrome - Genetic Testing Registry: Trisomy X syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | triple X syndrome |
What is (are) cerebral cavernous malformation ? | Cerebral cavernous malformations are collections of small blood vessels (capillaries) in the brain that are enlarged and irregular in structure. These capillaries have abnormally thin walls, and they lack other support tissues, such as elastic fibers, which normally make them stretchy. As a result, the blood vessels are prone to leakage, which can cause the health problems related to this condition. Cavernous malformations can occur anywhere in the body, but usually produce serious signs and symptoms only when they occur in the brain and spinal cord (which are described as cerebral). Approximately 25 percent of individuals with cerebral cavernous malformations never experience any related health problems. Other people with this condition may experience serious signs and symptoms such as headaches, seizures, paralysis, hearing or vision loss, and bleeding in the brain (cerebral hemorrhage). Severe brain hemorrhages can result in death. The location and number of cerebral cavernous malformations determine the severity of this disorder. These malformations can change in size and number over time. There are two forms of the condition: familial and sporadic. The familial form is passed from parent to child, and affected individuals typically have multiple cerebral cavernous malformations. The sporadic form occurs in people with no family history of the disorder. These individuals typically have only one malformation. | cerebral cavernous malformation |
How many people are affected by cerebral cavernous malformation ? | Cerebral cavernous malformations affect about 0.5 percent of the population worldwide. | cerebral cavernous malformation |
What are the genetic changes related to cerebral cavernous malformation ? | Mutations in at least three genes, KRIT1 (also known as CCM1), CCM2, and PDCD10 (also known as CCM3), cause familial cerebral cavernous malformations. The precise functions of these genes are not fully understood. Studies show that the proteins produced from these genes are found in the junctions connecting neighboring blood vessel cells. The proteins interact with each other as part of a complex that strengthens the interactions between cells and limits leakage from the blood vessels. Mutations in any of the three genes impair the function of the protein complex, resulting in weakened cell-to-cell junctions and increased leakage from vessels as seen in cerebral cavernous malformations. Mutations in these three genes account for 85 to 95 percent of all cases of familial cerebral cavernous malformations. The remaining 5 to 15 percent of cases may be due to mutations in unidentified genes or to other unknown causes. Mutations in the KRIT1, CCM2, and PDCD10 genes are not involved in sporadic cerebral cavernous malformations. The cause of this form of the condition is unknown. | cerebral cavernous malformation |
Is cerebral cavernous malformation inherited ? | This condition has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In the familial form, an affected person inherits the mutation from one affected parent. Most people with cerebral cavernous malformations have the sporadic form of the disorder. These cases occur in people with no history of the disorder in their family. | cerebral cavernous malformation |
What are the treatments for cerebral cavernous malformation ? | These resources address the diagnosis or management of cerebral cavernous malformation: - Angioma Alliance: Imaging and Diagnostics - Gene Review: Gene Review: Familial Cerebral Cavernous Malformation - Genetic Testing Registry: Cerebral cavernous malformation - Genetic Testing Registry: Cerebral cavernous malformations 1 - Genetic Testing Registry: Cerebral cavernous malformations 2 - Genetic Testing Registry: Cerebral cavernous malformations 3 - MedlinePlus Encyclopedia: Cerebral angiography These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | cerebral cavernous malformation |
What is (are) complement component 2 deficiency ? | Complement component 2 deficiency is a disorder that causes the immune system to malfunction, resulting in a form of immunodeficiency. Immunodeficiencies are conditions in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria and viruses. People with complement component 2 deficiency have a significantly increased risk of recurrent bacterial infections, specifically of the lungs (pneumonia), the membrane covering the brain and spinal cord (meningitis), and the blood (sepsis), which may be life-threatening. These infections most commonly occur in infancy and childhood and become less frequent in adolescence and adulthood. Complement component 2 deficiency is also associated with an increased risk of developing autoimmune disorders such as systemic lupus erythematosus (SLE) or vasculitis. Autoimmune disorders occur when the immune system malfunctions and attacks the body's tissues and organs. Between 10 and 20 percent of individuals with complement component 2 deficiency develop SLE. Females with complement component 2 deficiency are more likely to have SLE than affected males, but this is also true of SLE in the general population. The severity of complement component 2 deficiency varies widely. While some affected individuals experience recurrent infections and other immune system difficulties, others do not have any health problems related to the disorder. | complement component 2 deficiency |
How many people are affected by complement component 2 deficiency ? | In Western countries, complement component 2 deficiency is estimated to affect 1 in 20,000 individuals; its prevalence in other areas of the world is unknown. | complement component 2 deficiency |
What are the genetic changes related to complement component 2 deficiency ? | Complement component 2 deficiency is caused by mutations in the C2 gene. This gene provides instructions for making the complement component 2 protein, which helps regulate a part of the body's immune response known as the complement system. The complement system is a group of proteins that work together to destroy foreign invaders, trigger inflammation, and remove debris from cells and tissues. The complement component 2 protein is involved in the pathway that turns on (activates) the complement system when foreign invaders, such as bacteria, are detected. The most common C2 gene mutation, which is found in more than 90 percent of people with complement component 2 deficiency, prevents the production of complement component 2 protein. A lack of this protein impairs activation of the complement pathway. As a result, the complement system's ability to fight infections is diminished. It is unclear how complement component 2 deficiency leads to an increase in autoimmune disorders. Researchers speculate that the dysfunctional complement system is unable to distinguish what it should attack, and it sometimes attacks normal tissues, leading to autoimmunity. Alternatively, the dysfunctional complement system may perform partial attacks on invading molecules, which leaves behind foreign fragments that are difficult to distinguish from the body's tissues, so the complement system sometimes attacks the body's own cells. It is likely that other factors, both genetic and environmental, play a role in the variability of the signs and symptoms of complement component 2 deficiency. | complement component 2 deficiency |
Is complement component 2 deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | complement component 2 deficiency |
What are the treatments for complement component 2 deficiency ? | These resources address the diagnosis or management of complement component 2 deficiency: - Genetic Testing Registry: Complement component 2 deficiency - MedlinePlus Encyclopedia: Complement - MedlinePlus Encyclopedia: Immunodeficiency Disorders - Primary Immune Deficiency Treatment Consortium These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | complement component 2 deficiency |
What is (are) aromatic l-amino acid decarboxylase deficiency ? | Aromatic l-amino acid decarboxylase (AADC) deficiency is an inherited disorder that affects the way signals are passed between certain cells in the nervous system. Signs and symptoms of AADC deficiency generally appear in the first year of life. Affected infants may have severe developmental delay, weak muscle tone (hypotonia), muscle stiffness, difficulty moving, and involuntary writhing movements of the limbs (athetosis). They may be lacking in energy (lethargic), feed poorly, startle easily, and have sleep disturbances. People with AADC deficiency may also experience episodes called oculogyric crises that involve abnormal rotation of the eyeballs; extreme irritability and agitation; and pain, muscle spasms, and uncontrolled movements, especially of the head and neck. AADC deficiency may affect the autonomic nervous system, which controls involuntary body processes such as the regulation of blood pressure and body temperature. Resulting signs and symptoms can include droopy eyelids (ptosis), constriction of the pupils of the eyes (miosis), inappropriate or impaired sweating, nasal congestion, drooling, reduced ability to control body temperature, low blood pressure (hypotension), backflow of acidic stomach contents into the esophagus (gastroesophageal reflux), low blood sugar (hypoglycemia), fainting (syncope), and cardiac arrest. Signs and symptoms of AADC deficiency tend to worsen late in the day or when the individual is tired, and improve after sleep. | aromatic l-amino acid decarboxylase deficiency |
How many people are affected by aromatic l-amino acid decarboxylase deficiency ? | AADC deficiency is a rare disorder. Only about 100 people with this condition have been described in the medical literature worldwide; about 20 percent of these individuals are from Taiwan. | aromatic l-amino acid decarboxylase deficiency |
What are the genetic changes related to aromatic l-amino acid decarboxylase deficiency ? | Mutations in the DDC gene cause AADC deficiency. The DDC gene provides instructions for making the AADC enzyme, which is important in the nervous system. This enzyme helps produce dopamine and serotonin from other molecules. Dopamine and serotonin are neurotransmitters, which are chemical messengers that transmit signals between nerve cells, both in the brain and spinal cord (central nervous system) and in other parts of the body (peripheral nervous system). Mutations in the DDC gene result in reduced activity of the AADC enzyme. Without enough of this enzyme, nerve cells produce less dopamine and serotonin. Dopamine and serotonin are necessary for normal nervous system function, and changes in the levels of these neurotransmitters contribute to the developmental delay, intellectual disability, abnormal movements, and autonomic dysfunction seen in people with AADC deficiency. | aromatic l-amino acid decarboxylase deficiency |
Is aromatic l-amino acid decarboxylase deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | aromatic l-amino acid decarboxylase deficiency |
What are the treatments for aromatic l-amino acid decarboxylase deficiency ? | These resources address the diagnosis or management of aromatic l-amino acid decarboxylase deficiency: - Genetic Testing Registry: Deficiency of aromatic-L-amino-acid decarboxylase These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | aromatic l-amino acid decarboxylase deficiency |
What is (are) Stormorken syndrome ? | Stormorken syndrome is a rare condition that affects many body systems. Affected individuals usually have thrombocytopenia, in which there are abnormally low numbers of blood cells called platelets. Platelets are involved in normal blood clotting; a shortage of platelets typically results in easy bruising and abnormal bleeding. In addition, affected individuals often have a muscle disorder, called tubular aggregate myopathy, that leads to muscle weakness. Another feature of Stormorken syndrome is permanent constriction of the pupils of the eyes (miosis), which may be caused by abnormalities in the muscles that control the size of the pupils. Other features include lack of a functioning spleen (asplenia), scaly skin (ichthyosis), headaches, and difficulty with reading and spelling (dyslexia). | Stormorken syndrome |
How many people are affected by Stormorken syndrome ? | Stormorken syndrome is a rare disorder. Approximately a dozen cases have been reported in the medical literature. | Stormorken syndrome |
What are the genetic changes related to Stormorken syndrome ? | Stormorken syndrome is caused by a mutation in the STIM1 gene. The protein produced from this gene is involved in controlling the entry of positively charged calcium atoms (calcium ions) into cells. The STIM1 protein recognizes when calcium ion levels are low and stimulates the flow of ions into the cell through special channels in the cell membrane called calcium-release activated calcium (CRAC) channels. The flow of calcium ions through CRAC channels triggers signaling within cells that helps control gene activity, cell growth and division, and immune function. The STIM1 gene mutation involved in Stormorken syndrome leads to production of a STIM1 protein that is constantly turned on (constitutively active), which means it continually stimulates calcium ion entry through CRAC channels regardless of ion levels. Researchers suggest that the abnormal ion flow in platelets causes the cells to die earlier than usual, leading to thrombocytopenia and bleeding problems in people with Stormorken syndrome. It is unknown how constitutively active STIM1 leads to the other features of the disorder. | Stormorken syndrome |
Is Stormorken syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. | Stormorken syndrome |
What are the treatments for Stormorken syndrome ? | These resources address the diagnosis or management of Stormorken syndrome: - Genetic Testing Registry: Stormorken syndrome These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Stormorken syndrome |
What is (are) Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis ? | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis (NFJS/DPR) represents a rare type of ectodermal dysplasia, a group of about 150 conditions characterized by abnormal development of ectodermal tissues including the skin, hair, nails, teeth, and sweat glands. NFJS and DPR were originally described as separate conditions; however, because they have similar features and are caused by mutations in the same gene, they are now often considered forms of the same disorder. Among the most common signs of NFJS/DPR is a net-like pattern of dark brown or gray skin coloring, known as reticulate hyperpigmentation. This darker pigmentation is seen most often on the neck, chest, and abdomen, although it can also occur in and around the eyes and mouth. Reticulate hyperpigmentation appears in infancy or early childhood. It may fade with age or persist throughout life. NFJS/DPR also affects the skin on the hands and feet. The skin on the palms of the hands and soles of the feet often becomes thick, hard, and callused, a condition known as palmoplantar keratoderma. Some affected individuals also have blistering on their palms and soles. Their fingernails and toenails may be malformed, brittle, and either thicker or thinner than usual. Most affected individuals are missing the patterned ridges on the skin of the hands and feet, called dermatoglyphs, that are the basis for each person's unique fingerprints. Additional features of NFJS/DPR can include a reduced ability to sweat (hypohidrosis) or excess sweating (hyperhidrosis) and dental abnormalities. Some affected individuals also have hair loss (alopecia) on the scalp, eyebrows, and underarms. The alopecia is described as noncicatricial because it does not leave scars (cicatrices). | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis |
How many people are affected by Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis ? | NFJS/DPR is a rare condition; its prevalence is unknown. Only a few affected families have been reported in the medical literature. | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis |
What are the genetic changes related to Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis ? | NFJS/DPR results from mutations in the KRT14 gene. This gene provides instructions for making a protein called keratin 14. Keratins are tough, fibrous proteins that provide strength and resiliency to the outer layer of the skin (the epidermis). Researchers believe that keratin 14 may also play a role in the formation of sweat glands and the development of dermatoglyphs. The KRT14 gene mutations that cause NFJS/DPR most likely reduce the amount of functional keratin 14 that is produced in cells. A shortage of this protein makes cells in the epidermis more likely to self-destruct (undergo apoptosis). The resulting loss of these cells alters the normal development and structure of ectodermal tissues, which likely underlies most of the skin and nail problems characteristic of NFJS/DPR. However, it is unclear how a shortage of keratin 14 is related to changes in skin pigmentation. | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis |
Is Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis |
What are the treatments for Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis ? | These resources address the diagnosis or management of NFJS/DPR: - Foundation for Ichthyosis and Related Skin Types (FIRST): Palmoplantar Keratodermas - Genetic Testing Registry: Dermatopathia pigmentosa reticularis - Genetic Testing Registry: Naegeli-Franceschetti-Jadassohn syndrome - MedlinePlus Encyclopedia: Ectodermal Dysplasia - MedlinePlus Encyclopedia: Nail Abnormalities These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Naegeli-Franceschetti-Jadassohn syndrome/dermatopathia pigmentosa reticularis |
What is (are) trisomy 18 ? | Trisomy 18, also called Edwards syndrome, is a chromosomal condition associated with abnormalities in many parts of the body. Individuals with trisomy 18 often have slow growth before birth (intrauterine growth retardation) and a low birth weight. Affected individuals may have heart defects and abnormalities of other organs that develop before birth. Other features of trisomy 18 include a small, abnormally shaped head; a small jaw and mouth; and clenched fists with overlapping fingers. Due to the presence of several life-threatening medical problems, many individuals with trisomy 18 die before birth or within their first month. Five to 10 percent of children with this condition live past their first year, and these children often have severe intellectual disability. | trisomy 18 |
How many people are affected by trisomy 18 ? | Trisomy 18 occurs in about 1 in 5,000 live-born infants; it is more common in pregnancy, but many affected fetuses do not survive to term. Although women of all ages can have a child with trisomy 18, the chance of having a child with this condition increases as a woman gets older. | trisomy 18 |
What are the genetic changes related to trisomy 18 ? | Most cases of trisomy 18 result from having three copies of chromosome 18 in each cell in the body instead of the usual two copies. The extra genetic material disrupts the normal course of development, causing the characteristic features of trisomy 18. Approximately 5 percent of people with trisomy 18 have an extra copy of chromosome 18 in only some of the body's cells. In these people, the condition is called mosaic trisomy 18. The severity of mosaic trisomy 18 depends on the type and number of cells that have the extra chromosome. The development of individuals with this form of trisomy 18 may range from normal to severely affected. Very rarely, part of the long (q) arm of chromosome 18 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) or very early in embryonic development. Affected individuals have two copies of chromosome 18, plus the extra material from chromosome 18 attached to another chromosome. People with this genetic change are said to have partial trisomy 18. If only part of the q arm is present in three copies, the physical signs of partial trisomy 18 may be less severe than those typically seen in trisomy 18. If the entire q arm is present in three copies, individuals may be as severely affected as if they had three full copies of chromosome 18. | trisomy 18 |
Is trisomy 18 inherited ? | Most cases of trisomy 18 are not inherited, but occur as random events during the formation of eggs and sperm. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 18. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 18 in each of the body's cells. Mosaic trisomy 18 is also not inherited. It occurs as a random event during cell division early in embryonic development. As a result, some of the body's cells have the usual two copies of chromosome 18, and other cells have three copies of this chromosome. Partial trisomy 18 can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 18 and another chromosome. This rearrangement is called a balanced translocation because there is no extra material from chromosome 18. Although they do not have signs of trisomy 18, people who carry this type of balanced translocation are at an increased risk of having children with the condition. | trisomy 18 |
What are the treatments for trisomy 18 ? | These resources address the diagnosis or management of trisomy 18: - Genetic Testing Registry: Complete trisomy 18 syndrome - MedlinePlus Encyclopedia: Trisomy 18 These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | trisomy 18 |
What is (are) sick sinus syndrome ? | Sick sinus syndrome (also known as sinus node dysfunction) is a group of related heart conditions that can affect how the heart beats. "Sick sinus" refers to the sino-atrial (SA) node, which is an area of specialized cells in the heart that functions as a natural pacemaker. The SA node generates electrical impulses that start each heartbeat. These signals travel from the SA node to the rest of the heart, signaling the heart (cardiac) muscle to contract and pump blood. In people with sick sinus syndrome, the SA node does not function normally. In some cases, it does not produce the right signals to trigger a regular heartbeat. In others, abnormalities disrupt the electrical impulses and prevent them from reaching the rest of the heart. Sick sinus syndrome tends to cause the heartbeat to be too slow (bradycardia), although occasionally the heartbeat is too fast (tachycardia). In some cases, the heartbeat rapidly switches from being too fast to being too slow, a condition known as tachycardia-bradycardia syndrome. Symptoms related to abnormal heartbeats can include dizziness, light-headedness, fainting (syncope), a sensation of fluttering or pounding in the chest (palpitations), and confusion or memory problems. During exercise, many affected individuals experience chest pain, difficulty breathing, or excessive tiredness (fatigue). Once symptoms of sick sinus syndrome appear, they usually worsen with time. However, some people with the condition never experience any related health problems. Sick sinus syndrome occurs most commonly in older adults, although it can be diagnosed in people of any age. The condition increases the risk of several life-threatening problems involving the heart and blood vessels. These include a heart rhythm abnormality called atrial fibrillation, heart failure, cardiac arrest, and stroke. | sick sinus syndrome |
How many people are affected by sick sinus syndrome ? | Sick sinus syndrome accounts for 1 in 600 patients with heart disease who are over age 65. The incidence of this condition increases with age. | sick sinus syndrome |
What are the genetic changes related to sick sinus syndrome ? | Sick sinus syndrome can result from genetic or environmental factors. In many cases, the cause of the condition is unknown. Genetic changes are an uncommon cause of sick sinus syndrome. Mutations in two genes, SCN5A and HCN4, have been found to cause the condition in a small number of families. These genes provide instructions for making proteins called ion channels that transport positively charged atoms (ions) into cardiac cells, including cells that make up the SA node. The flow of these ions is essential for creating the electrical impulses that start each heartbeat and coordinate contraction of the cardiac muscle. Mutations in these genes reduce the flow of ions, which alters the SA node's ability to create and spread electrical signals. These changes lead to abnormal heartbeats and the other symptoms of sick sinus syndrome. A particular variation in another gene, MYH6, appears to increase the risk of developing sick sinus syndrome. The protein produced from the MYH6 gene forms part of a larger protein called myosin, which generates the mechanical force needed for cardiac muscle to contract. Researchers believe that the MYH6 gene variation changes the structure of myosin, which can affect cardiac muscle contraction and increase the likelihood of developing an abnormal heartbeat. More commonly, sick sinus syndrome is caused by other factors that alter the structure or function of the SA node. These include a variety of heart conditions, other disorders such as muscular dystrophy, abnormal inflammation, or a shortage of oxygen (hypoxia). Certain medications, such as drugs given to treat abnormal heart rhythms or high blood pressure, can also disrupt SA node function. One of the most common causes of sick sinus syndrome in children is trauma to the SA node, such as damage that occurs during heart surgery. In older adults, sick sinus syndrome is often associated with age-related changes in the heart. Over time, the SA node may harden and develop scar-like damage (fibrosis) that prevents it from working properly. | sick sinus syndrome |
Is sick sinus syndrome inherited ? | Most cases of sick sinus syndrome are not inherited. They are described as sporadic, which means they occur in people with no history of the disorder in their family. When sick sinus syndrome results from mutations in the HCN4 gene, it has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. When sick sinus syndrome is caused by mutations in the SCN5A gene, it is inherited in an autosomal recessive pattern. Autosomal recessive inheritance means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | sick sinus syndrome |
What are the treatments for sick sinus syndrome ? | These resources address the diagnosis or management of sick sinus syndrome: - Cleveland Clinic: Management of Arrhythmias - Genetic Testing Registry: Sick sinus syndrome 1, autosomal recessive - Genetic Testing Registry: Sick sinus syndrome 2, autosomal dominant - Genetic Testing Registry: Sick sinus syndrome 3, susceptibility to - National Heart Lung and Blood Institute: What Is a Pacemaker? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | sick sinus syndrome |
What is (are) infantile systemic hyalinosis ? | Infantile systemic hyalinosis is a disorder that severely affects many areas of the body, including the skin, joints, bones, and internal organs. Hyalinosis refers to the abnormal accumulation of a clear (hyaline) substance in body tissues. The signs and symptoms of this condition are present at birth or develop within the first few months of life. Infantile systemic hyalinosis is characterized by painful skin bumps that frequently appear on the hands, neck, scalp, ears, and nose. They also develop in joint creases and the genital region. These skin bumps may be large or small and often increase in number over time. Lumps of noncancerous tissue also form in the muscles and internal organs of children with infantile systemic hyalinosis, causing pain and severe complications. Most affected individuals develop a condition called protein-losing enteropathy due to the formation of lumps in their intestines. This condition results in severe diarrhea, failure to gain weight and grow at the expected rate (failure to thrive), and general wasting and weight loss (cachexia). Infantile systemic hyalinosis is also characterized by overgrowth of the gums (gingival hypertrophy). Additionally, people with this condition have joint deformities (contractures) that impair movement. Affected individuals may grow slowly and have bone abnormalities. Although children with infantile systemic hyalinosis have severe physical limitations, mental development is typically normal. Affected individuals often do not survive beyond early childhood due to chronic diarrhea and recurrent infections. | infantile systemic hyalinosis |
How many people are affected by infantile systemic hyalinosis ? | The prevalence of infantile systemic hyalinosis is unknown. Fewer than 20 people with this disorder have been reported. | infantile systemic hyalinosis |
What are the genetic changes related to infantile systemic hyalinosis ? | Mutations in the ANTXR2 gene (also known as the CMG2 gene) cause infantile systemic hyalinosis. The ANTXR2 gene provides instructions for making a protein involved in the formation of tiny blood vessels (capillaries). Researchers believe that the ANTXR2 protein is also important for maintaining the structure of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. The signs and symptoms of infantile systemic hyalinosis are caused by the accumulation of a hyaline substance in different parts of the body. The nature of this substance is not well known, but it is likely made up of protein and sugar molecules. Researchers suspect that mutations in the ANTXR2 gene disrupt the formation of basement membranes, allowing the hyaline substance to leak through and build up in various body tissues. | infantile systemic hyalinosis |
Is infantile systemic hyalinosis inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | infantile systemic hyalinosis |
What are the treatments for infantile systemic hyalinosis ? | These resources address the diagnosis or management of infantile systemic hyalinosis: - Gene Review: Gene Review: Hyalinosis, Inherited Systemic - Genetic Testing Registry: Hyaline fibromatosis syndrome - MedlinePlus Encyclopedia: Protein-losing enteropathy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | infantile systemic hyalinosis |
What is (are) autosomal recessive congenital methemoglobinemia ? | Autosomal recessive congenital methemoglobinemia is an inherited condition that mainly affects the function of red blood cells. Specifically, it alters a molecule within these cells called hemoglobin. Hemoglobin carries oxygen to cells and tissues throughout the body. In people with autosomal recessive congenital methemoglobinemia, some of the normal hemoglobin is replaced by an abnormal form called methemoglobin, which is unable to deliver oxygen to the body's tissues. As a result, tissues in the body become oxygen deprived, leading to a bluish appearance of the skin, lips, and nails (cyanosis). There are two forms of autosomal recessive congenital methemoglobinemia: types I and II. People with type I have cyanosis from birth and may experience weakness or shortness of breath related to the shortage of oxygen in their tissues. People with type II have cyanosis as well as severe neurological problems. After a few months of apparently normal development, children with type II develop severe brain dysfunction (encephalopathy), uncontrolled muscle tensing (dystonia), and involuntary limb movements (choreoathetosis); also, the size of their head remains small and does not grow in proportion with their body (microcephaly). People with type II have severe intellectual disability; they can recognize faces and usually babble but speak no words. They can sit unassisted and grip objects but have impaired motor skills that leave them unable to walk. In type II, growth is often slowed. Abnormal facial muscle movements can interfere with swallowing, which can lead to feeding difficulties and further slow growth. People with autosomal recessive congenital methemoglobinemia type I have a normal life expectancy, but people with type II often do not survive past early adulthood. | autosomal recessive congenital methemoglobinemia |
How many people are affected by autosomal recessive congenital methemoglobinemia ? | The incidence of autosomal recessive congenital methemoglobinemia is unknown. | autosomal recessive congenital methemoglobinemia |
What are the genetic changes related to autosomal recessive congenital methemoglobinemia ? | Autosomal recessive congenital methemoglobinemia is caused by mutations in the CYB5R3 gene. This gene provides instruction for making an enzyme called cytochrome b5 reductase 3. This enzyme is involved in transferring negatively charged particles called electrons from one molecule to another. Two versions (isoforms) of this enzyme are produced from the CYB5R3 gene. The soluble isoform is present only in red blood cells, and the membrane-bound isoform is found in all other cell types. Each hemoglobin molecule contains four iron atoms, which are needed to carry oxygen. In normal red blood cells, the iron in hemoglobin is ferrous (Fe2+), but it can spontaneously become ferric (Fe3+). When hemoglobin contains ferric iron, it is methemoglobin. The soluble isoform of cytochrome b5 reductase 3 changes ferric iron back to ferrous iron so hemoglobin can deliver oxygen to tissues. Normally, red blood cells contain less than 2 percent methemoglobin. The membrane-bound isoform is widely used in the body. This isoform is necessary for many chemical reactions, including the breakdown and formation of fatty acids, the formation of cholesterol, and the breakdown of various molecules and drugs. CYB5R3 gene mutations that cause autosomal recessive congenital methemoglobinemia type I typically reduce enzyme activity or stability. As a result, the enzyme cannot efficiently change ferric iron to ferrous iron, leading to a 10 to 50 percent increase in methemoglobin within red blood cells. This increase in methemoglobin and the corresponding decrease in normal hemoglobin reduces the amount of oxygen delivered to tissues. The altered enzyme activity affects only red blood cells because other cells can compensate for a decrease in enzyme activity, but red blood cells cannot. Mutations that cause autosomal recessive congenital methemoglobinemia type II usually result in a complete loss of enzyme activity. Cells cannot compensate for a complete loss of this enzyme, which results in a 10 to 70 percent increase in methemoglobin within red blood cells. This increase in methemoglobin and the corresponding decrease in normal hemoglobin leads to cyanosis. The lack of enzyme activity in other cells leads to the neurological features associated with type II. Researchers suspect that the neurological problems are caused by impaired fatty acid and cholesterol formation, which reduces the production of a fatty substance called myelin. Myelin insulates nerve cells and promotes the rapid transmission of nerve impulses. This reduced ability to form myelin (hypomyelination) leads to a loss of nerve cells, particularly in the brain. The loss of these cells likely contributes to the encephalopathy and movement disorders characteristic of autosomal recessive congenital methemoglobinemia type II. | autosomal recessive congenital methemoglobinemia |
Is autosomal recessive congenital methemoglobinemia inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | autosomal recessive congenital methemoglobinemia |
What are the treatments for autosomal recessive congenital methemoglobinemia ? | These resources address the diagnosis or management of autosomal recessive congenital methemoglobinemia: - Genetic Testing Registry: METHEMOGLOBINEMIA, TYPE I - Genetic Testing Registry: Methemoglobinemia type 2 - KidsHealth from Nemours: Blood Test: Hemoglobin - MedlinePlus Encyclopedia: Hemoglobin - MedlinePlus Encyclopedia: Methemoglobinemia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | autosomal recessive congenital methemoglobinemia |
What is (are) periventricular heterotopia ? | Periventricular heterotopia is a condition in which nerve cells (neurons) do not migrate properly during the early development of the fetal brain, from about the 6th week to the 24th week of pregnancy. Heterotopia means "out of place." In normal brain development, neurons form in the periventricular region, located around fluid-filled cavities (ventricles) near the center of the brain. The neurons then migrate outward to form the exterior of the brain (cerebral cortex) in six onion-like layers. In periventricular heterotopia, some neurons fail to migrate to their proper position and form clumps around the ventricles. Periventricular heterotopia usually becomes evident when seizures first appear, often during the teenage years. The nodules around the ventricles are then typically discovered when magnetic resonance imaging (MRI) studies are done. Affected individuals usually have normal intelligence, although some have mild intellectual disability. Difficulty with reading and spelling (dyslexia) has been reported in some people with periventricular heterotopia. Less commonly, individuals with periventricular heterotopia may have more severe brain malformations, small head size (microcephaly), developmental delays, recurrent infections, blood vessel abnormalities, or other problems. Periventricular heterotopia may also occur in association with other conditions such as Ehlers-Danlos syndrome, which results in extremely flexible joints, skin that stretches easily, and fragile blood vessels. | periventricular heterotopia |
How many people are affected by periventricular heterotopia ? | Periventricular heterotopia is a rare condition. Its incidence is unknown. | periventricular heterotopia |
What are the genetic changes related to periventricular heterotopia ? | Periventricular heterotopia is related to chromosome 5. Mutations in the ARFGEF2 and FLNA genes cause periventricular heterotopia. In most cases, periventricular heterotopia is caused by mutations in the FLNA gene. This gene provides instructions for producing the protein filamin A, which helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Certain mutations in the FLNA gene result in an impaired FLNA protein that cannot perform this function, disrupting the normal migration patterns of neurons during brain development. Periventricular heterotopia can also be caused by mutations in the ARFGEF2 gene. This gene provides instructions for making a protein that is involved in the movement (trafficking) of small sac-like structures (vesicles) within the cell. Vesicle trafficking is important in controlling the migration of neurons during the development of the brain. Mutations in the ARFGEF2 gene may disrupt this function, which could result in the abnormal neuronal migration seen in periventricular heterotopia. Researchers believe that mutations in the FLNA or ARFGEF2 genes may also result in weakening of the attachments (adhesion) between cells that form the lining of the ventricles. A weakened ventricular lining could allow some neurons to form clumps around the ventricles while others migrate normally to the exterior of the brain, as seen in periventricular heterotopia. In a few cases, periventricular heterotopia has been associated with abnormalities in chromosome 5. In each case, the affected individual had extra genetic material caused by an abnormal duplication of part of this chromosome. It is not known how this duplicated genetic material results in the signs and symptoms of periventricular heterotopia. | periventricular heterotopia |
Is periventricular heterotopia inherited ? | Periventricular heterotopia can have different inheritance patterns. When this condition is caused by mutations in the FLNA gene, it is inherited in an X-linked dominant pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. The inheritance is dominant if one copy of the altered gene in each cell is sufficient to cause the condition. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked periventricular heterotopia, males experience much more severe symptoms of the disorder than females, and in most cases die before birth. In about 50 percent of cases of X-linked periventricular heterotopia, an affected person inherits the mutation from a mother who is also affected. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. Periventricular heterotopia caused by mutations in the ARFGEF2 gene is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Individuals with periventricular heterotopia in whom ARFGEF2 gene mutations have been identified have a severe form of the disorder, including microcephaly, severe developmental delay, and seizures beginning in infancy. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition. | periventricular heterotopia |
What are the treatments for periventricular heterotopia ? | These resources address the diagnosis or management of periventricular heterotopia: - Gene Review: Gene Review: FLNA-Related Periventricular Nodular Heterotopia - Genetic Testing Registry: Heterotopia, periventricular, associated with chromosome 5p anomalies - Genetic Testing Registry: Heterotopia, periventricular, autosomal recessive - Genetic Testing Registry: X-linked periventricular heterotopia These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | periventricular heterotopia |
What is (are) Chanarin-Dorfman syndrome ? | Chanarin-Dorfman syndrome is a condition in which fats (lipids) are stored abnormally in the body. Affected individuals cannot break down certain fats called triglycerides, and these fats accumulate in organs and tissues, including skin, liver, muscles, intestine, eyes, and ears. People with this condition also have dry, scaly skin (ichthyosis), which is usually present at birth. Additional features of this condition include an enlarged liver (hepatomegaly), clouding of the lens of the eyes (cataracts), difficulty with coordinating movements (ataxia), hearing loss, short stature, muscle weakness (myopathy), involuntary movement of the eyes (nystagmus), and mild intellectual disability. The signs and symptoms vary greatly among individuals with Chanarin-Dorfman syndrome. Some people may have ichthyosis only, while others may have problems affecting many areas of the body. | Chanarin-Dorfman syndrome |
How many people are affected by Chanarin-Dorfman syndrome ? | Chanarin-Dorfman syndrome is a rare condition; its incidence is unknown. | Chanarin-Dorfman syndrome |
What are the genetic changes related to Chanarin-Dorfman syndrome ? | Mutations in the ABHD5 gene cause Chanarin-Dorfman syndrome. The ABHD5 gene provides instructions for making a protein that turns on (activates) the ATGL enzyme, which breaks down triglycerides. Triglycerides are the main source of stored energy in cells. These fats must be broken down into simpler molecules called fatty acids before they can be used for energy. ABHD5 gene mutations impair the protein's ability to activate the ATGL enzyme. An inactive enzyme makes the breakdown of triglycerides impossible, causing them to accumulate in tissues throughout the body. The buildup of triglycerides results in the signs and symptoms of Chanarin-Dorfman syndrome. | Chanarin-Dorfman syndrome |
Is Chanarin-Dorfman syndrome inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | Chanarin-Dorfman syndrome |
What are the treatments for Chanarin-Dorfman syndrome ? | These resources address the diagnosis or management of Chanarin-Dorfman syndrome: - Genetic Testing Registry: Triglyceride storage disease with ichthyosis - MedlinePlus Encyclopedia: Ichthyosis vulgaris These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Chanarin-Dorfman syndrome |
What is (are) Larsen syndrome ? | Larsen syndrome is a disorder that affects the development of bones throughout the body. The signs and symptoms of Larsen syndrome vary widely even within the same family. Affected individuals are usually born with inward- and upward-turning feet (clubfeet) and dislocations of the hips, knees, and elbows. They generally have small extra bones in their wrists and ankles that are visible on x-ray images. The tips of their fingers, especially the thumbs, are typically blunt and square-shaped (spatulate). People with Larsen syndrome may also have an unusually large range of joint movement (hypermobility) and short stature. They can also have abnormal curvature of the spine (kyphosis or scoliosis) that may compress the spinal cord and lead to weakness of the limbs. Characteristic facial features include a prominent forehead (frontal bossing), flattening of the bridge of the nose and of the middle of the face (midface hypoplasia), and wide-set eyes (ocular hypertelorism). Some people with Larsen syndrome have an opening in the roof of the mouth (a cleft palate) or hearing loss caused by malformations in the tiny bones in the ears (ossicles). Some affected individuals experience respiratory problems as a result of weakness of the airways that can lead to partial closing, short pauses in breathing (apnea), and frequent respiratory infections. People with Larsen syndrome can survive into adulthood and intelligence is unaffected. | Larsen syndrome |
How many people are affected by Larsen syndrome ? | Larsen syndrome occurs in approximately 1 in 100,000 newborns. | Larsen syndrome |
What are the genetic changes related to Larsen syndrome ? | Mutations in the FLNB gene cause Larsen syndrome. The FLNB gene provides instructions for making a protein called filamin B. This protein helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin B attaches (binds) to another protein called actin and helps the actin to form the branching network of filaments that makes up the cytoskeleton. It also links actin to many other proteins to perform various functions within the cell, including the cell signaling that helps determine how the cytoskeleton will change as tissues grow and take shape during development. Filamin B is especially important in the development of the skeleton before birth. It is active (expressed) in the cell membranes of cartilage-forming cells (chondrocytes). Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone (a process called ossification), except for the cartilage that continues to cover and protect the ends of bones and is present in the nose, airways (trachea and bronchi), and external ears. Filamin B appears to be important for normal cell growth and division (proliferation) and maturation (differentiation) of chondrocytes and for the ossification of cartilage. FLNB gene mutations that cause Larsen syndrome change single protein building blocks (amino acids) in the filamin B protein or delete a small section of the protein sequence, resulting in an abnormal protein. This abnormal protein appears to have a new, atypical function that interferes with the proliferation or differentiation of chondrocytes, impairing ossification and leading to the signs and symptoms of Larsen syndrome. | Larsen syndrome |
Is Larsen syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family. Autosomal recessive inheritance of Larsen syndrome has been reported in a small number of families. Autosomal recessive means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. In some of these cases, the appearance of autosomal recessive inheritance may actually result from multiple siblings in a family each inheriting a single altered gene from an unaffected parent who has an FLNB mutation only in some or all of their sperm or egg cells. When a mutation is present only in reproductive cells, it is known as germline mosaicism. A few rarer conditions with overlapping signs and symptoms and autosomal recessive inheritance have sometimes been diagnosed as Larsen syndrome, but they are now generally considered to be different disorders because they are typically more severe and are not caused by FLNB gene mutations. | Larsen syndrome |
What are the treatments for Larsen syndrome ? | These resources address the diagnosis or management of Larsen syndrome: - Gene Review: Gene Review: FLNB-Related Disorders - Genetic Testing Registry: Larsen syndrome - Genetic Testing Registry: Larsen syndrome, dominant type These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Larsen syndrome |
What is (are) carnitine palmitoyltransferase II deficiency ? | Carnitine palmitoyltransferase II (CPT II) deficiency is a condition that prevents the body from using certain fats for energy, particularly during periods without food (fasting). There are three main types of CPT II deficiency: a lethal neonatal form, a severe infantile hepatocardiomuscular form, and a myopathic form. The lethal neonatal form of CPT II deficiency becomes apparent soon after birth. Infants with this form of the disorder develop respiratory failure, seizures, liver failure, a weakened heart muscle (cardiomyopathy), and an irregular heart beat (arrhythmia). Affected individuals also have low blood sugar (hypoglycemia) and a low level of ketones, which are produced during the breakdown of fats and used for energy. Together these signs are called hypoketotic hypoglycemia. In many cases, the brain and kidneys are also structurally abnormal. Infants with the lethal neonatal form of CPT II deficiency usually live for a few days to a few months. The severe infantile hepatocardiomuscular form of CPT II deficiency affects the liver, heart, and muscles. Signs and symptoms usually appear within the first year of life. This form involves recurring episodes of hypoketotic hypoglycemia, seizures, an enlarged liver (hepatomegaly), cardiomyopathy, and arrhythmia. Problems related to this form of CPT II deficiency can be triggered by periods of fasting or by illnesses such as viral infections. Individuals with the severe infantile hepatocardiomuscular form of CPT II deficiency are at risk for liver failure, nervous system damage, coma, and sudden death. The myopathic form is the least severe type of CPT II deficiency. This form is characterized by recurrent episodes of muscle pain (myalgia) and weakness and is associated with the breakdown of muscle tissue (rhabdomyolysis). The destruction of muscle tissue releases a protein called myoglobin, which is processed by the kidneys and released in the urine (myoglobinuria). Myoglobin causes the urine to be red or brown. This protein can also damage the kidneys, in some cases leading to life-threatening kidney failure. Episodes of myalgia and rhabdomyolysis may be triggered by exercise, stress, exposure to extreme temperatures, infections, or fasting. The first episode usually occurs during childhood or adolescence. Most people with the myopathic form of CPT II deficiency have no signs or symptoms of the disorder between episodes. | carnitine palmitoyltransferase II deficiency |
How many people are affected by carnitine palmitoyltransferase II deficiency ? | CPT II deficiency is a rare disorder. The lethal neonatal form has been described in at least 18 families, while the severe infantile hepatocardiomuscular form has been identified in approximately 30 families. The myopathic form occurs most frequently, with more than 300 reported cases. | carnitine palmitoyltransferase II deficiency |
What are the genetic changes related to carnitine palmitoyltransferase II deficiency ? | Mutations in the CPT2 gene cause CPT II deficiency. This gene provides instructions for making an enzyme called carnitine palmitoyltransferase 2. This enzyme is essential for fatty acid oxidation, which is the multistep process that breaks down (metabolizes) fats and converts them into energy. Fatty acid oxidation takes place within mitochondria, which are the energy-producing centers in cells. A group of fats called long-chain fatty acids must be attached to a substance known as carnitine to enter mitochondria. Once these fatty acids are inside mitochondria, carnitine palmitoyltransferase 2 removes the carnitine and prepares them for fatty acid oxidation. Fatty acids are a major source of energy for the heart and muscles. During periods of fasting, fatty acids are also an important energy source for the liver and other tissues. Mutations in the CPT2 gene reduce the activity of carnitine palmitoyltransferase 2. Without enough of this enzyme, carnitine is not removed from long-chain fatty acids. As a result, these fatty acids cannot be metabolized to produce energy. Reduced energy production can lead to some of the features of CPT II deficiency, such as hypoketotic hypoglycemia, myalgia, and weakness. Fatty acids and long-chain acylcarnitines (fatty acids still attached to carnitine) may also build up in cells and damage the liver, heart, and muscles. This abnormal buildup causes the other signs and symptoms of the disorder. | carnitine palmitoyltransferase II deficiency |
Is carnitine palmitoyltransferase II deficiency inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | carnitine palmitoyltransferase II deficiency |
What are the treatments for carnitine palmitoyltransferase II deficiency ? | These resources address the diagnosis or management of CPT II deficiency: - Baby's First Test - FOD (Fatty Oxidation Disorders) Family Support Group: Diagnostic Approach to Disorders of Fat Oxidation - Information for Clinicians - Gene Review: Gene Review: Carnitine Palmitoyltransferase II Deficiency - Genetic Testing Registry: CARNITINE PALMITOYLTRANSFERASE II DEFICIENCY, LATE-ONSET - Genetic Testing Registry: CARNITINE PALMITOYLTRANSFERASE II DEFICIENCY, LETHAL NEONATAL - Genetic Testing Registry: Carnitine palmitoyltransferase II deficiency - Genetic Testing Registry: Carnitine palmitoyltransferase II deficiency, infantile These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | carnitine palmitoyltransferase II deficiency |
What is (are) Bietti crystalline dystrophy ? | Bietti crystalline dystrophy is a disorder in which numerous small, yellow or white crystal-like deposits of fatty (lipid) compounds accumulate in the light-sensitive tissue that lines the back of the eye (the retina). The deposits damage the retina, resulting in progressive vision loss. People with Bietti crystalline dystrophy typically begin noticing vision problems in their teens or twenties. They experience a loss of sharp vision (reduction in visual acuity) and difficulty seeing in dim light (night blindness). They usually lose areas of vision (visual field loss), most often side (peripheral) vision. Color vision may also be impaired. The vision problems may worsen at different rates in each eye, and the severity and progression of symptoms varies widely among affected individuals, even within the same family. However, most people with this condition become legally blind by their forties or fifties. Most affected individuals retain some degree of vision, usually in the center of the visual field, although it is typically blurry and cannot be corrected by glasses or contact lenses. Vision impairment that cannot be improved with corrective lenses is called low vision. | Bietti crystalline dystrophy |
How many people are affected by Bietti crystalline dystrophy ? | Bietti crystalline dystrophy has been estimated to occur in 1 in 67,000 people. It is more common in people of East Asian descent, especially those of Chinese and Japanese background. Researchers suggest that Bietti crystalline dystrophy may be underdiagnosed because its symptoms are similar to those of other eye disorders that progressively damage the retina. | Bietti crystalline dystrophy |
What are the genetic changes related to Bietti crystalline dystrophy ? | Bietti crystalline dystrophy is caused by mutations in the CYP4V2 gene. This gene provides instructions for making a member of the cytochrome P450 family of enzymes. These enzymes are involved in the formation and breakdown of various molecules and chemicals within cells. The CYP4V2 enzyme is involved in a multi-step process called fatty acid oxidation in which lipids are broken down and converted into energy, but the enzyme's specific function is not well understood. CYP4V2 gene mutations that cause Bietti crystalline dystrophy impair or eliminate the function of this enzyme and are believed to affect lipid breakdown. However, it is unknown how they lead to the specific signs and symptoms of Bietti crystalline dystrophy. For unknown reasons, the severity of the signs and symptoms differs significantly among individuals with the same CYP4V2 gene mutation. | Bietti crystalline dystrophy |
Is Bietti crystalline dystrophy inherited ? | This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | Bietti crystalline dystrophy |
What are the treatments for Bietti crystalline dystrophy ? | These resources address the diagnosis or management of Bietti crystalline dystrophy: - Gene Review: Gene Review: Bietti Crystalline Dystrophy - Genetic Testing Registry: Bietti crystalline corneoretinal dystrophy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Bietti crystalline dystrophy |
What is (are) cold-induced sweating syndrome ? | Cold-induced sweating syndrome is characterized by problems with regulating body temperature and other abnormalities affecting many parts of the body. In infancy, the features of this condition are often known as Crisponi syndrome. Researchers originally thought that cold-induced sweating syndrome and Crisponi syndrome were separate disorders, but it is now widely believed that they represent the same condition at different times during life. Infants with Crisponi syndrome have unusual facial features, including a flat nasal bridge, upturned nostrils, a long space between the nose and upper lip (philtrum), a high arched roof of the mouth (palate), a small chin (micrognathia), and low-set ears. The muscles in the lower part of the face are weak, leading to severe feeding difficulties, excessive drooling, and breathing problems. Other physical abnormalities associated with Crisponi syndrome include a scaly skin rash, an inability to fully extend the elbows, overlapping fingers and tightly fisted hands, and malformations of the feet and toes. Affected infants startle easily and often tense their facial muscles into a grimace-like expression. By six months of age, infants with Crisponi syndrome develop unexplained high fevers that increase the risk of seizures and sudden death. Many of the health problems associated with Crisponi syndrome improve with time, and affected individuals who survive the newborn period go on to develop other features of cold-induced sweating syndrome in early childhood. Within the first decade of life, affected individuals begin having episodes of profuse sweating (hyperhidrosis) and shivering involving the face, torso, and arms. The excessive sweating is usually triggered by exposure to temperatures below about 65 or 70 degrees Fahrenheit, but it can also be triggered by nervousness or eating sugary foods. Paradoxically, affected individuals tend not to sweat in warmer conditions, instead becoming flushed and overheated in hot environments. Adolescents with cold-induced sweating syndrome typically develop abnormal side-to-side and front-to-back curvature of the spine (scoliosis and kyphosis, often called kyphoscoliosis when they occur together). Although infants may develop life-threatening fevers, affected individuals who survive infancy have a normal life expectancy. | cold-induced sweating syndrome |
How many people are affected by cold-induced sweating syndrome ? | Cold-induced sweating syndrome is a rare condition; its prevalence is unknown. The condition was first identified in the Sardinian population, but it has since been reported in regions worldwide. | cold-induced sweating syndrome |
What are the genetic changes related to cold-induced sweating syndrome ? | About 90 percent of cases of cold-induced sweating syndrome and Crisponi syndrome result from mutations in the CRLF1 gene. These cases are designated as CISS1. The remaining 10 percent of cases are caused by mutations in the CLCF1 gene and are designated as CISS2. The proteins produced from the CRLF1 and CLCF1 genes work together as part of a signaling pathway that is involved in the normal development of the nervous system. This pathway appears to be particularly important for the development and maintenance of motor neurons, which are nerve cells that control muscle movement. Studies suggest that this pathway also has a role in a part of the nervous system known as the sympathetic nervous system, specifically in the regulation of sweating in response to temperature changes and other factors. The proteins produced from the CRLF1 and CLCF1 genes appear to be critical for the normal development and maturation of nerve cells that control the activity of sweat glands. Additionally, the CRLF1 and CLCF1 genes likely have functions outside the nervous system, including roles in the body's inflammatory response and in bone development. However, little is known about their involvement in these processes. Mutations in either the CRLF1 or CLCF1 gene disrupt the normal development of several body systems, including the nervous system. The role of these genes in sympathetic nervous system development may help explain the abnormal sweating that is characteristic of this condition, including unusual sweating patterns and related problems with body temperature regulation. The involvement of these genes in motor neuron development and bone development provides clues to some of the other signs and symptoms of cold-induced sweating syndrome, including distinctive facial features, facial muscle weakness, and skeletal abnormalities. However, little is known about how CRLF1 or CLCF1 gene mutations underlie these other features of cold-induced sweating syndrome. | cold-induced sweating syndrome |
Is cold-induced sweating syndrome inherited ? | Cold-induced sweating syndrome is inherited in anautosomal recessive pattern, which means both copies of the CRLF1 or CLCF1 gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. | cold-induced sweating syndrome |
What are the treatments for cold-induced sweating syndrome ? | These resources address the diagnosis or management of cold-induced sweating syndrome: - Gene Review: Gene Review: Cold-Induced Sweating Syndrome including Crisponi Syndrome - Genetic Testing Registry: Cold-induced sweating syndrome 1 - Genetic Testing Registry: Cold-induced sweating syndrome 2 - Merck Manual Consumer Version: Excessive Sweating These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | cold-induced sweating syndrome |
What is (are) spinal and bulbar muscular atrophy ? | Spinal and bulbar muscular atrophy, also known as Kennedy disease, is a disorder of specialized nerve cells that control muscle movement (motor neurons). These nerve cells originate in the spinal cord and the part of the brain that is connected to the spinal cord (the brainstem). Spinal and bulbar muscular atrophy mainly affects males and is characterized by muscle weakness and wasting (atrophy) that usually begins in adulthood and worsens slowly over time. Muscle wasting in the arms and legs results in cramping; leg muscle weakness can also lead to difficulty walking and a tendency to fall. Certain muscles in the face and throat (bulbar muscles) are also affected, which causes progressive problems with swallowing and speech. Additionally, muscle twitches (fasciculations) are common. Some males with the disorder experience unusual breast development (gynecomastia) and may be unable to father a child (infertile). | spinal and bulbar muscular atrophy |
How many people are affected by spinal and bulbar muscular atrophy ? | This condition affects fewer than 1 in 150,000 males and is very rare in females. | spinal and bulbar muscular atrophy |
What are the genetic changes related to spinal and bulbar muscular atrophy ? | Spinal and bulbar muscular atrophy results from a particular type of mutation in the AR gene. This gene provides instructions for making a protein called an androgen receptor. This receptor attaches (binds) to a class of hormones called androgens, which are involved in male sexual development. Androgens and androgen receptors also have other important functions in both males and females, such as regulating hair growth and sex drive. The AR gene mutation that causes spinal and bulbar muscular atrophy is the abnormal expansion of a DNA segment called a CAG triplet repeat. Normally, this DNA segment is repeated up to about 36 times. In people with spinal and bulbar muscular atrophy, the CAG segment is repeated at least 38 times, and it may be two or three times its usual length. Although the extended CAG region changes the structure of the androgen receptor, it is unclear how the altered protein disrupts nerve cells in the brain and spinal cord. Researchers believe that a fragment of the androgen receptor protein containing the CAG segment accumulates within these cells and interferes with normal cell functions. The nerve cells gradually die, leading to the muscle weakness and wasting seen in this condition. People with a higher number of CAG repeats tend to develop signs and symptoms of spinal and bulbar muscular atrophy at an earlier age. | spinal and bulbar muscular atrophy |
Is spinal and bulbar muscular atrophy inherited ? | This condition is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes the disorder. In most cases, males experience more severe symptoms of the disorder than females (who have two X chromosomes). Females with a mutation in one copy of the AR gene in each cell are typically unaffected. A few females with mutations in both copies of the gene have had mild features related to the condition, including muscle cramps and occasional tremors. Researchers believe that the milder signs and symptoms in females may be related to lower androgen levels. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. | spinal and bulbar muscular atrophy |
What are the treatments for spinal and bulbar muscular atrophy ? | These resources address the diagnosis or management of spinal and bulbar muscular atrophy: - Gene Review: Gene Review: Spinal and Bulbar Muscular Atrophy - Genetic Testing Registry: Bulbo-spinal atrophy X-linked - MedlinePlus Encyclopedia: Muscle Atrophy These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | spinal and bulbar muscular atrophy |
What is (are) Cowden syndrome ? | Cowden syndrome is a disorder characterized by multiple noncancerous, tumor-like growths called hamartomas and an increased risk of developing certain cancers. Almost everyone with Cowden syndrome develops hamartomas. These growths are most commonly found on the skin and mucous membranes (such as the lining of the mouth and nose), but they can also occur in the intestine and other parts of the body. The growth of hamartomas on the skin and mucous membranes typically becomes apparent by a person's late twenties. Cowden syndrome is associated with an increased risk of developing several types of cancer, particularly cancers of the breast, a gland in the lower neck called the thyroid, and the lining of the uterus (the endometrium). Other cancers that have been identified in people with Cowden syndrome include colorectal cancer, kidney cancer, and a form of skin cancer called melanoma. Compared with the general population, people with Cowden syndrome develop these cancers at younger ages, often beginning in their thirties or forties. Other diseases of the breast, thyroid, and endometrium are also common in Cowden syndrome. Additional signs and symptoms can include an enlarged head (macrocephaly) and a rare, noncancerous brain tumor called Lhermitte-Duclos disease. A small percentage of affected individuals have delayed development or intellectual disability. The features of Cowden syndrome overlap with those of another disorder called Bannayan-Riley-Ruvalcaba syndrome. People with Bannayan-Riley-Ruvalcaba syndrome also develop hamartomas and other noncancerous tumors. Both conditions can be caused by mutations in the PTEN gene. Some people with Cowden syndrome have had relatives diagnosed with Bannayan-Riley-Ruvalcaba syndrome, and other individuals have had the characteristic features of both conditions. Based on these similarities, researchers have proposed that Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome represent a spectrum of overlapping features known as PTEN hamartoma tumor syndrome instead of two distinct conditions. Some people have some of the characteristic features of Cowden syndrome, particularly the cancers associated with this condition, but do not meet the strict criteria for a diagnosis of Cowden syndrome. These individuals are often described as having Cowden-like syndrome. | Cowden syndrome |
How many people are affected by Cowden syndrome ? | Although the exact prevalence of Cowden syndrome is unknown, researchers estimate that it affects about 1 in 200,000 people. | Cowden syndrome |
What are the genetic changes related to Cowden syndrome ? | Changes involving at least four genes, PTEN, SDHB, SDHD, and KLLN, have been identified in people with Cowden syndrome or Cowden-like syndrome. Most cases of Cowden syndrome and a small percentage of cases of Cowden-like syndrome result from mutations in the PTEN gene. The protein produced from the PTEN gene is a tumor suppressor, which means that it normally prevents cells from growing and dividing (proliferating) too rapidly or in an uncontrolled way. Mutations in the PTEN gene prevent the protein from regulating cell proliferation effectively, leading to uncontrolled cell division and the formation of hamartomas and cancerous tumors. The PTEN gene likely has other important functions within cells; however, it is unclear how mutations in this gene cause the other features of Cowden syndrome, such as macrocephaly and intellectual disability. Other cases of Cowden syndrome and Cowden-like syndrome result from changes involving the KLLN gene. This gene provides instructions for making a protein called killin. Like the protein produced from the PTEN gene, killin probably acts as a tumor suppressor. The genetic change that causes Cowden syndrome and Cowden-like syndrome is known as promoter hypermethylation. The promoter is a region of DNA near the gene that controls gene activity (expression). Hypermethylation occurs when too many small molecules called methyl groups are attached to the promoter region. The extra methyl groups reduce the expression of the KLLN gene, which means that less killin is produced. A reduced amount of killin may allow abnormal cells to survive and proliferate inappropriately, which can lead to the formation of tumors. A small percentage of people with Cowden syndrome or Cowden-like syndrome have variations in the SDHB or SDHD gene. These genes provide instructions for making parts of an enzyme called succinate dehydrogenase (SDH), which is important for energy production in the cell. This enzyme also plays a role in signaling pathways that regulate cell survival and proliferation. Variations in the SDHB or SDHD gene alter the function of the SDH enzyme. Studies suggest that the defective enzyme may allow cells to grow and divide unchecked, leading to the formation of hamartomas and cancerous tumors. However, researchers are uncertain whether the identified SDHB and SDHD gene variants are directly associated with Cowden syndrome and Cowden-like syndrome. Some of the variants described above have also been identified in people without the features of these conditions. When Cowden syndrome and Cowden-like syndrome are not related to changes in the PTEN, SDHB, SDHD, or KLLN genes, the cause of the conditions is unknown. | Cowden syndrome |
Is Cowden syndrome inherited ? | Cowden syndrome and Cowden-like syndrome are inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the condition and increase the risk of developing cancer. In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. | Cowden syndrome |
What are the treatments for Cowden syndrome ? | These resources address the diagnosis or management of Cowden syndrome: - Gene Review: Gene Review: PTEN Hamartoma Tumor Syndrome (PHTS) - Genetic Testing Registry: Cowden syndrome - Genetic Testing Registry: Cowden syndrome 1 - Genetic Testing Registry: Cowden syndrome 2 - National Cancer Institute: Genetic Testing for Hereditary Cancer Syndromes - University of Iowa: Are Tests for Cowden Syndrome Available? - University of Iowa: How is Cowden Syndrome Diagnosed? - University of Iowa: What Should I Be Doing About This Condition? These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care | Cowden syndrome |
Subsets and Splits
No saved queries yet
Save your SQL queries to embed, download, and access them later. Queries will appear here once saved.