problem
stringlengths
16
191
explanation
stringlengths
6
29k
type
stringlengths
3
136
What is (are) X-linked lissencephaly with abnormal genitalia ?
X-linked lissencephaly with abnormal genitalia (XLAG) is a condition that affects the development of the brain and genitalia. It occurs most often in males. XLAG is characterized by abnormal brain development that results in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. Individuals without any folds in the brain (agyria) typically have more severe symptoms than people with reduced folds and grooves (pachygyria). Individuals with XLAG may also have a lack of development (agenesis) of the tissue connecting the left and right halves of the brain (corpus callosum). The brain abnormalities can cause severe intellectual disability and developmental delay, abnormal muscle stiffness (spasticity), weak muscle tone (hypotonia), and feeding difficulties. Starting soon after birth, babies with XLAG have frequent and recurrent seizures (epilepsy). Most children with XLAG do not survive past early childhood. Another key feature of XLAG in males is abnormal genitalia that can include an unusually small penis (micropenis), undescended testes (cryptorchidism), or external genitalia that do not look clearly male or clearly female (ambiguous genitalia). Additional signs and symptoms of XLAG include chronic diarrhea, periods of increased blood sugar (transient hyperglycemia), and problems with body temperature regulation.
X-linked lissencephaly with abnormal genitalia
How many people are affected by X-linked lissencephaly with abnormal genitalia ?
The incidence of XLAG is unknown; approximately 30 affected families have been described in the medical literature.
X-linked lissencephaly with abnormal genitalia
What are the genetic changes related to X-linked lissencephaly with abnormal genitalia ?
Mutations in the ARX gene cause XLAG. The ARX gene provides instructions for producing a protein that is involved in the development of several organs, including the brain, testes, and pancreas. In the developing brain, the ARX protein is involved with movement and communication in nerve cells (neurons). The ARX protein regulates genes that play a role in the migration of specialized neurons (interneurons) to their proper location. Interneurons relay signals between neurons. In the pancreas and testes, the ARX protein helps to regulate the process by which cells mature to carry out specific functions (differentiation). ARX gene mutations lead to the production of a nonfunctional ARX protein or to the complete absence of ARX protein. As a result, the ARX protein cannot perform its role regulating the activity of genes important for interneuron migration. In addition to impairing normal brain development, a lack of functional ARX protein disrupts cell differentiation during the formation of the testes, leading to abnormal genitalia. It is thought that the disruption of ARX protein function in the pancreas plays a role in the chronic diarrhea and hyperglycemia experienced by individuals with XLAG.
X-linked lissencephaly with abnormal genitalia
Is X-linked lissencephaly with abnormal genitalia 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 each cell. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females, who have two copies of the X chromosome, one altered copy of the gene in each cell can lead to less severe brain malformations or may cause no symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
X-linked lissencephaly with abnormal genitalia
What are the treatments for X-linked lissencephaly with abnormal genitalia ?
These resources address the diagnosis or management of X-linked lissencephaly with abnormal genitalia: - Genetic Testing Registry: Lissencephaly 2, X-linked 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
X-linked lissencephaly with abnormal genitalia
What is (are) neonatal onset multisystem inflammatory disease ?
Neonatal onset multisystem inflammatory disease (NOMID) is a disorder that causes persistent inflammation and tissue damage primarily affecting the nervous system, skin, and joints. Recurrent episodes of mild fever may also occur in this disorder. People with NOMID have a skin rash that is usually present from birth. The rash persists throughout life, although it changes in size and location. Affected individuals often have headaches, seizures, and vomiting resulting from chronic meningitis, which is inflammation of the tissue that covers and protects the brain and spinal cord (meninges). Intellectual disability may occur in some people with this disorder. Hearing and vision problems may result from nerve damage and inflammation in various tissues of the eyes. People with NOMID experience joint inflammation, swelling, and cartilage overgrowth, causing characteristic prominent knees and other skeletal abnormalities that worsen over time. Joint deformities called contractures may restrict the movement of certain joints. Other features of this disorder include short stature with shortening of the lower legs and forearms, and characteristic facial features such as a prominent forehead and protruding eyes. Abnormal deposits of a protein called amyloid (amyloidosis) may cause progressive kidney damage.
neonatal onset multisystem inflammatory disease
How many people are affected by neonatal onset multisystem inflammatory disease ?
NOMID is a very rare disorder; approximately 100 affected individuals have been reported worldwide.
neonatal onset multisystem inflammatory disease
What are the genetic changes related to neonatal onset multisystem inflammatory disease ?
Mutations in the NLRP3 gene (also known as CIAS1) cause NOMID. The NLRP3 gene provides instructions for making a protein called cryopyrin. Cryopyrin belongs to a family of proteins called nucleotide-binding domain and leucine-rich repeat containing (NLR) proteins. These proteins are involved in the immune system, helping to regulate the process of inflammation. Inflammation occurs when the immune system sends signaling molecules and white blood cells to a site of injury or disease to fight microbial invaders and facilitate tissue repair. When this has been accomplished, the body stops (inhibits) the inflammatory response to prevent damage to its own cells and tissues. Cryopyrin is involved in the assembly of a molecular complex called an inflammasome, which helps trigger the inflammatory process. Researchers believe that NLRP3 mutations that cause NOMID result in a hyperactive cryopyrin protein and an inappropriate inflammatory response. Impairment of the body's mechanisms for controlling inflammation results in the episodes of fever and widespread inflammatory damage to the body's cells and tissues seen in NOMID. In about 50 percent of individuals diagnosed with NOMID, no mutations in the NLRP3 gene have been identified. The cause of NOMID in these individuals is unknown.
neonatal onset multisystem inflammatory disease
Is neonatal onset multisystem inflammatory disease 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 almost all cases, NOMID results from new mutations. These cases occur in people with no history of the disorder in their family. A few cases have been reported in which an affected person has inherited the mutation from one affected parent.
neonatal onset multisystem inflammatory disease
What are the treatments for neonatal onset multisystem inflammatory disease ?
These resources address the diagnosis or management of NOMID: - Genetic Testing Registry: Chronic infantile neurological, cutaneous and articular 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
neonatal onset multisystem inflammatory disease
What is (are) aceruloplasminemia ?
Aceruloplasminemia is a disorder in which iron gradually accumulates in the brain and other organs. Iron accumulation in the brain results in neurological problems that generally appear in adulthood and worsen over time. People with aceruloplasminemia develop a variety of movement problems. They may experience involuntary muscle contractions (dystonia) of the head and neck, resulting in repetitive movements and contortions. Other involuntary movements may also occur, such as rhythmic shaking (tremors), jerking movements (chorea), eyelid twitching (blepharospasm), and grimacing. Affected individuals may also have difficulty with coordination (ataxia). Some develop psychiatric problems and a decline of intellectual function (dementia) in their forties or fifties. In addition to neurological problems, affected individuals may have diabetes mellitus caused by iron damage to cells in the pancreas that make insulin, a hormone that helps control blood sugar levels. Iron accumulation in the pancreas reduces the cells' ability to make insulin, which impairs blood sugar regulation and leads to the signs and symptoms of diabetes. Iron accumulation in the tissues and organs results in a corresponding shortage (deficiency) of iron in the blood, leading to a shortage of red blood cells (anemia). Anemia and diabetes usually occur by the time an affected person is in his or her twenties. Affected individuals also have changes in the light-sensitive tissue at the back of the eye (retina) caused by excess iron. The changes result in small opaque spots and areas of tissue degeneration (atrophy) around the edges of the retina. These abnormalities usually do not affect vision but can be observed during an eye examination. The specific features of aceruloplasminemia and their severity may vary, even within the same family.
aceruloplasminemia
How many people are affected by aceruloplasminemia ?
Aceruloplasminemia has been seen worldwide, but its overall prevalence is unknown. Studies in Japan have estimated that approximately 1 in 2 million adults in this population are affected.
aceruloplasminemia
What are the genetic changes related to aceruloplasminemia ?
Mutations in the CP gene cause aceruloplasminemia. The CP gene provides instructions for making a protein called ceruloplasmin, which is involved in iron transport and processing. Ceruloplasmin helps move iron from the organs and tissues of the body and prepares it for incorporation into a molecule called transferrin, which transports it to red blood cells to help carry oxygen. CP gene mutations result in the production of ceruloplasmin protein that is unstable or nonfunctional, or they prevent the protein from being released (secreted) by the cells in which it is made. When ceruloplasmin is unavailable, transport of iron out of the body's tissues is impaired. The resulting iron accumulation damages cells in those tissues, leading to neurological dysfunction, and the other health problems seen in aceruloplasminemia.
aceruloplasminemia
Is aceruloplasminemia 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.
aceruloplasminemia
What are the treatments for aceruloplasminemia ?
These resources address the diagnosis or management of aceruloplasminemia: - Gene Review: Gene Review: Aceruloplasminemia - Genetic Testing Registry: Deficiency of ferroxidase 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
aceruloplasminemia
What is (are) color vision deficiency ?
Color vision deficiency (sometimes called color blindness) represents a group of conditions that affect the perception of color. Red-green color vision defects are the most common form of color vision deficiency. Affected individuals have trouble distinguishing between some shades of red, yellow, and green. Blue-yellow color vision defects (also called tritan defects), which are rarer, cause problems with differentiating shades of blue and green and cause difficulty distinguishing dark blue from black. These two forms of color vision deficiency disrupt color perception but do not affect the sharpness of vision (visual acuity). A less common and more severe form of color vision deficiency called blue cone monochromacy causes very poor visual acuity and severely reduced color vision. Affected individuals have additional vision problems, which can include increased sensitivity to light (photophobia), involuntary back-and-forth eye movements (nystagmus), and nearsightedness (myopia). Blue cone monochromacy is sometimes considered to be a form of achromatopsia, a disorder characterized by a partial or total lack of color vision with other vision problems.
color vision deficiency
How many people are affected by color vision deficiency ?
Red-green color vision defects are the most common form of color vision deficiency. This condition affects males much more often than females. Among populations with Northern European ancestry, it occurs in about 1 in 12 males and 1 in 200 females. Red-green color vision defects have a lower incidence in almost all other populations studied. Blue-yellow color vision defects affect males and females equally. This condition occurs in fewer than 1 in 10,000 people worldwide. Blue cone monochromacy is rarer than the other forms of color vision deficiency, affecting about 1 in 100,000 people worldwide. Like red-green color vision defects, blue cone monochromacy affects males much more often than females.
color vision deficiency
What are the genetic changes related to color vision deficiency ?
Mutations in the OPN1LW, OPN1MW, and OPN1SW genes cause the forms of color vision deficiency described above. The proteins produced from these genes play essential roles in color vision. They are found in the retina, which is the light-sensitive tissue at the back of the eye. The retina contains two types of light receptor cells, called rods and cones, that transmit visual signals from the eye to the brain. Rods provide vision in low light. Cones provide vision in bright light, including color vision. There are three types of cones, each containing a specific pigment (a photopigment called an opsin) that is most sensitive to particular wavelengths of light. The brain combines input from all three types of cones to produce normal color vision. The OPN1LW, OPN1MW, and OPN1SW genes provide instructions for making the three opsin pigments in cones. The opsin made from the OPN1LW gene is more sensitive to light in the yellow/orange part of the visible spectrum (long-wavelength light), and cones with this pigment are called long-wavelength-sensitive or L cones. The opsin made from the OPN1MW gene is more sensitive to light in the middle of the visible spectrum (yellow/green light), and cones with this pigment are called middle-wavelength-sensitive or M cones. The opsin made from the OPN1SW gene is more sensitive to light in the blue/violet part of the visible spectrum (short-wavelength light), and cones with this pigment are called short-wavelength-sensitive or S cones. Genetic changes involving the OPN1LW or OPN1MW gene cause red-green color vision defects. These changes lead to an absence of L or M cones or to the production of abnormal opsin pigments in these cones that affect red-green color vision. Blue-yellow color vision defects result from mutations in the OPN1SW gene. These mutations lead to the premature destruction of S cones or the production of defective S cones. Impaired S cone function alters perception of the color blue, making it difficult or impossible to detect differences between shades of blue and green and causing problems with distinguishing dark blue from black. Blue cone monochromacy occurs when genetic changes affecting the OPN1LW and OPN1MW genes prevent both L and M cones from functioning normally. In people with this condition, only S cones are functional, which leads to reduced visual acuity and poor color vision. The loss of L and M cone function also underlies the other vision problems in people with blue cone monochromacy. Some problems with color vision are not caused by gene mutations. These nonhereditary conditions are described as acquired color vision deficiencies. They can be caused by other eye disorders, such as diseases involving the retina, the nerve that carries visual information from the eye to the brain (the optic nerve), or areas of the brain involved in processing visual information. Acquired color vision deficiencies can also be side effects of certain drugs, such as chloroquine (which is used to treat malaria), or result from exposure to particular chemicals, such as organic solvents.
color vision deficiency
Is color vision deficiency inherited ?
Red-green color vision defects and blue cone monochromacy are inherited in an X-linked recessive pattern. The OPN1LW and OPN1MW genes are located on the X chromosome, which is one of the two sex chromosomes. In males (who have only one X chromosome), one genetic change in each cell is sufficient to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females because in females (who have two X chromosomes), a genetic change would have to occur on both copies of the chromosome to cause the disorder. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Blue-yellow color vision defects are inherited in an autosomal dominant pattern, which means one copy of the altered OPN1SW gene in each cell is sufficient to cause the condition. In many cases, an affected person inherits the condition from an affected parent.
color vision deficiency
What are the treatments for color vision deficiency ?
These resources address the diagnosis or management of color vision deficiency: - Gene Review: Gene Review: Red-Green Color Vision Defects - Genetic Testing Registry: Colorblindness, partial, deutan series - Genetic Testing Registry: Cone monochromatism - Genetic Testing Registry: Protan defect - Genetic Testing Registry: Red-green color vision defects - Genetic Testing Registry: Tritanopia - MedlinePlus Encyclopedia: Color Vision Test - MedlinePlus Encyclopedia: Colorblind 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
color vision deficiency
What is (are) esophageal atresia/tracheoesophageal fistula ?
Esophageal atresia/tracheoesophageal fistula (EA/TEF) is a condition resulting from abnormal development before birth of the tube that carries food from the mouth to the stomach (the esophagus). During early development, the esophagus and windpipe (trachea) begin as a single tube that normally divides into the two adjacent passages between four and eight weeks after conception. If this separation does not occur properly, EA/TEF is the result. In esophageal atresia (EA), the upper esophagus does not connect (atresia) to the lower esophagus and stomach. Almost 90 percent of babies born with esophageal atresia also have a tracheoesophageal fistula (TEF), in which the esophagus and the trachea are abnormally connected, allowing fluids from the esophagus to get into the airways and interfere with breathing. A small number of infants have only one of these abnormalities. There are several types of EA/TEF, classified by the location of the malformation and the structures that are affected. In more than 80 percent of cases, the lower section of the malformed esophagus is connected to the trachea (EA with a distal TEF). Other possible configurations include having the upper section of the malformed esophagus connected to the trachea (EA with a proximal TEF), connections to the trachea from both the upper and lower sections of the malformed esophagus (EA with proximal and distal TEF), an esophagus that is malformed but does not connect to the trachea (isolated EA), and a connection to the trachea from an otherwise normal esophagus (H-type TEF with no EA). While EA/TEF arises during fetal development, it generally becomes apparent shortly after birth. Saliva, liquids fed to the infant, or digestive fluids may enter the windpipe through the tracheoesophageal fistula, leading to coughing, respiratory distress, and a bluish appearance of the skin or lips (cyanosis). Esophageal atresia blocks liquids fed to the infant from entering the stomach, so they are spit back up, sometimes along with fluids from the respiratory tract. EA/TEF is a life-threatening condition; affected babies generally require surgery to correct the malformation in order to allow feeding and prevent lung damage from repeated exposure to esophageal fluids. EA/TEF occurs alone (isolated EA/TEF) in about 40 percent of affected individuals. In other cases it occurs with other birth defects or as part of a genetic syndrome (non-isolated or syndromic EA/TEF).
esophageal atresia/tracheoesophageal fistula
How many people are affected by esophageal atresia/tracheoesophageal fistula ?
EA/TEF occurs in 1 in 3,000 to 5,000 newborns.
esophageal atresia/tracheoesophageal fistula
What are the genetic changes related to esophageal atresia/tracheoesophageal fistula ?
Isolated EA/TEF is considered to be a multifactorial condition, which means that multiple gene variations and environmental factors likely contribute to its occurrence. In most cases of isolated EA/TEF, no specific genetic changes or environmental factors have been conclusively determined to be the cause. Non-isolated or syndromic forms of EA/TEF can be caused by changes in single genes or in chromosomes, or they can be multifactorial. For example, approximately 10 percent of people with CHARGE syndrome, which is usually caused by mutations in the CHD7 gene, have EA/TEF. About 25 percent of individuals with the chromosomal abnormality trisomy 18 are born with EA/TEF. EA/TEF also occurs in VACTERL association, a multifactorial condition. VACTERL is an acronym that stands for vertebral defects, anal atresia, cardiac defects, tracheoesophageal fistula, renal anomalies, and limb abnormalities. People diagnosed with VACTERL association typically have at least three of these features; between 50 and 80 percent have a tracheoesophageal fistula.
esophageal atresia/tracheoesophageal fistula
Is esophageal atresia/tracheoesophageal fistula inherited ?
When EA/TEF occurs as a feature of a genetic syndrome or chromosomal abnormality, it may cluster in families according to the inheritance pattern for that condition. Often EA/TEF is not inherited, and there is only one affected individual in a family.
esophageal atresia/tracheoesophageal fistula
What are the treatments for esophageal atresia/tracheoesophageal fistula ?
These resources address the diagnosis or management of EA/TEF: - Boston Children's Hospital: Esophageal Atresia - Children's Hospital of Wisconsin - Gene Review: Gene Review: Esophageal Atresia/Tracheoesophageal Fistula Overview - Genetic Testing Registry: Tracheoesophageal fistula - MedlinePlus Encyclopedia: Tracheoesophageal Fistula and Esophageal Atresia Repair - University of California, San Francisco (UCSF) Medical Center 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
esophageal atresia/tracheoesophageal fistula
What is (are) epidermolytic hyperkeratosis ?
Epidermolytic hyperkeratosis is a skin disorder that is present at birth. Affected babies may have very red skin (erythroderma) and severe blisters. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis). As affected individuals get older, blistering is less frequent, erythroderma becomes less evident, and the skin becomes thick (hyperkeratotic), especially over joints, on areas of skin that come into contact with each other, or on the scalp or neck. This thickened skin is usually darker than normal. Bacteria can grow in the thick skin, often causing a distinct odor. Epidermolytic hyperkeratosis can be categorized into two types. People with PS-type epidermolytic hyperkeratosis have thick skin on the palms of their hands and soles of their feet (palmoplantar or palm/sole hyperkeratosis) in addition to other areas of the body. People with the other type, NPS-type, do not have extensive palmoplantar hyperkeratosis but do have hyperkeratosis on other areas of the body. Epidermolytic hyperkeratosis is part of a group of conditions called ichthyoses, which refers to the scaly skin seen in individuals with related disorders. However, in epidermolytic hyperkeratosis, the skin is thick but not scaly as in some of the other conditions in the group.
epidermolytic hyperkeratosis
How many people are affected by epidermolytic hyperkeratosis ?
Epidermolytic hyperkeratosis affects approximately 1 in 200,000 to 300,000 people worldwide.
epidermolytic hyperkeratosis
What are the genetic changes related to epidermolytic hyperkeratosis ?
Mutations in the KRT1 or KRT10 genes are responsible for epidermolytic hyperkeratosis. These genes provide instructions for making proteins called keratin 1 and keratin 10, which are found in cells called keratinocytes in the outer layer of the skin (the epidermis). The tough, fibrous keratin proteins attach to each other and form fibers called intermediate filaments, which form networks and provide strength and resiliency to the epidermis. Mutations in the KRT1 or KRT10 genes lead to changes in the keratin proteins, preventing them from forming strong, stable intermediate filament networks within cells. Without a strong network, keratinocytes become fragile and are easily damaged, which can lead to blistering in response to friction or mild trauma. It is unclear how these mutations cause the overgrowth of epidermal cells that results in hyperkeratotic skin. KRT1 gene mutations are associated with PS-type epidermal hyperkeratosis, and KRT10 gene mutations are usually associated with NPS-type. The keratin 1 protein is present in the keratinocytes of the skin on the palms of the hands and the soles of the feet as well as other parts of the body, so mutations in the KRT1 gene lead to skin problems in these areas. The keratin 10 protein is not found in the skin of the palms and soles, so these areas are unaffected by mutations in the KRT10 gene.
epidermolytic hyperkeratosis
Is epidermolytic hyperkeratosis inherited ?
Epidermolytic hyperkeratosis can have different inheritance patterns. About half of the cases of this condition result from new mutations in the KRT1 or KRT10 gene and occur in people with no history of the disorder in their family. When epidermolytic hyperkeratosis is inherited, it is usually in an autosomal dominant pattern, which means one copy of the altered KRT1 or KRT10 gene in each cell is sufficient to cause the disorder. Very rarely, epidermolytic hyperkeratosis caused by mutations in the KRT10 gene can be 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.
epidermolytic hyperkeratosis
What are the treatments for epidermolytic hyperkeratosis ?
These resources address the diagnosis or management of epidermolytic hyperkeratosis: - Genetic Testing Registry: Bullous ichthyosiform erythroderma - The Swedish Information Centre for Rare Diseases: Ichthyosis 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
epidermolytic hyperkeratosis
What is (are) Crouzon syndrome ?
Crouzon syndrome is a genetic disorder characterized by the premature fusion of certain skull bones (craniosynostosis). This early fusion prevents the skull from growing normally and affects the shape of the head and face. Many features of Crouzon syndrome result from the premature fusion of the skull bones. Abnormal growth of these bones leads to wide-set, bulging eyes and vision problems caused by shallow eye sockets; eyes that do not point in the same direction (strabismus); a beaked nose; and an underdeveloped upper jaw. In addition, people with Crouzon syndrome may have dental problems and hearing loss, which is sometimes accompanied by narrow ear canals. A few people with Crouzon syndrome have an opening in the lip and the roof of the mouth (cleft lip and palate). The severity of these signs and symptoms varies among affected people. People with Crouzon syndrome are usually of normal intelligence.
Crouzon syndrome
How many people are affected by Crouzon syndrome ?
Crouzon syndrome is seen in about 16 per million newborns. It is the most common craniosynostosis syndrome.
Crouzon syndrome
What are the genetic changes related to Crouzon syndrome ?
Mutations in the FGFR2 gene cause Crouzon syndrome. This gene provides instructions for making a protein called fibroblast growth factor receptor 2. Among its multiple functions, this protein signals immature cells to become bone cells during embryonic development. Mutations in the FGFR2 gene probably overstimulate signaling by the FGFR2 protein, which causes the bones of the skull to fuse prematurely.
Crouzon syndrome
Is Crouzon 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.
Crouzon syndrome
What are the treatments for Crouzon syndrome ?
These resources address the diagnosis or management of Crouzon syndrome: - Gene Review: Gene Review: FGFR-Related Craniosynostosis Syndromes - Genetic Testing Registry: Crouzon syndrome - MedlinePlus Encyclopedia: Craniosynostosis 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
Crouzon syndrome
What is (are) uromodulin-associated kidney disease ?
Uromodulin-associated kidney disease is an inherited condition that affects the kidneys. The signs and symptoms of this condition vary, even among members of the same family. Many individuals with uromodulin-associated kidney disease develop high blood levels of a waste product called uric acid. Normally, the kidneys remove uric acid from the blood and transfer it to urine. In this condition, the kidneys are unable to remove uric acid from the blood effectively. A buildup of uric acid can cause gout, which is a form of arthritis resulting from uric acid crystals in the joints. The signs and symptoms of gout may appear as early as a person's teens in uromodulin-associated kidney disease. Uromodulin-associated kidney disease causes slowly progressive kidney disease, with the signs and symptoms usually beginning during the teenage years. The kidneys become less able to filter fluids and waste products from the body as this condition progresses, resulting in kidney failure. Individuals with uromodulin-associated kidney disease typically require either dialysis to remove wastes from the blood or a kidney transplant between the ages of 30 and 70. Occasionally, affected individuals are found to have small kidneys or kidney cysts (medullary cysts).
uromodulin-associated kidney disease
How many people are affected by uromodulin-associated kidney disease ?
The prevalence of uromodulin-associated kidney disease is unknown. It accounts for fewer than 1 percent of cases of kidney disease.
uromodulin-associated kidney disease
What are the genetic changes related to uromodulin-associated kidney disease ?
Mutations in the UMOD gene cause uromodulin-associated kidney disease. This gene provides instructions for making the uromodulin protein, which is produced by the kidneys and then excreted from the body in urine. The function of uromodulin remains unclear, although it is known to be the most abundant protein in the urine of healthy individuals. Researchers have suggested that uromodulin may protect against urinary tract infections. It may also help control the amount of water in urine. Most mutations in the UMOD gene change single protein building blocks (amino acids) used to make uromodulin. These mutations alter the structure of the protein, preventing its release from kidney cells. Abnormal buildup of uromodulin may trigger the self-destruction (apoptosis) of cells in the kidneys, causing progressive kidney disease.
uromodulin-associated kidney disease
Is uromodulin-associated kidney disease 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.
uromodulin-associated kidney disease
What are the treatments for uromodulin-associated kidney disease ?
These resources address the diagnosis or management of uromodulin-associated kidney disease: - Gene Review: Gene Review: Autosomal Dominant Tubulointerstitial Kidney Disease, UMOD-Related (ADTKD-UMOD) - Genetic Testing Registry: Familial juvenile gout - Genetic Testing Registry: Glomerulocystic kidney disease with hyperuricemia and isosthenuria - Genetic Testing Registry: Medullary cystic kidney disease 2 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
uromodulin-associated kidney disease
What is (are) congenital fiber-type disproportion ?
Congenital fiber-type disproportion is a condition that primarily affects skeletal muscles, which are muscles used for movement. People with this condition typically experience muscle weakness (myopathy), particularly in the muscles of the shoulders, upper arms, hips, and thighs. Weakness can also affect the muscles of the face and muscles that control eye movement (ophthalmoplegia), sometimes causing droopy eyelids (ptosis). Individuals with congenital fiber-type disproportion generally have a long face, a high arch in the roof of the mouth (high-arched palate), and crowded teeth. Affected individuals may have joint deformities (contractures) and an abnormally curved lower back (lordosis) or a spine that curves to the side (scoliosis). Approximately 30 percent of people with this disorder experience mild to severe breathing problems related to weakness of muscles needed for breathing. Some people who experience these breathing problems require use of a machine to help regulate their breathing at night (noninvasive mechanical ventilation), and occasionally during the day as well. About 30 percent of affected individuals have difficulty swallowing due to muscle weakness in the throat. Rarely, people with this condition have a weakened and enlarged heart muscle (dilated cardiomyopathy). The severity of congenital fiber-type disproportion varies widely. It is estimated that up to 25 percent of affected individuals experience severe muscle weakness at birth and die in infancy or childhood. Others have only mild muscle weakness that becomes apparent in adulthood. Most often, the signs and symptoms of this condition appear by age 1. The first signs of this condition are usually decreased muscle tone (hypotonia) and muscle weakness. In most cases, muscle weakness does not worsen over time, and in some instances it may improve. Although motor skills such as standing and walking may be delayed, many affected children eventually learn to walk. These individuals often have less stamina than their peers, but they remain active. Rarely, people with this condition have a progressive decline in muscle strength over time. These individuals may lose the ability to walk and require wheelchair assistance.
congenital fiber-type disproportion
How many people are affected by congenital fiber-type disproportion ?
Congenital fiber-type disproportion is thought to be a rare condition, although its prevalence is unknown.
congenital fiber-type disproportion
What are the genetic changes related to congenital fiber-type disproportion ?
Mutations in multiple genes can cause congenital fiber-type disproportion. Mutations in the TPM3, RYR1 and ACTA1 genes cause 35 to 50 percent of cases, while mutations in other genes, some known and some unidentified, are responsible for the remaining cases. The genes that cause congenital fiber-type disproportion provide instructions for making proteins that are involved in the tensing of muscle fibers (muscle contraction). Changes in these proteins lead to impaired muscle contraction, resulting in muscle weakness. Skeletal muscle is made up of two types of muscle fibers: type I (slow twitch fibers) and type II (fast twitch fibers). Normally, type I and type II fibers are the same size. In people with congenital fiber-type disproportion, type I skeletal muscle fibers are significantly smaller than type II skeletal muscle fibers. It is unclear whether the small type I skeletal muscle fibers lead to muscle weakness or are caused by muscle weakness in people with congenital fiber-type disproportion.
congenital fiber-type disproportion
Is congenital fiber-type disproportion inherited ?
Congenital fiber-type disproportion can have multiple inheritance patterns. When this condition is caused by mutations in the ACTA1 gene, it usually occurs in an autosomal dominant pattern. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. Most other cases of congenital fiber-type disproportion, including those caused by mutations in the RYR1 gene, have an autosomal recessive pattern of inheritance. 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. When this condition is caused by mutations in the TPM3 gene, it can occur in either an autosomal dominant or autosomal recessive pattern. In rare cases, this condition can be inherited in an X-linked pattern, although the gene or genes associated with X-linked congenital fiber-type disproportion have not been identified. 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 each cell. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. Because females have two copies of the X chromosome, one altered copy of the gene in each cell usually leads to less severe symptoms in females than in males or may cause no symptoms at all. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. It is estimated that 40 percent of individuals with congenital fiber-type disproportion have an affected relative.
congenital fiber-type disproportion
What are the treatments for congenital fiber-type disproportion ?
These resources address the diagnosis or management of congenital fiber-type disproportion: - Gene Review: Gene Review: Congenital Fiber-Type Disproportion - Genetic Testing Registry: Congenital myopathy with fiber type disproportion - MedlinePlus Encyclopedia: Contracture Deformity - MedlinePlus Encyclopedia: Hypotonia 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
congenital fiber-type disproportion
What is (are) polymicrogyria ?
Polymicrogyria is a condition characterized by abnormal development of the brain before birth. The surface of the brain normally has many ridges or folds, called gyri. In people with polymicrogyria, the brain develops too many folds, and the folds are unusually small. The name of this condition literally means too many (poly-) small (micro-) folds (-gyria) in the surface of the brain. Polymicrogyria can affect part of the brain or the whole brain. When the condition affects one side of the brain, researchers describe it as unilateral. When it affects both sides of the brain, it is described as bilateral. The signs and symptoms associated with polymicrogyria depend on how much of the brain, and which particular brain regions, are affected. Researchers have identified multiple forms of polymicrogyria. The mildest form is known as unilateral focal polymicrogyria. This form of the condition affects a relatively small area on one side of the brain. It may cause minor neurological problems, such as mild seizures that can be easily controlled with medication. Some people with unilateral focal polymicrogyria do not have any problems associated with the condition. Bilateral forms of polymicrogyria tend to cause more severe neurological problems. Signs and symptoms of these conditions can include recurrent seizures (epilepsy), delayed development, crossed eyes, problems with speech and swallowing, and muscle weakness or paralysis. The most severe form of the disorder, bilateral generalized polymicrogyria, affects the entire brain. This condition causes severe intellectual disability, problems with movement, and seizures that are difficult or impossible to control with medication. Polymicrogyria most often occurs as an isolated feature, although it can occur with other brain abnormalities. It is also a feature of several genetic syndromes characterized by intellectual disability and multiple birth defects. These include 22q11.2 deletion syndrome, Adams-Oliver syndrome, Aicardi syndrome, Galloway-Mowat syndrome, Joubert syndrome, and Zellweger spectrum disorder.
polymicrogyria
How many people are affected by polymicrogyria ?
The prevalence of isolated polymicrogyria is unknown. Researchers believe that it may be relatively common overall, although the individual forms of the disorder (such as bilateral generalized polymicrogyria) are probably rare.
polymicrogyria
What are the genetic changes related to polymicrogyria ?
In most people with polymicrogyria, the cause of the condition is unknown. However, researchers have identified several environmental and genetic factors that can be responsible for the disorder. Environmental causes of polymicrogyria include certain infections during pregnancy and a lack of oxygen to the fetus (intrauterine ischemia). Researchers are investigating the genetic causes of polymicrogyria. The condition can result from deletions or rearrangements of genetic material from several different chromosomes. Additionally, mutations in one gene, ADGRG1, have been found to cause a severe form of the condition called bilateral frontoparietal polymicrogyria (BFPP). The ADGRG1 gene appears to be critical for the normal development of the outer layer of the brain. Researchers believe that many other genes are probably involved in the different forms of polymicrogyria.
polymicrogyria
Is polymicrogyria inherited ?
Isolated polymicrogyria can have different inheritance patterns. Several forms of the condition, including bilateral frontoparietal polymicrogyria (which is associated with mutations in the ADGRG1 gene), have an autosomal recessive pattern of inheritance. In autosomal recessive inheritance, 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. Polymicrogyria can also have an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Other forms of polymicrogyria appear to have an X-linked pattern of inheritance. Genes associated with X-linked conditions are located on the X chromosome, which is one of the two sex chromosomes. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Some people with polymicrogyria have relatives with the disorder, while other affected individuals have no family history of the condition. When an individual is the only affected person in his or her family, it can be difficult to determine the cause and possible inheritance pattern of the disorder.
polymicrogyria
What are the treatments for polymicrogyria ?
These resources address the diagnosis or management of polymicrogyria: - Gene Review: Gene Review: Polymicrogyria Overview - Genetic Testing Registry: Congenital bilateral perisylvian syndrome - Genetic Testing Registry: Polymicrogyria, asymmetric - Genetic Testing Registry: Polymicrogyria, bilateral frontoparietal - Genetic Testing Registry: Polymicrogyria, bilateral occipital 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
polymicrogyria
What is (are) Cant syndrome ?
Cant syndrome is a rare condition characterized by excess hair growth (hypertrichosis), a distinctive facial appearance, heart defects, and several other abnormalities. The features of the disorder vary among affected individuals. People with Cant syndrome have thick scalp hair that extends onto the forehead and grows down onto the cheeks in front of the ears. They also have increased body hair, especially on the back, arms, and legs. Most affected individuals have a large head (macrocephaly) and distinctive facial features that are described as "coarse." These include a broad nasal bridge, skin folds covering the inner corner of the eyes (epicanthal folds), and a wide mouth with full lips. As affected individuals get older, the face lengthens, the chin becomes more prominent, and the eyes become deep-set. Many infants with Cant syndrome are born with a heart defect such as an enlarged heart (cardiomegaly) or patent ductus arteriosus (PDA). The ductus arteriosus is a connection between two major arteries, the aorta and the pulmonary artery. This connection is open during fetal development and normally closes shortly after birth. However, the ductus arteriosus remains open, or patent, in babies with PDA. Other heart problems have also been found in people with Cant syndrome, including an abnormal buildup of fluid around the heart (pericardial effusion) and high blood pressure in the blood vessels that carry blood from the heart to the lungs (pulmonary hypertension). Additional features of this condition include distinctive skeletal abnormalities, a large body size (macrosomia) at birth, a reduced amount of fat under the skin (subcutaneous fat) beginning in childhood, deep horizontal creases in the palms of the hands and soles of the feet, and an increased susceptibility to respiratory infections. Other signs and symptoms that have been reported include abnormal swelling in the body's tissues (lymphedema), side-to-side curvature of the spine (scoliosis), and reduced bone density (osteopenia). Some affected children have weak muscle tone (hypotonia) that delays the development of motor skills such as sitting, standing, and walking. Most have mildly delayed speech, and some affected children have mild intellectual disability or learning problems.
Cant syndrome
How many people are affected by Cant syndrome ?
Cant syndrome is a rare condition. About three dozen affected individuals have been reported in the medical literature.
Cant syndrome
What are the genetic changes related to Cant syndrome ?
Cant syndrome results from mutations in the ABCC9 gene. This gene provides instructions for making one part (subunit) of a channel that transports charged potassium atoms (potassium ions) across cell membranes. Mutations in the ABCC9 gene alter the structure of the potassium channel, which causes the channel to open when it should be closed. It is unknown how this problem with potassium channel function leads to excess hair growth, heart defects, and the other features of Cant syndrome.
Cant syndrome
Is Cant syndrome inherited ?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered ABCC9 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. In a few reported cases, an affected person has inherited the mutation from one affected parent.
Cant syndrome
What are the treatments for Cant syndrome ?
These resources address the diagnosis or management of Cant syndrome: - Gene Review: Gene Review: Cant syndrome - Genetic Testing Registry: Hypertrichotic osteochondrodysplasia 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
Cant syndrome
What is (are) microphthalmia ?
Microphthalmia is an eye abnormality that arises before birth. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss. People with microphthalmia may also have a condition called coloboma. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or in the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision. People with microphthalmia may also have other eye abnormalities, including clouding of the lens of the eye (cataract) and a narrowed opening of the eye (narrowed palpebral fissure). Additionally, affected individuals may have an abnormality called microcornea, in which the clear front covering of the eye (cornea) is small and abnormally curved. Between one-third and one-half of affected individuals have microphthalmia as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When microphthalmia occurs by itself, it is described as nonsyndromic or isolated.
microphthalmia
How many people are affected by microphthalmia ?
Microphthalmia occurs in approximately 1 in 10,000 individuals.
microphthalmia
What are the genetic changes related to microphthalmia ?
Microphthalmia may be caused by changes in many genes involved in the early development of the eye, most of which have not been identified. The condition may also result from a chromosomal abnormality affecting one or more genes. Most genetic changes associated with isolated microphthalmia have been identified only in very small numbers of affected individuals. Microphthalmia may also be caused by environmental factors that affect early development, such as a shortage of certain vitamins during pregnancy, radiation, infections such as rubella, or exposure to substances that cause birth defects (teratogens).
microphthalmia
Is microphthalmia inherited ?
Isolated microphthalmia is sometimes 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. In some cases, parents of affected individuals have less severe eye abnormalities. When microphthalmia occurs as a feature of a genetic syndrome or chromosomal abnormality, it may cluster in families according to the inheritance pattern for that condition, which may be autosomal recessive or other patterns. Often microphthalmia is not inherited, and there is only one affected individual in a family.
microphthalmia
What are the treatments for microphthalmia ?
These resources address the diagnosis or management of microphthalmia: - Gene Review: Gene Review: Microphthalmia/Anophthalmia/Coloboma Spectrum - Genetic Testing Registry: Cataract, congenital, with microphthalmia - Genetic Testing Registry: Cataract, microphthalmia and nystagmus - Genetic Testing Registry: Microphthalmia, isolated 1 - Genetic Testing Registry: Microphthalmia, isolated 2 - Genetic Testing Registry: Microphthalmia, isolated 3 - Genetic Testing Registry: Microphthalmia, isolated 4 - Genetic Testing Registry: Microphthalmia, isolated 5 - Genetic Testing Registry: Microphthalmia, isolated 6 - Genetic Testing Registry: Microphthalmia, isolated 7 - Genetic Testing Registry: Microphthalmia, isolated 8 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 1 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 2 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 3 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 4 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 5 - Genetic Testing Registry: Microphthalmia, isolated, with coloboma 6 - Genetic Testing Registry: Microphthalmia, isolated, with corectopia - Genetic Testing Registry: Microphthalmos 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
microphthalmia
What is (are) chorea-acanthocytosis ?
Chorea-acanthocytosis is primarily a neurological disorder that affects movement in many parts of the body. Chorea refers to the involuntary jerking movements made by people with this disorder. People with this condition also have abnormal star-shaped red blood cells (acanthocytosis). This condition is one of a group of conditions called neuroacanthocytoses that involve neurological problems and abnormal red blood cells. In addition to chorea, another common feature of chorea-acanthocytosis is involuntary tensing of various muscles (dystonia), such as those in the limbs, face, mouth, tongue, and throat. These muscle twitches can cause vocal tics (such as grunting), involuntary belching, and limb spasms. Eating can also be impaired as tongue and throat twitches can interfere with chewing and swallowing food. People with chorea-acanthocytosis may uncontrollably bite their tongue, lips, and inside of the mouth. Nearly half of all people with chorea-acanthocytosis have seizures. Individuals with chorea-acanthocytosis may develop difficulty processing, learning, and remembering information (cognitive impairment). They may have reduced sensation and weakness in their arms and legs (peripheral neuropathy) and muscle weakness (myopathy). Impaired muscle and nerve functioning commonly cause speech difficulties in individuals with this condition, and can lead to an inability to speak. Behavioral changes are a common feature of chorea-acanthocytosis and may be the first sign of this condition. These behavioral changes may include changes in personality, obsessive-compulsive disorder (OCD), lack of self-restraint, and the inability to take care of oneself. The signs and symptoms of chorea-acanthocytosis usually begin in early to mid-adulthood. The movement problems of this condition worsen with age. Loss of cells (atrophy) in certain brain regions is the major cause of the neurological problems seen in people with chorea-acanthocytosis.
chorea-acanthocytosis
How many people are affected by chorea-acanthocytosis ?
It is estimated that 500 to 1,000 people worldwide have chorea-acanthocytosis.
chorea-acanthocytosis
What are the genetic changes related to chorea-acanthocytosis ?
Mutations in the VPS13A gene cause chorea-acanthocytosis. The VPS13A gene provides instructions for producing a protein called chorein; the function of this protein in the body is unknown. Some researchers believe that chorein plays a role in the movement of proteins within cells. Most VPS13A gene mutations lead to the production of an abnormally small, nonfunctional version of chorein. The VPS13A gene is active (expressed) throughout the body; it is unclear why mutations in this gene affect only the brain and red blood cells.
chorea-acanthocytosis
Is chorea-acanthocytosis 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.
chorea-acanthocytosis
What are the treatments for chorea-acanthocytosis ?
These resources address the diagnosis or management of chorea-acanthocytosis: - Gene Review: Gene Review: Chorea-Acanthocytosis - Genetic Testing Registry: Choreoacanthocytosis 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
chorea-acanthocytosis
What is (are) Rett syndrome ?
Rett syndrome is a brain disorder that occurs almost exclusively in girls. The most common form of the condition is known as classic Rett syndrome. After birth, girls with classic Rett syndrome have 6 to 18 months of apparently normal development before developing severe problems with language and communication, learning, coordination, and other brain functions. Early in childhood, affected girls lose purposeful use of their hands and begin making repeated hand wringing, washing, or clapping motions. They tend to grow more slowly than other children and have a small head size (microcephaly). Other signs and symptoms that can develop include breathing abnormalities, seizures, an abnormal side-to-side curvature of the spine (scoliosis), and sleep disturbances. Researchers have described several variant or atypical forms of Rett syndrome, which can be milder or more severe than the classic form.
Rett syndrome
How many people are affected by Rett syndrome ?
This condition affects an estimated 1 in 8,500 females.
Rett syndrome
What are the genetic changes related to Rett syndrome ?
Classic Rett syndrome and some variant forms of the condition are caused by mutations in the MECP2 gene. This gene provides instructions for making a protein (MeCP2) that is critical for normal brain function. Although the exact function of the MeCP2 protein is unclear, it is likely involved in maintaining connections (synapses) between nerve cells (neurons). It may also be necessary for the normal function of other types of brain cells. The MeCP2 protein is thought to help regulate the activity of genes in the brain. This protein may also control the production of different versions of certain proteins in brain cells. Mutations in the MECP2 gene alter the MeCP2 protein or result in the production of less protein, which appears to disrupt the normal function of neurons and other cells in the brain. Specifically, studies suggest that changes in the MeCP2 protein may reduce the activity of certain neurons and impair their ability to communicate with one another. It is unclear how these changes lead to the specific features of Rett syndrome. Several conditions with signs and symptoms overlapping those of Rett syndrome have been found to result from mutations in other genes. These conditions, including FOXG1 syndrome, were previously thought to be variant forms of Rett syndrome. However, doctors and researchers have identified some important differences between the conditions, so they are now usually considered to be separate disorders.
Rett syndrome
Is Rett syndrome inherited ?
In more than 99 percent of people with Rett syndrome, there is no history of the disorder in their family. Many of these cases result from new mutations in the MECP2 gene. A few families with more than one affected family member have been described. These cases helped researchers determine that classic Rett syndrome and variants caused by MECP2 gene mutations have an X-linked dominant pattern of inheritance. 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. Males with mutations in the MECP2 gene often die in infancy. However, a small number of males with a genetic change involving MECP2 have developed signs and symptoms similar to those of Rett syndrome, including intellectual disability, seizures, and movement problems. In males, this condition is described as MECP2-related severe neonatal encephalopathy.
Rett syndrome
What are the treatments for Rett syndrome ?
These resources address the diagnosis or management of Rett syndrome: - Boston Children's Hospital - Cleveland Clinic - Gene Review: Gene Review: MECP2-Related Disorders - Genetic Testing Registry: Rett syndrome - International Rett Syndrome Foundation: Living with Rett Syndrome - MedlinePlus Encyclopedia: Rett 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
Rett syndrome
What is (are) Y chromosome infertility ?
Y chromosome infertility is a condition that affects the production of sperm, making it difficult or impossible for affected men to father children. An affected man's body may produce no sperm cells (azoospermia), a smaller than usual number of sperm cells (oligospermia), or sperm cells that are abnormally shaped or that do not move properly. Some men with Y chromosome infertility who have mild to moderate oligospermia may eventually father a child naturally. Assisted reproductive technologies may help other affected men; most men with Y chromosome infertility have some sperm cells in the testes that can be extracted for this purpose. The most severely affected men do not have any mature sperm cells in the testes. This form of Y chromosome infertility is called Sertoli cell-only syndrome. Men with Y chromosome infertility usually do not have any other signs or symptoms. Occasionally they may have unusually small testes or undescended testes (cryptorchidism).
Y chromosome infertility
How many people are affected by Y chromosome infertility ?
Y chromosome infertility occurs in approximately 1 in 2,000 to 1 in 3,000 males of all ethnic groups. This condition accounts for between 5 percent and 10 percent of cases of azoospermia or severe oligospermia.
Y chromosome infertility
What are the genetic changes related to Y chromosome infertility ?
As its name suggests, this form of infertility is caused by changes in the Y chromosome. People normally have 46 chromosomes in each cell. Two of the 46 chromosomes are sex chromosomes, called X and Y. Females have two X chromosomes (46,XX), and males have one X chromosome and one Y chromosome (46,XY). Because only males have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and development. Y chromosome infertility is usually caused by deletions of genetic material in regions of the Y chromosome called azoospermia factor (AZF) A, B, or C. Genes in these regions are believed to provide instructions for making proteins involved in sperm cell development, although the specific functions of these proteins are not well understood. Deletions in the AZF regions may affect several genes. The missing genetic material likely prevents production of a number of proteins needed for normal sperm cell development, resulting in Y chromosome infertility. In rare cases, changes to a single gene called USP9Y, which is located in the AZFA region of the Y chromosome, can cause Y chromosome infertility. The USP9Y gene provides instructions for making a protein called ubiquitin-specific protease 9. A small number of individuals with Y chromosome infertility have deletions of all or part of the USP9Y gene, while other genes in the AZF regions are unaffected. Deletions in the USP9Y gene prevent the production of ubiquitin-specific protease 9 or result in the production of an abnormally short, nonfunctional protein. The absence of functional ubiquitin-specific protease 9 impairs the production of sperm cells, resulting in Y chromosome infertility.
Y chromosome infertility
Is Y chromosome infertility inherited ?
Because Y chromosome infertility impedes the ability to father children, this condition is usually caused by new deletions on the Y chromosome and occurs in men with no history of the disorder in their family. When men with Y chromosome infertility do father children, either naturally or with the aid of assisted reproductive technologies, they pass on the genetic changes on the Y chromosome to all their sons. As a result, the sons will also have Y chromosome infertility. This form of inheritance is called Y-linked. Daughters, who do not inherit the Y chromosome, are not affected.
Y chromosome infertility
What are the treatments for Y chromosome infertility ?
These resources address the diagnosis or management of Y chromosome infertility: - Gene Review: Gene Review: Y Chromosome Infertility - Genetic Testing Registry: Spermatogenic failure, Y-linked 2 - Genetic Testing Registry: Spermatogenic failure, Y-linked, 1 - MedlinePlus Encyclopedia: Semen Analysis 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
Y chromosome infertility
What is (are) aspartylglucosaminuria ?
Aspartylglucosaminuria is a condition that causes a progressive decline in mental functioning. Infants with aspartylglucosaminuria appear healthy at birth, and development is typically normal throughout early childhood. The first sign of this condition, evident around the age of 2 or 3, is usually delayed speech. Mild intellectual disability then becomes apparent, and learning occurs at a slowed pace. Intellectual disability progressively worsens in adolescence. Most people with this disorder lose much of the speech they have learned, and affected adults usually have only a few words in their vocabulary. Adults with aspartylglucosaminuria may develop seizures or problems with movement. People with this condition may also have bones that become progressively weak and prone to fracture (osteoporosis), an unusually large range of joint movement (hypermobility), and loose skin. Affected individuals tend to have a characteristic facial appearance that includes widely spaced eyes (ocular hypertelorism), small ears, and full lips. The nose is short and broad and the face is usually square-shaped. Children with this condition may be tall for their age, but lack of a growth spurt in puberty typically causes adults to be short. Affected children also tend to have frequent upper respiratory infections. Individuals with aspartylglucosaminuria usually survive into mid-adulthood.
aspartylglucosaminuria
How many people are affected by aspartylglucosaminuria ?
Aspartylglucosaminuria is estimated to affect 1 in 18,500 people in Finland. This condition is less common outside of Finland, but the incidence is unknown.
aspartylglucosaminuria
What are the genetic changes related to aspartylglucosaminuria ?
Mutations in the AGA gene cause aspartylglucosaminuria. The AGA gene provides instructions for producing an enzyme called aspartylglucosaminidase. This enzyme is active in lysosomes, which are structures inside cells that act as recycling centers. Within lysosomes, the enzyme helps break down complexes of sugar molecules (oligosaccharides) attached to certain proteins (glycoproteins). AGA gene mutations result in the absence or shortage of the aspartylglucosaminidase enzyme in lysosomes, preventing the normal breakdown of glycoproteins. As a result, glycoproteins can build up within the lysosomes. Excess glycoproteins disrupt the normal functions of the cell and can result in destruction of the cell. A buildup of glycoproteins seems to particularly affect nerve cells in the brain; loss of these cells causes many of the signs and symptoms of aspartylglucosaminuria.
aspartylglucosaminuria
Is aspartylglucosaminuria 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.
aspartylglucosaminuria
What are the treatments for aspartylglucosaminuria ?
These resources address the diagnosis or management of aspartylglucosaminuria: - Genetic Testing Registry: Aspartylglycosaminuria 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
aspartylglucosaminuria
What is (are) Treacher Collins syndrome ?
Treacher Collins syndrome is a condition that affects the development of bones and other tissues of the face. The signs and symptoms of this disorder vary greatly, ranging from almost unnoticeable to severe. Most affected individuals have underdeveloped facial bones, particularly the cheek bones, and a very small jaw and chin (micrognathia). Some people with this condition are also born with an opening in the roof of the mouth called a cleft palate. In severe cases, underdevelopment of the facial bones may restrict an affected infant's airway, causing potentially life-threatening respiratory problems. People with Treacher Collins syndrome often have eyes that slant downward, sparse eyelashes, and a notch in the lower eyelids called an eyelid coloboma. Some affected individuals have additional eye abnormalities that can lead to vision loss. This condition is also characterized by absent, small, or unusually formed ears. Hearing loss occurs in about half of all affected individuals; hearing loss is caused by defects of the three small bones in the middle ear, which transmit sound, or by underdevelopment of the ear canal. People with Treacher Collins syndrome usually have normal intelligence.
Treacher Collins syndrome
How many people are affected by Treacher Collins syndrome ?
This condition affects an estimated 1 in 50,000 people.
Treacher Collins syndrome
What are the genetic changes related to Treacher Collins syndrome ?
Mutations in the TCOF1, POLR1C, or POLR1D gene can cause Treacher Collins syndrome. TCOF1 gene mutations are the most common cause of the disorder, accounting for 81 to 93 percent of all cases. POLR1C and POLR1D gene mutations cause an additional 2 percent of cases. In individuals without an identified mutation in one of these genes, the genetic cause of the condition is unknown. The proteins produced from the TCOF1, POLR1C, and POLR1D genes all appear to play important roles in the early development of bones and other tissues of the face. These proteins are involved in the production of a molecule called ribosomal RNA (rRNA), a chemical cousin of DNA. Ribosomal RNA helps assemble protein building blocks (amino acids) into new proteins, which is essential for the normal functioning and survival of cells. Mutations in the TCOF1, POLR1C, or POLR1D gene reduce the production of rRNA. Researchers speculate that a decrease in the amount of rRNA may trigger the self-destruction (apoptosis) of certain cells involved in the development of facial bones and tissues. The abnormal cell death could lead to the specific problems with facial development found in Treacher Collins syndrome. However, it is unclear why the effects of a reduction in rRNA are limited to facial development.
Treacher Collins syndrome
Is Treacher Collins syndrome inherited ?
When Treacher Collins syndrome results from mutations in the TCOF1 or POLR1D gene, it is considered an autosomal dominant condition, which means one copy of the altered gene in each cell is sufficient to cause the disorder. About 60 percent of these cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In the remaining autosomal dominant cases, a person with Treacher Collins syndrome inherits the altered gene from an affected parent. When Treacher Collins syndrome is caused by mutations in the POLR1C gene, the condition has an autosomal recessive pattern of inheritance. 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.
Treacher Collins syndrome
What are the treatments for Treacher Collins syndrome ?
These resources address the diagnosis or management of Treacher Collins syndrome: - Gene Review: Gene Review: Treacher Collins Syndrome - Genetic Testing Registry: Mandibulofacial dysostosis, Treacher Collins type, autosomal recessive - Genetic Testing Registry: Treacher Collins syndrome - Genetic Testing Registry: Treacher collins syndrome 1 - Genetic Testing Registry: Treacher collins syndrome 2 - MedlinePlus Encyclopedia: Micrognathia - MedlinePlus Encyclopedia: Pinna Abnormalities and Low-Set Ears - MedlinePlus Encyclopedia: Treacher-Collins 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
Treacher Collins syndrome
What is (are) familial pityriasis rubra pilaris ?
Familial pityriasis rubra pilaris is a rare genetic condition that affects the skin. The name of the condition reflects its major features: The term "pityriasis" refers to scaling; "rubra" means redness; and "pilaris" suggests the involvement of hair follicles in this disorder. Affected individuals have a salmon-colored skin rash covered in fine scales. This rash occurs in patches all over the body, with distinct areas of unaffected skin between the patches. Affected individuals also develop bumps called follicular keratoses that occur around hair follicles. 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. Researchers have distinguished six types of pityriasis rubra pilaris based on the features of the disorder and the age at which signs and symptoms appear. The familial form is usually considered part of type V, which is also known as the atypical juvenile type. People with familial pityriasis rubra pilaris typically have skin abnormalities from birth or early childhood, and these skin problems persist throughout life.
familial pityriasis rubra pilaris
How many people are affected by familial pityriasis rubra pilaris ?
Familial pityriasis rubra pilaris is a rare condition. Its incidence is unknown, although the familial form appears to be the least common type of pityriasis rubra pilaris.
familial pityriasis rubra pilaris
What are the genetic changes related to familial pityriasis rubra pilaris ?
In most cases of pityriasis rubra pilaris, the cause of the condition is unknown. However, mutations in the CARD14 gene have been found to cause the familial form of the disorder in a few affected families. The CARD14 gene provides instructions for making a protein that turns on (activates) a group of interacting proteins known as nuclear factor-kappa-B (NF-B). NF-B regulates the activity of multiple genes, including genes that control the body's immune responses and inflammatory reactions. It also protects cells from certain signals that would otherwise cause them to self-destruct (undergo apoptosis). The CARD14 protein is found in many of the body's tissues, but it is particularly abundant in the skin. NF-B signaling appears to play an important role in regulating inflammation in the skin. Mutations in the CARD14 gene lead to overactivation of NF-B signaling, which triggers an abnormal inflammatory response. Researchers are working to determine how these changes lead to the specific features of familial pityriasis rubra pilaris.
familial pityriasis rubra pilaris
Is familial pityriasis rubra pilaris inherited ?
Familial pityriasis rubra pilaris usually has an autosomal dominant inheritance pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Affected individuals usually inherit the condition from one affected parent. However, the condition is said to have incomplete penetrance because not everyone who inherits the altered gene from a parent develops the condition's characteristic skin abnormalities. The other types of pityriasis rubra pilaris are sporadic, which means they occur in people with no history of the disorder in their family.
familial pityriasis rubra pilaris
What are the treatments for familial pityriasis rubra pilaris ?
These resources address the diagnosis or management of familial pityriasis rubra pilaris: - Genetic Testing Registry: Pityriasis rubra pilaris 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
familial pityriasis rubra pilaris
What is (are) hereditary paraganglioma-pheochromocytoma ?
Hereditary paraganglioma-pheochromocytoma is a condition characterized by the growth of noncancerous (benign) tumors in structures called paraganglia. Paraganglia are groups of cells that are found near nerve cell bunches called ganglia. A tumor involving the paraganglia is known as a paraganglioma. A type of paraganglioma known as a pheochromocytoma develops in the adrenal glands, which are located on top of each kidney and produce hormones in response to stress. Other types of paraganglioma are usually found in the head, neck, or trunk. People with hereditary paraganglioma-pheochromocytoma develop one or more paragangliomas, which may include pheochromocytomas. Pheochromocytomas and some other paragangliomas are associated with ganglia of the sympathetic nervous system. The sympathetic nervous system controls the "fight-or-flight" response, a series of changes in the body due to hormones released in response to stress. Sympathetic paragangliomas found outside the adrenal glands, usually in the abdomen, are called extra-adrenal paragangliomas. Most sympathetic paragangliomas, including pheochromocytomas, produce hormones called catecholamines, such as epinephrine (adrenaline) or norepinephrine. These excess catecholamines can cause signs and symptoms such as high blood pressure (hypertension), episodes of rapid heartbeat (palpitations), headaches, or sweating. Most paragangliomas are associated with ganglia of the parasympathetic nervous system, which controls involuntary body functions such as digestion and saliva formation. Parasympathetic paragangliomas, typically found in the head and neck, usually do not produce hormones. However, large tumors may cause signs and symptoms such as coughing, hearing loss in one ear, or difficulty swallowing. Although most paragangliomas and pheochromocytomas are noncancerous, some can become cancerous (malignant) and spread to other parts of the body (metastasize). Extra-adrenal paragangliomas become malignant more often than other types of paraganglioma or pheochromocytoma. Researchers have identified four types of hereditary paraganglioma-pheochromocytoma, named types 1 through 4. Each type is distinguished by its genetic cause. People with types 1, 2, and 3 typically develop paragangliomas in the head or neck region. People with type 4 usually develop extra-adrenal paragangliomas in the abdomen and are at higher risk for malignant tumors that metastasize. Hereditary paraganglioma-pheochromocytoma is typically diagnosed in a person's 30s.
hereditary paraganglioma-pheochromocytoma
How many people are affected by hereditary paraganglioma-pheochromocytoma ?
Hereditary paraganglioma-pheochromocytoma occurs in approximately 1 in 1 million people.
hereditary paraganglioma-pheochromocytoma
What are the genetic changes related to hereditary paraganglioma-pheochromocytoma ?
Mutations in at least four genes increase the risk of developing the different types of hereditary paraganglioma-pheochromocytoma. Mutations in the SDHD gene predispose an individual to hereditary paraganglioma-pheochromocytoma type 1; mutations in the SDHAF2 gene predispose to type 2; mutations in the SDHC gene predispose to type 3; and mutations in the SDHB gene predispose to type 4. The SDHB, SDHC, and SDHD genes provide instructions for making three of the four subunits of an enzyme called succinate dehydrogenase (SDH). In addition, the protein made by the SDHAF2 gene is required for the SDH enzyme to function. The SDH enzyme links two important cellular pathways called the citric acid cycle (or Krebs cycle) and oxidative phosphorylation. These pathways are critical in converting the energy from food into a form that cells can use. As part of the citric acid cycle, the SDH enzyme converts a compound called succinate to another compound called fumarate. Succinate acts as an oxygen sensor in the cell and can help turn on specific pathways that stimulate cells to grow in a low-oxygen environment (hypoxia). Mutations in the SDHB, SDHC, SDHD, and SDHAF2 genes lead to the loss or reduction of SDH enzyme activity. Because the mutated SDH enzyme cannot convert succinate to fumarate, succinate accumulates in the cell. As a result, the hypoxia pathways are triggered in normal oxygen conditions, which lead to abnormal cell growth and tumor formation.
hereditary paraganglioma-pheochromocytoma
Is hereditary paraganglioma-pheochromocytoma inherited ?
Hereditary paraganglioma-pheochromocytoma is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase the risk of developing tumors. An additional mutation that deletes the normal copy of the gene is needed to cause the condition. This second mutation, called a somatic mutation, is acquired during a person's lifetime and is present only in tumor cells. The risk of developing hereditary paraganglioma-pheochromocytoma types 1 and 2 is passed on only if the mutated copy of the gene is inherited from the father. The mechanism of this pattern of inheritance is unknown. The risk of developing types 3 and 4 can be inherited from the mother or the father.
hereditary paraganglioma-pheochromocytoma
What are the treatments for hereditary paraganglioma-pheochromocytoma ?
These resources address the diagnosis or management of hereditary paraganglioma-pheochromocytoma: - Gene Review: Gene Review: Hereditary Paraganglioma-Pheochromocytoma Syndromes - Genetic Testing Registry: Paragangliomas 1 - Genetic Testing Registry: Paragangliomas 2 - Genetic Testing Registry: Paragangliomas 3 - Genetic Testing Registry: Paragangliomas 4 - MedlinePlus Encyclopedia: Pheochromocytoma - National Cancer Institute: Pheochromocytoma and Paraganglioma 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
hereditary paraganglioma-pheochromocytoma
What is (are) glycine encephalopathy ?
Glycine encephalopathy, which is also known as nonketotic hyperglycinemia or NKH, is a genetic disorder characterized by abnormally high levels of a molecule called glycine. This molecule is an amino acid, which is a building block of proteins. Glycine also acts as a neurotransmitter, which is a chemical messenger that transmits signals in the brain. Glycine encephalopathy is caused by the shortage of an enzyme that normally breaks down glycine in the body. A lack of this enzyme allows excess glycine to build up in tissues and organs, particularly the brain, leading to serious medical problems. The most common form of glycine encephalopathy, called the classical type, appears shortly after birth. Affected infants experience a progressive lack of energy (lethargy), feeding difficulties, weak muscle tone (hypotonia), abnormal jerking movements, and life-threatening problems with breathing. Most children who survive these early signs and symptoms develop profound intellectual disability and seizures that are difficult to treat. For unknown reasons, affected males are more likely to survive and have less severe developmental problems than affected females. Researchers have identified several other types of glycine encephalopathy with variable signs and symptoms. The most common of these atypical types is called the infantile form. Children with this condition develop normally until they are about 6 months old, when they experience delayed development and may begin having seizures. As they get older, many develop intellectual disability, abnormal movements, and behavioral problems. Other atypical types of glycine encephalopathy appear later in childhood or adulthood and cause a variety of medical problems that primarily affect the nervous system. Rarely, the characteristic features of classical glycine encephalopathy improve with time. These cases are classified as transient glycine encephalopathy. In this form of the condition, glycine levels decrease to normal or near-normal after being very high at birth. Many children with temporarily high glycine levels go on to develop normally and experience few long-term medical problems. Intellectual disability and seizures occur in some affected individuals, however, even after glycine levels decrease.
glycine encephalopathy
How many people are affected by glycine encephalopathy ?
The worldwide incidence of glycine encephalopathy is unknown. Its frequency has been studied in only a few regions: this condition affects about 1 in 55,000 newborns in Finland and about 1 in 63,000 newborns in British Columbia, Canada.
glycine encephalopathy
What are the genetic changes related to glycine encephalopathy ?
Mutations in the AMT and GLDC genes cause glycine encephalopathy. About 80 percent of cases of glycine encephalopathy result from mutations in the GLDC gene, while AMT mutations cause 10 percent to 15 percent of all cases. In a small percentage of affected individuals, the cause of this condition is unknown. The AMT and GLDC genes provide instructions for making proteins that work together as part of a larger enzyme complex. This complex, known as glycine cleavage enzyme, is responsible for breaking down glycine into smaller pieces. Mutations in either the AMT or GLDC gene prevent the complex from breaking down glycine properly. When glycine cleavage enzyme is defective, excess glycine can build up to toxic levels in the body's organs and tissues. Damage caused by harmful amounts of this molecule in the brain and spinal cord is responsible for the intellectual disability, seizures, and breathing difficulties characteristic of glycine encephalopathy.
glycine encephalopathy
Is glycine encephalopathy 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.
glycine encephalopathy
What are the treatments for glycine encephalopathy ?
These resources address the diagnosis or management of glycine encephalopathy: - Baby's First Test - Gene Review: Gene Review: Glycine Encephalopathy - Genetic Testing Registry: Non-ketotic hyperglycinemia 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
glycine encephalopathy