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What is (are) Wagner syndrome ?
Wagner syndrome is a hereditary disorder that causes progressive vision loss. The eye problems that lead to vision loss typically begin in childhood, although the vision impairment might not be immediately apparent. In people with Wagner syndrome, the light-sensitive tissue that lines the back of the eye (the retina) becomes thin and may separate from the back of the eye (retinal detachment). The blood vessels within the retina (known as the choroid) may also be abnormal. The retina and the choroid progressively break down (degenerate). Some people with Wagner syndrome have blurred vision because of ectopic fovea, an abnormality in which the part of the retina responsible for sharp central vision is out of place. Additionally, the thick, clear gel that fills the eyeball (the vitreous) becomes watery and thin. People with Wagner syndrome develop a clouding of the lens of the eye (cataract). Affected individuals may also experience nearsightedness (myopia), progressive night blindness, or a narrowing of their field of vision. Vision impairment in people with Wagner syndrome can vary from near normal vision to complete loss of vision in both eyes.
Wagner syndrome
How many people are affected by Wagner syndrome ?
Wagner syndrome is a rare disorder, although its exact prevalence is unknown. Approximately 300 affected individuals have been described worldwide; about half of these individuals are from the Netherlands.
Wagner syndrome
What are the genetic changes related to Wagner syndrome ?
Mutations in the VCAN gene cause Wagner syndrome. The VCAN gene provides instructions for making a protein called versican. Versican is found in the extracellular matrix, which is the intricate lattice of proteins and other molecules that forms in the spaces between cells. Versican interacts with many of these proteins and molecules to facilitate the assembly of the extracellular matrix and ensure its stability. Within the eye, versican interacts with other proteins to maintain the structure and gel-like consistency of the vitreous. VCAN gene mutations that cause Wagner syndrome lead to insufficient levels of versican in the vitreous. Without enough versican to interact with the many proteins of the vitreous, the structure becomes unstable. This lack of stability in the vitreous affects other areas of the eye and contributes to the vision problems that occur in people with Wagner syndrome. It is unknown why VCAN gene mutations seem solely to affect vision.
Wagner syndrome
Is Wagner 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.
Wagner syndrome
What are the treatments for Wagner syndrome ?
These resources address the diagnosis or management of Wagner syndrome: - Gene Review: Gene Review: VCAN-Related Vitreoretinopathy - Genetic Testing Registry: Wagner 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
Wagner syndrome
What is (are) facioscapulohumeral muscular dystrophy ?
Facioscapulohumeral muscular dystrophy is a disorder characterized by muscle weakness and wasting (atrophy). This condition gets its name from the muscles that are affected most often: those of the face (facio-), around the shoulder blades (scapulo-), and in the upper arms (humeral). The signs and symptoms of facioscapulohumeral muscular dystrophy usually appear in adolescence. However, the onset and severity of the condition varies widely. Milder cases may not become noticeable until later in life, whereas rare severe cases become apparent in infancy or early childhood. Weakness involving the facial muscles or shoulders is usually the first symptom of this condition. Facial muscle weakness often makes it difficult to drink from a straw, whistle, or turn up the corners of the mouth when smiling. Weakness in muscles around the eyes can prevent the eyes from closing fully while a person is asleep, which can lead to dry eyes and other eye problems. For reasons that are unclear, weakness may be more severe in one side of the face than the other. Weak shoulder muscles tend to make the shoulder blades (scapulae) protrude from the back, a common sign known as scapular winging. Weakness in muscles of the shoulders and upper arms can make it difficult to raise the arms over the head or throw a ball. The muscle weakness associated with facioscapulohumeral muscular dystrophy worsens slowly over decades and may spread to other parts of the body. Weakness in muscles of the lower legs can lead to a condition called foot drop, which affects walking and increases the risk of falls. Muscular weakness in the hips and pelvis can make it difficult to climb stairs or walk long distances. Additionally, affected individuals may have an exaggerated curvature of the lower back (lordosis) due to weak abdominal muscles. About 20 percent of affected individuals eventually require the use of a wheelchair. Additional signs and symptoms of facioscapulohumeral muscular dystrophy can include mild high-tone hearing loss and abnormalities involving the light-sensitive tissue at the back of the eye (the retina). These signs are often not noticeable and may be discovered only during medical testing. Rarely, facioscapulohumeral muscular dystrophy affects the heart (cardiac) muscle or muscles needed for breathing. Researchers have described two types of facioscapulohumeral muscular dystrophy: type 1 (FSHD1) and type 2 (FSHD2). The two types have the same signs and symptoms and are distinguished by their genetic cause.
facioscapulohumeral muscular dystrophy
How many people are affected by facioscapulohumeral muscular dystrophy ?
Facioscapulohumeral muscular dystrophy has an estimated prevalence of 1 in 20,000 people. About 95 percent of all cases are FSHD1; the remaining 5 percent are FSHD2.
facioscapulohumeral muscular dystrophy
What are the genetic changes related to facioscapulohumeral muscular dystrophy ?
Facioscapulohumeral muscular dystrophy is caused by genetic changes involving the long (q) arm of chromosome 4. Both types of the disease result from changes in a region of DNA near the end of the chromosome known as D4Z4. This region consists of 11 to more than 100 repeated segments, each of which is about 3,300 DNA base pairs (3.3 kb) long. The entire D4Z4 region is normally hypermethylated, which means that it has a large number of methyl groups (consisting of one carbon atom and three hydrogen atoms) attached to the DNA. The addition of methyl groups turns off (silences) genes, so hypermethylated regions of DNA tend to have fewer genes that are turned on (active). Facioscapulohumeral muscular dystrophy results when the D4Z4 region is hypomethylated, with a shortage of attached methyl groups. In FSHD1, hypomethylation occurs because the D4Z4 region is abnormally shortened (contracted), containing between 1 and 10 repeats instead of the usual 11 to 100 repeats. In FSHD2, hypomethylation most often results from mutations in a gene called SMCHD1, which provides instructions for making a protein that normally hypermethylates the D4Z4 region. However, about 20 percent of people with FSHD2 do not have an identified mutation in the SMCHD1 gene, and the cause of the hypomethylation is unknown. Hypermethylation of the D4Z4 region normally keeps a gene called DUX4 silenced in most adult cells and tissues. The DUX4 gene is located in the segment of the D4Z4 region closest to the end of chromosome 4. In people with facioscapulohumeral muscular dystrophy, hypomethylation of the D4Z4 region prevents the DUX4 gene from being silenced in cells and tissues where it is usually turned off. Although little is known about the function of the DUX4 gene when it is active, researchers believe that it influences the activity of other genes, particularly in muscle cells. It is unknown how abnormal activity of the DUX4 gene damages or destroys these cells, leading to progressive muscle weakness and atrophy. The DUX4 gene is located next to a regulatory region of DNA on chromosome 4 known as a pLAM sequence, which is necessary for the production of the DUX4 protein. Some copies of chromosome 4 have a functional pLAM sequence, while others do not. Copies of chromosome 4 with a functional pLAM sequence are described as 4qA or "permissive." Those without a functional pLAM sequence are described as 4qB or "non-permissive." Without a functional pLAM sequence, no DUX4 protein is made. Because there are two copies of chromosome 4 in each cell, individuals may have two "permissive" copies of chromosome 4, two "non-permissive" copies, or one of each. Facioscapulohumeral muscular dystrophy can only occur in people who have at least one "permissive" copy of chromosome 4. Whether an affected individual has a contracted D4Z4 region or a SMCHD1 gene mutation, the disease results only if a functional pLAM sequence is also present to allow DUX4 protein to be produced. Studies suggest that mutations in the SMCHD1 gene, which cause FSHD2, can also increase the severity of the disease in people with FSHD1. Researchers suspect that the combination of a contracted D4Z4 region and a SMCHD1 gene mutation causes the D4Z4 region to have even fewer methyl groups attached, which allows the DUX4 gene to be highly active. In people with both genetic changes, the overactive gene leads to severe muscle weakness and atrophy.
facioscapulohumeral muscular dystrophy
Is facioscapulohumeral muscular dystrophy inherited ?
FSHD1 is inherited in an autosomal dominant pattern, which means one copy of the shortened D4Z4 region on a "permissive" chromosome 4 is sufficient to cause the disorder. In most cases, an affected person inherits the altered chromosome from one affected parent. Other people with FSHD1 have no history of the disorder in their family. These cases are described as sporadic and are caused by a new (de novo) D4Z4 contraction on one copy of a "permissive" chromosome 4. FSHD2 is inherited in a digenic pattern, which means that two independent genetic changes are necessary to cause the disorder. To have FSHD2, an individual must inherit a mutation in the SMCHD1 gene (which is located on chromosome 18) and, separately, they must inherit one copy of a "permissive" chromosome 4. Affected individuals typically inherit the SMCHD1 gene mutation from one parent and the "permissive" chromosome 4 from the other parent. (Because neither parent has both genetic changes in most cases, they are typically unaffected.)
facioscapulohumeral muscular dystrophy
What are the treatments for facioscapulohumeral muscular dystrophy ?
These resources address the diagnosis or management of facioscapulohumeral muscular dystrophy: - Gene Review: Gene Review: Facioscapulohumeral Muscular Dystrophy - Genetic Testing Registry: Facioscapulohumeral muscular dystrophy - Genetic Testing Registry: Facioscapulohumeral muscular dystrophy 2 - MedlinePlus Encyclopedia: Facioscapulohumeral Muscular 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
facioscapulohumeral muscular dystrophy
What is (are) Roberts syndrome ?
Roberts syndrome is a genetic disorder characterized by limb and facial abnormalities. Affected individuals also grow slowly before and after birth. Mild to severe intellectual impairment occurs in half of all people with Roberts syndrome. Children with Roberts syndrome are born with abnormalities of all four limbs. They have shortened arm and leg bones (hypomelia), particularly the bones in their forearms and lower legs. In severe cases, the limbs may be so short that the hands and feet are located very close to the body (phocomelia). People with Roberts syndrome may also have abnormal or missing fingers and toes, and joint deformities (contractures) commonly occur at the elbows and knees. The limb abnormalities are very similar on the right and left sides of the body, but arms are usually more severely affected than legs. Individuals with Roberts syndrome typically have numerous facial abnormalities, including an opening in the lip (a cleft lip) with or without an opening in the roof of the mouth (cleft palate), a small chin (micrognathia), ear abnormalities, wide-set eyes (hypertelorism), outer corners of the eyes that point downward (down-slanting palpebral fissures), small nostrils, and a beaked nose. They may have a small head size (microcephaly), and in severe cases affected individuals have a sac-like protrusion of the brain (encephalocele) at the front of their head. In addition, people with Roberts syndrome may have heart, kidney, and genital abnormalities. Infants with a severe form of Roberts syndrome are often stillborn or die shortly after birth. Mildly affected individuals may live into adulthood. A condition called SC phocomelia syndrome was originally thought to be distinct from Roberts syndrome; however, it is now considered to be a mild variant. "SC" represents the first letters of the surnames of the two families first diagnosed with this disorder.
Roberts syndrome
How many people are affected by Roberts syndrome ?
Roberts syndrome is a rare disorder; approximately 150 affected individuals have been reported.
Roberts syndrome
What are the genetic changes related to Roberts syndrome ?
Mutations in the ESCO2 gene cause Roberts syndrome. This gene provides instructions for making a protein that is important for proper chromosome separation during cell division. Before cells divide, they must copy all of their chromosomes. The copied DNA from each chromosome is arranged into two identical structures, called sister chromatids. The ESCO2 protein plays an important role in establishing the glue that holds the sister chromatids together until the chromosomes are ready to separate. All identified mutations in the ESCO2 gene prevent the cell from producing any functional ESCO2 protein, which causes some of the glue between sister chromatids to be missing around the chromosome's constriction point (centromere). In Roberts syndrome, cells respond to abnormal sister chromatid attachment by delaying cell division. Delayed cell division can be a signal that the cell should undergo self-destruction. The signs and symptoms of Roberts syndrome may result from the loss of cells from various tissues during early development. Because both mildly and severely affected individuals lack any functional ESCO2 protein, the underlying cause of the variation in disease severity remains unknown. Researchers suspect that other genetic and environmental factors may be involved.
Roberts syndrome
Is Roberts 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.
Roberts syndrome
What are the treatments for Roberts syndrome ?
These resources address the diagnosis or management of Roberts syndrome: - Gene Review: Gene Review: Roberts Syndrome - Genetic Testing Registry: Roberts-SC phocomelia syndrome - MedlinePlus Encyclopedia: Contracture deformity - MedlinePlus Encyclopedia: Microcephaly 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
Roberts syndrome
What is (are) cartilage-hair hypoplasia ?
Cartilage-hair hypoplasia is a disorder of bone growth characterized by short stature (dwarfism) with other skeletal abnormalities; fine, sparse hair (hypotrichosis); and abnormal immune system function (immune deficiency) that can lead to recurrent infections. People with cartilage-hair hypoplasia have unusually short limbs and short stature from birth. They typically have malformations in the cartilage near the ends of the long bones in the arms and legs (metaphyseal chondrodysplasia), which then affects development of the bone itself. Most people with cartilage-hair hypoplasia are unusually flexible in some joints, but they may have difficulty extending their elbows fully. Affected individuals have hair that is lighter in color than that of other family members because the core of each hair, which contains some of the pigment that contributes the hair's color, is missing. The missing core also makes each strand of hair thinner, causing the hair to have a sparse appearance overall. Unusually light-colored skin (hypopigmentation), malformed nails, and dental abnormalities may also be seen in this disorder. The extent of the immune deficiency in cartilage-hair hypoplasia varies from mild to severe. Affected individuals with the most severe immune problems are considered to have severe combined immunodeficiency (SCID). People with SCID lack virtually all immune protection from bacteria, viruses, and fungi and are prone to repeated and persistent infections that can be very serious or life-threatening. These infections are often caused by "opportunistic" organisms that ordinarily do not cause illness in people with a normal immune system. Most people with cartilage-hair hypoplasia, even those who have milder immune deficiency, experience infections of the respiratory system, ears, and sinuses. In particular, the chicken pox virus (varicella) often causes dangerous infections in people with this disorder. Autoimmune disorders, which occur when the immune system malfunctions and attacks the body's tissues and organs, occur in some people with cartilage-hair hypoplasia. Affected individuals are also at an increased risk of developing cancer, particularly certain skin cancers (basal cell carcinomas), cancer of blood-forming cells (leukemia), and cancer of immune system cells (lymphoma). Some people with cartilage-hair hypoplasia experience gastrointestinal problems. These problems may include an inability to properly absorb nutrients or intolerance of a protein called gluten found in wheat and other grains (celiac disease). Affected individuals may have Hirschsprung disease, an intestinal disorder that causes severe constipation, intestinal blockage, and enlargement of the colon. Narrowing of the anus (anal stenosis) or blockage of the esophagus (esophageal atresia) may also occur.
cartilage-hair hypoplasia
How many people are affected by cartilage-hair hypoplasia ?
Cartilage-hair hypoplasia occurs most often in the Old Order Amish population, where it affects about 1 in 1,300 newborns. In people of Finnish descent, its incidence is approximately 1 in 20,000. Outside of these populations, the condition is rare, and its specific incidence is not known. It has been reported in individuals of European and Japanese descent.
cartilage-hair hypoplasia
What are the genetic changes related to cartilage-hair hypoplasia ?
Cartilage-hair hypoplasia is caused by mutations in the RMRP gene. Unlike many genes, the RMRP gene does not contain instructions for making a protein. Instead, a molecule called a noncoding RNA, a chemical cousin of DNA, is produced from the RMRP gene. This RNA attaches (binds) to several proteins, forming an enzyme complex called mitochondrial RNA-processing endoribonuclease, or RNase MRP. The RNase MRP enzyme is thought to be involved in several important processes in the cell. For example, it likely helps copy (replicate) the DNA found in the energy-producing centers of cells (mitochondria). The RNase MRP enzyme probably also processes ribosomal RNA, which is required for assembling protein building blocks (amino acids) into functioning proteins. In addition, this enzyme helps control the cell cycle, which is the cell's way of replicating itself in an organized, step-by-step fashion. Mutations in the RMRP gene likely result in the production of a noncoding RNA that is unstable. This unstable molecule cannot bind to some of the proteins needed to make the RNase MRP enzyme complex. These changes are believed to affect the activity of the enzyme, which interferes with its important functions within cells. Disruption of the RNase MRP enzyme complex causes the signs and symptoms of cartilage-hair hypoplasia.
cartilage-hair hypoplasia
Is cartilage-hair hypoplasia 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.
cartilage-hair hypoplasia
What are the treatments for cartilage-hair hypoplasia ?
These resources address the diagnosis or management of cartilage-hair hypoplasia: - Gene Review: Gene Review: Cartilage-Hair Hypoplasia - Anauxetic Dysplasia Spectrum Disorders - Genetic Testing Registry: Metaphyseal chondrodysplasia, McKusick 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
cartilage-hair hypoplasia
What is (are) T-cell immunodeficiency, congenital alopecia, and nail dystrophy ?
T-cell immunodeficiency, congenital alopecia, and nail dystrophy is a type of severe combined immunodeficiency (SCID), which is a group of disorders characterized by an almost total lack of immune protection from foreign invaders such as bacteria and viruses. People with this form of SCID are missing functional immune cells called T cells, which normally recognize and attack foreign invaders to prevent infection. Without functional T cells, affected individuals develop repeated and persistent infections starting early in life. The infections result in slow growth and can be life-threatening; without effective treatment, most affected individuals live only into infancy or early childhood. T-cell immunodeficiency, congenital alopecia, and nail dystrophy also affects growth of the hair and nails. Congenital alopecia refers to an absence of hair that is apparent from birth. Affected individuals have no scalp hair, eyebrows, or eyelashes. Nail dystrophy is a general term that describes malformed fingernails and toenails; in this condition, the nails are often ridged, pitted, or abnormally curved. Researchers have described abnormalities of the brain and spinal cord (central nervous system) in at least two cases of this condition. However, it is not yet known whether central nervous system abnormalities are a common feature of T-cell immunodeficiency, congenital alopecia, and nail dystrophy.
T-cell immunodeficiency, congenital alopecia, and nail dystrophy
How many people are affected by T-cell immunodeficiency, congenital alopecia, and nail dystrophy ?
T-cell immunodeficiency, congenital alopecia, and nail dystrophy is a rare disorder. It has been diagnosed in only a few individuals, almost all of whom are members of a large extended family from a community in southern Italy.
T-cell immunodeficiency, congenital alopecia, and nail dystrophy
What are the genetic changes related to T-cell immunodeficiency, congenital alopecia, and nail dystrophy ?
T-cell immunodeficiency, congenital alopecia, and nail dystrophy results from mutations in the FOXN1 gene. This gene provides instructions for making a protein that is important for development of the skin, hair, nails, and immune system. Studies suggest that this protein helps guide the formation of hair follicles and the growth of fingernails and toenails. The FOXN1 protein also plays a critical role in the formation of the thymus, which is a gland located behind the breastbone where T cells mature and become functional. Researchers suspect that the FOXN1 protein is also involved in the development of the central nervous system, although its role is unclear. Mutations in the FOXN1 gene prevent cells from making any functional FOXN1 protein. Without this protein, hair and nails cannot grow normally. A lack of FOXN1 protein also prevents the formation of the thymus. When this gland is not present, the immune system cannot produce mature, functional T cells to fight infections. As a result, people with T-cell immunodeficiency, congenital alopecia, and nail dystrophy develop recurrent serious infections starting early in life.
T-cell immunodeficiency, congenital alopecia, and nail dystrophy
Is T-cell immunodeficiency, congenital alopecia, and nail 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. However, some people who carry one copy of a mutated FOXN1 gene have abnormal fingernails or toenails.
T-cell immunodeficiency, congenital alopecia, and nail dystrophy
What are the treatments for T-cell immunodeficiency, congenital alopecia, and nail dystrophy ?
These resources address the diagnosis or management of T-cell immunodeficiency, congenital alopecia, and nail dystrophy: - Be The Match: What is a Bone Marrow Transplant? - Genetic Testing Registry: T-cell immunodeficiency, congenital alopecia and nail dystrophy - MedlinePlus Encyclopedia: Bone Marrow Transplant 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
T-cell immunodeficiency, congenital alopecia, and nail dystrophy
What is (are) auriculo-condylar syndrome ?
Auriculo-condylar syndrome is a condition that affects facial development, particularly development of the ears and lower jaw (mandible). Most people with auriculo-condylar syndrome have malformed outer ears ("auriculo-" refers to the ears). A hallmark of this condition is an ear abnormality called a "question-mark ear," in which the ears have a distinctive question-mark shape caused by a split that separates the upper part of the ear from the earlobe. Other ear abnormalities that can occur in auriculo-condylar syndrome include cupped ears, ears with fewer folds and grooves than usual (described as "simple"), narrow ear canals, small skin tags in front of or behind the ears, and ears that are rotated backward. Some affected individuals also have hearing loss. Abnormalities of the mandible are another characteristic feature of auriculo-condylar syndrome. These abnormalities often include an unusually small chin (micrognathia) and malfunction of the temporomandibular joint (TMJ), which connects the lower jaw to the skull. Problems with the TMJ affect how the upper and lower jaws fit together and can make it difficult to open and close the mouth. The term "condylar" in the name of the condition refers to the mandibular condyle, which is the upper portion of the mandible that forms part of the TMJ. Other features of auriculo-condylar syndrome can include prominent cheeks, an unusually small mouth (microstomia), differences in the size and shape of facial structures between the right and left sides of the face (facial asymmetry), and an opening in the roof of the mouth (cleft palate). These features vary, even among affected members of the same family.
auriculo-condylar syndrome
How many people are affected by auriculo-condylar syndrome ?
Auriculo-condylar syndrome appears to be a rare disorder. More than two dozen affected individuals have been described in the medical literature.
auriculo-condylar syndrome
What are the genetic changes related to auriculo-condylar syndrome ?
Auriculo-condylar syndrome can be caused by mutations in either the GNAI3 or PLCB4 gene. These genes provide instructions for making proteins that are involved in chemical signaling within cells. They help transmit information from outside the cell to inside the cell, which instructs the cell to grow, divide, or take on specialized functions. Studies suggest that the proteins produced from the GNAI3 and PLCB4 genes contribute to the development of the first and second pharyngeal arches, which are structures in the embryo that ultimately develop into the jawbones, facial muscles, middle ear bones, ear canals, outer ears, and related tissues. Mutations in these genes alter the formation of the lower jaw: instead of developing normally, the lower jaw becomes shaped more like the smaller upper jaw (maxilla). This abnormal shape leads to micrognathia and problems with TMJ function. Researchers are working to determine how mutations in these genes lead to the other developmental abnormalities associated with auriculo-condylar syndrome. In some people with the characteristic features of auriculo-condylar syndrome, a mutation in the GNAI3 or PLCB4 gene has not been found. The cause of the condition is unknown in these individuals.
auriculo-condylar syndrome
Is auriculo-condylar syndrome inherited ?
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is typically 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. Some people who have one altered copy of the GNAI3 or PLCB4 gene have no features related to auriculo-condylar syndrome. (This situation is known as reduced penetrance.) It is unclear why some people with a mutated gene develop the condition and other people with a mutated gene do not.
auriculo-condylar syndrome
What are the treatments for auriculo-condylar syndrome ?
These resources address the diagnosis or management of auriculo-condylar syndrome: - Genetic Testing Registry: Auriculocondylar syndrome 1 - Genetic Testing Registry: Auriculocondylar syndrome 2 - MedlinePlus Encyclopedia: Cleft Lip and Palate - MedlinePlus Encyclopedia: Pinna Abnormalities and Low-Set Ears 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
auriculo-condylar syndrome
What is (are) isobutyryl-CoA dehydrogenase deficiency ?
Isobutyryl-CoA dehydrogenase (IBD) deficiency is a condition that disrupts the breakdown of certain proteins. Normally, proteins from food are broken down into parts called amino acids. Amino acids can be further processed to provide energy for growth and development. People with IBD deficiency have inadequate levels of an enzyme that helps break down a particular amino acid called valine. Most people with IBD deficiency are asymptomatic, which means they do not have any signs or symptoms of the condition. A few children with IBD deficiency have developed features such as a weakened and enlarged heart (dilated cardiomyopathy), weak muscle tone (hypotonia), and developmental delay. This condition may also cause low numbers of red blood cells (anemia) and very low blood levels of carnitine, which is a natural substance that helps convert certain foods into energy. The range of signs and symptoms associated with IBD deficiency remains unclear because very few affected individuals have been reported.
isobutyryl-CoA dehydrogenase deficiency
How many people are affected by isobutyryl-CoA dehydrogenase deficiency ?
IBD deficiency is a rare disorder; approximately 22 cases have been reported in the medical literature.
isobutyryl-CoA dehydrogenase deficiency
What are the genetic changes related to isobutyryl-CoA dehydrogenase deficiency ?
Mutations in the ACAD8 gene cause IBD deficiency. This gene provides instructions for making the IBD enzyme, which is involved in breaking down valine. ACAD8 gene mutations reduce or eliminate the activity of the IBD enzyme. As a result, valine is not broken down properly. Impaired processing of valine may lead to reduced energy production and the features of IBD deficiency.
isobutyryl-CoA dehydrogenase deficiency
Is isobutyryl-CoA dehydrogenase 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.
isobutyryl-CoA dehydrogenase deficiency
What are the treatments for isobutyryl-CoA dehydrogenase deficiency ?
These resources address the diagnosis or management of isobutyryl-CoA dehydrogenase deficiency: - Baby's First Test - Genetic Testing Registry: Deficiency of isobutyryl-CoA dehydrogenase - MedlinePlus Encyclopedia: Dilated Cardiomyopathy 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
isobutyryl-CoA dehydrogenase deficiency
What is (are) Allan-Herndon-Dudley syndrome ?
Allan-Herndon-Dudley syndrome is a rare disorder of brain development that causes moderate to severe intellectual disability and problems with movement. This condition, which occurs exclusively in males, disrupts development from before birth. Although affected males have impaired speech and a limited ability to communicate, they seem to enjoy interaction with other people. Most children with Allan-Herndon-Dudley syndrome have weak muscle tone (hypotonia) and underdevelopment of many muscles (muscle hypoplasia). As they get older, they usually develop joint deformities called contractures, which restrict the movement of certain joints. Abnormal muscle stiffness (spasticity), muscle weakness, and involuntary movements of the arms and legs also limit mobility. As a result, many people with Allan-Herndon-Dudley syndrome are unable to walk independently and become wheelchair-bound by adulthood.
Allan-Herndon-Dudley syndrome
How many people are affected by Allan-Herndon-Dudley syndrome ?
Allan-Herndon-Dudley syndrome appears to be a rare disorder. About 25 families with individuals affected by this condition have been reported worldwide.
Allan-Herndon-Dudley syndrome
What are the genetic changes related to Allan-Herndon-Dudley syndrome ?
Mutations in the SLC16A2 gene cause Allan-Herndon-Dudley syndrome. The SLC16A2 gene, also known as MCT8, provides instructions for making a protein that plays a critical role in the development of the nervous system. This protein transports a particular hormone into nerve cells in the developing brain. This hormone, called triiodothyronine or T3, is produced by a butterfly-shaped gland in the lower neck called the thyroid. T3 appears to be critical for the normal formation and growth of nerve cells, as well as the development of junctions between nerve cells (synapses) where cell-to-cell communication occurs. T3 and other forms of thyroid hormone also help regulate the development of other organs and control the rate of chemical reactions in the body (metabolism). Gene mutations alter the structure and function of the SLC16A2 protein. As a result, this protein is unable to transport T3 into nerve cells effectively. A lack of this critical hormone in certain parts of the brain disrupts normal brain development, resulting in intellectual disability and problems with movement. Because T3 is not taken up by nerve cells, excess amounts of this hormone continue to circulate in the bloodstream. Increased T3 levels in the blood may be toxic to some organs and contribute to the signs and symptoms of Allan-Herndon-Dudley syndrome.
Allan-Herndon-Dudley syndrome
Is Allan-Herndon-Dudley syndrome inherited ?
This condition is inherited in an X-linked recessive 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), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one altered copy of the gene in each cell is called a carrier. She can pass on the mutated gene, but usually does not experience signs and symptoms of the disorder. Carriers of SLC16A2 mutations have normal intelligence and do not experience problems with movement. Some carriers have been diagnosed with thyroid disease, a condition which is relatively common in the general population. It is unclear whether thyroid disease is related to SLC16A2 gene mutations in these cases.
Allan-Herndon-Dudley syndrome
What are the treatments for Allan-Herndon-Dudley syndrome ?
These resources address the diagnosis or management of Allan-Herndon-Dudley syndrome: - Gene Review: Gene Review: MCT8-Specific Thyroid Hormone Cell-Membrane Transporter Deficiency - Genetic Testing Registry: Allan-Herndon-Dudley syndrome - MedlinePlus Encyclopedia: Intellectual Disability - MedlinePlus Encyclopedia: T3 Test 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
Allan-Herndon-Dudley syndrome
What is (are) Manitoba oculotrichoanal syndrome ?
Manitoba oculotrichoanal syndrome is a condition involving several characteristic physical features, particularly affecting the eyes (oculo-), hair (tricho-), and anus (-anal). People with Manitoba oculotrichoanal syndrome have widely spaced eyes (hypertelorism). They may also have other eye abnormalities including small eyes (microphthalmia), a notched or partially absent upper eyelid (upper eyelid coloboma), eyelids that are attached to the front surface of the eye (corneopalpebral synechiae), or eyes that are completely covered by skin and usually malformed (cryptophthalmos). These abnormalities may affect one or both eyes. Individuals with Manitoba oculotrichoanal syndrome usually have abnormalities of the front hairline, such as hair growth extending from the temple to the eye on one or both sides of the face. One or both eyebrows may be completely or partially missing. Most people with this disorder also have a wide nose with a notched tip; in some cases this notch extends up from the tip so that the nose appears to be divided into two halves (bifid nose). About 20 percent of people with Manitoba oculotrichoanal syndrome have defects in the abdominal wall, such as a soft out-pouching around the belly-button (an umbilical hernia) or an opening in the wall of the abdomen (an omphalocele) that allows the abdominal organs to protrude through the navel. Another characteristic feature of Manitoba oculotrichoanal syndrome is a narrow anus (anal stenosis) or an anal opening farther forward than usual. Umbilical wall defects or anal malformations may require surgical correction. Some affected individuals also have malformations of the kidneys. The severity of the features of Manitoba oculotrichoanal syndrome may vary even within the same family. With appropriate treatment, affected individuals generally have normal growth and development, intelligence, and life expectancy.
Manitoba oculotrichoanal syndrome
How many people are affected by Manitoba oculotrichoanal syndrome ?
Manitoba oculotrichoanal syndrome is estimated to occur in 2 to 6 in 1,000 people in a small isolated Ojibway-Cree community in northern Manitoba, Canada. Although this region has the highest incidence of the condition, it has also been diagnosed in a few people from other parts of the world.
Manitoba oculotrichoanal syndrome
What are the genetic changes related to Manitoba oculotrichoanal syndrome ?
Manitoba oculotrichoanal syndrome is caused by mutations in the FREM1 gene. The FREM1 gene provides instructions for making a protein that is involved in the formation and organization of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. The FREM1 protein is one of a group of proteins, including proteins called FRAS1 and FREM2, that interact during embryonic development as components of basement membranes. Basement membranes help anchor layers of cells lining the surfaces and cavities of the body (epithelial cells) to other embryonic tissues, including those that give rise to connective tissues such as skin and cartilage. The FREM1 gene mutations that have been identified in people with Manitoba oculotrichoanal syndrome delete genetic material from the FREM1 gene or result in a premature stop signal that leads to an abnormally short FREM1 protein. These mutations most likely result in a nonfunctional protein. Absence of functional FREM1 protein interferes with its role in embryonic basement membrane development and may also affect the location, stability, or function of the FRAS1 and FREM2 proteins. The features of Manitoba oculotrichoanal syndrome may result from the failure of neighboring embryonic tissues to fuse properly due to impairment of the basement membranes' anchoring function.
Manitoba oculotrichoanal syndrome
Is Manitoba oculotrichoanal 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.
Manitoba oculotrichoanal syndrome
What are the treatments for Manitoba oculotrichoanal syndrome ?
These resources address the diagnosis or management of Manitoba oculotrichoanal syndrome: - Gene Review: Gene Review: Manitoba Oculotrichoanal Syndrome - Genetic Testing Registry: Marles Greenberg Persaud syndrome - MedlinePlus Encyclopedia: Omphalocele Repair 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
Manitoba oculotrichoanal syndrome
What is (are) juvenile Paget disease ?
Juvenile Paget disease is a disorder that affects bone growth. This disease causes bones to be abnormally large, misshapen, and easily broken (fractured). The signs of juvenile Paget disease appear in infancy or early childhood. As bones grow, they become progressively weaker and more deformed. These abnormalities usually become more severe during the adolescent growth spurt, when bones grow very quickly. Juvenile Paget disease affects the entire skeleton, resulting in widespread bone and joint pain. The bones of the skull tend to grow unusually large and thick, which can lead to hearing loss. The disease also affects bones of the spine (vertebrae). The deformed vertebrae can collapse, leading to abnormal curvature of the spine. Additionally, weight-bearing long bones in the legs tend to bow and fracture easily, which can interfere with standing and walking.
juvenile Paget disease
How many people are affected by juvenile Paget disease ?
Juvenile Paget disease is rare; about 50 affected individuals have been identified worldwide.
juvenile Paget disease
What are the genetic changes related to juvenile Paget disease ?
Juvenile Paget disease is caused by mutations in the TNFRSF11B gene. This gene provides instructions for making a protein that is involved in bone remodeling, a normal process in which old bone is broken down and new bone is created to replace it. Bones are constantly being remodeled, and the process is carefully controlled to ensure that bones stay strong and healthy. Mutations in the TNFRSF11B gene lead to a much faster rate of bone remodeling starting early in life. Bone tissue is broken down more quickly than usual, and when new bone tissue grows it is larger, weaker, and less organized than normal bone. This abnormally fast bone remodeling underlies the problems with bone growth characteristic of juvenile Paget disease.
juvenile Paget disease
Is juvenile Paget disease 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.
juvenile Paget disease
What are the treatments for juvenile Paget disease ?
These resources address the diagnosis or management of juvenile Paget disease: - Genetic Testing Registry: Hyperphosphatasemia with bone disease 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
juvenile Paget disease
What is (are) autosomal recessive primary microcephaly ?
Autosomal recessive primary microcephaly (often shortened to MCPH, which stands for "microcephaly primary hereditary") is a condition in which infants are born with a very small head and a small brain. The term "microcephaly" comes from the Greek words for "small head." Infants with MCPH have an unusually small head circumference compared to other infants of the same sex and age. Head circumference is the distance around the widest part of the head, measured by placing a measuring tape above the eyebrows and ears and around the back of the head. Affected infants' brain volume is also smaller than usual, although they usually do not have any major abnormalities in the structure of the brain. The head and brain grow throughout childhood and adolescence, but they continue to be much smaller than normal. MCPH causes intellectual disability, which is typically mild to moderate and does not become more severe with age. Most affected individuals have delayed speech and language skills. Motor skills, such as sitting, standing, and walking, may also be mildly delayed. People with MCPH usually have few or no other features associated with the condition. Some have a narrow, sloping forehead; mild seizures; problems with attention or behavior; or short stature compared to others in their family. The condition typically does not affect any other major organ systems or cause other health problems.
autosomal recessive primary microcephaly
How many people are affected by autosomal recessive primary microcephaly ?
The prevalence of all forms of microcephaly that are present from birth (primary microcephaly) ranges from 1 in 30,000 to 1 in 250,000 newborns worldwide. About 200 families with MCPH have been reported in the medical literature. This condition is more common in several specific populations, such as in northern Pakistan, where it affects an estimated 1 in 10,000 newborns.
autosomal recessive primary microcephaly
What are the genetic changes related to autosomal recessive primary microcephaly ?
MCPH can result from mutations in at least seven genes. Mutations in the ASPM gene are the most common cause of the disorder, accounting for about half of all cases. The genes associated with MCPH play important roles in early brain development, particularly in determining brain size. Studies suggest that the proteins produced from many of these genes help regulate cell division in the developing brain. Mutations in any of the genes associated with MCPH impair early brain development. As a result, affected infants have fewer nerve cells (neurons) than normal and are born with an unusually small brain. The reduced brain size underlies the small head size, intellectual disability, and developmental delays seen in many affected individuals.
autosomal recessive primary microcephaly
Is autosomal recessive primary microcephaly 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 primary microcephaly
What are the treatments for autosomal recessive primary microcephaly ?
These resources address the diagnosis or management of MCPH: - Gene Review: Gene Review: Primary Autosomal Recessive Microcephalies and Seckel Syndrome Spectrum Disorders - Genetic Testing Registry: Primary autosomal recessive microcephaly 1 - Genetic Testing Registry: Primary autosomal recessive microcephaly 2 - Genetic Testing Registry: Primary autosomal recessive microcephaly 3 - Genetic Testing Registry: Primary autosomal recessive microcephaly 4 - Genetic Testing Registry: Primary autosomal recessive microcephaly 5 - Genetic Testing Registry: Primary autosomal recessive microcephaly 6 - Genetic Testing Registry: Primary autosomal recessive microcephaly 7 - MedlinePlus Encyclopedia: Head Circumference 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 primary microcephaly
What is (are) multiple epiphyseal dysplasia ?
Multiple epiphyseal dysplasia is a disorder of cartilage and bone development primarily affecting the ends of the long bones in the arms and legs (epiphyses). There are two types of multiple epiphyseal dysplasia, which can be distinguished by their pattern of inheritance. Both the dominant and recessive types have relatively mild signs and symptoms, including joint pain that most commonly affects the hips and knees, early-onset arthritis, and a waddling walk. Although some people with multiple epiphyseal dysplasia have mild short stature as adults, most are of normal height. The majority of individuals are diagnosed during childhood; however, some mild cases may not be diagnosed until adulthood. Recessive multiple epiphyseal dysplasia is distinguished from the dominant type by malformations of the hands, feet, and knees and abnormal curvature of the spine (scoliosis). About 50 percent of individuals with recessive multiple epiphyseal dysplasia are born with at least one abnormal feature, including an inward- and upward-turning foot (clubfoot), an opening in the roof of the mouth (cleft palate), an unusual curving of the fingers or toes (clinodactyly), or ear swelling. An abnormality of the kneecap called a double-layered patella is also relatively common.
multiple epiphyseal dysplasia
How many people are affected by multiple epiphyseal dysplasia ?
The incidence of dominant multiple epiphyseal dysplasia is estimated to be at least 1 in 10,000 newborns. The incidence of recessive multiple epiphyseal dysplasia is unknown. Both forms of this disorder may actually be more common because some people with mild symptoms are never diagnosed.
multiple epiphyseal dysplasia
What are the genetic changes related to multiple epiphyseal dysplasia ?
Mutations in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene can cause dominant multiple epiphyseal dysplasia. These genes provide instructions for making proteins that are found in the spaces between cartilage-forming cells (chondrocytes). These proteins interact with each other and play an important role in cartilage and bone formation. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development. Most cartilage is later converted to bone, except for the cartilage that continues to cover and protect the ends of bones and is present in the nose and external ears. The majority of individuals with dominant multiple epiphyseal dysplasia have mutations in the COMP gene. About 10 percent of affected individuals have mutations in the MATN3 gene. Mutations in the COMP or MATN3 gene prevent the release of the proteins produced from these genes into the spaces between the chondrocytes. The absence of these proteins leads to the formation of abnormal cartilage, which can cause the skeletal problems characteristic of dominant multiple epiphyseal dysplasia. The COL9A1, COL9A2, and COL9A3 genes provide instructions for making a protein called type IX collagen. Collagens are a family of proteins that strengthen and support connective tissues, such as skin, bone, cartilage, tendons, and ligaments. Mutations in the COL9A1, COL9A2, or COL9A3 gene are found in less than five percent of individuals with dominant multiple epiphyseal dysplasia. It is not known how mutations in these genes cause the signs and symptoms of this disorder. Research suggests that mutations in these genes may cause type IX collagen to accumulate inside the cell or interact abnormally with other cartilage components. Some people with dominant multiple epiphyseal dysplasia do not have a mutation in the COMP, COL9A1, COL9A2, COL9A3, or MATN3 gene. In these cases, the cause of the condition is unknown. Mutations in the SLC26A2 gene cause recessive multiple epiphyseal dysplasia. This gene provides instructions for making a protein that is essential for the normal development of cartilage and for its conversion to bone. Mutations in the SLC26A2 gene alter the structure of developing cartilage, preventing bones from forming properly and resulting in the skeletal problems characteristic of recessive multiple epiphyseal dysplasia.
multiple epiphyseal dysplasia
Is multiple epiphyseal dysplasia inherited ?
Multiple epiphyseal dysplasia can have different inheritance patterns. This condition can be 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 may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. Multiple epiphyseal dysplasia can also be inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. 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.
multiple epiphyseal dysplasia
What are the treatments for multiple epiphyseal dysplasia ?
These resources address the diagnosis or management of multiple epiphyseal dysplasia: - Cedars-Sinai Medical Center - Gene Review: Gene Review: Multiple Epiphyseal Dysplasia, Dominant - Gene Review: Gene Review: Multiple Epiphyseal Dysplasia, Recessive - Genetic Testing Registry: Multiple epiphyseal dysplasia 1 - Genetic Testing Registry: Multiple epiphyseal dysplasia 2 - Genetic Testing Registry: Multiple epiphyseal dysplasia 3 - Genetic Testing Registry: Multiple epiphyseal dysplasia 4 - Genetic Testing Registry: Multiple epiphyseal dysplasia 5 - Genetic Testing Registry: Multiple epiphyseal dysplasia 6 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
multiple epiphyseal dysplasia
What is (are) congenital sucrase-isomaltase deficiency ?
Congenital sucrase-isomaltase deficiency is a disorder that affects a person's ability to digest certain sugars. People with this condition cannot break down the sugars sucrose and maltose. Sucrose (a sugar found in fruits, and also known as table sugar) and maltose (the sugar found in grains) are called disaccharides because they are made of two simple sugars. Disaccharides are broken down into simple sugars during digestion. Sucrose is broken down into glucose and another simple sugar called fructose, and maltose is broken down into two glucose molecules. People with congenital sucrase-isomaltase deficiency cannot break down the sugars sucrose and maltose, and other compounds made from these sugar molecules (carbohydrates). Congenital sucrase-isomaltase deficiency usually becomes apparent after an infant is weaned and starts to consume fruits, juices, and grains. After ingestion of sucrose or maltose, an affected child will typically experience stomach cramps, bloating, excess gas production, and diarrhea. These digestive problems can lead to failure to gain weight and grow at the expected rate (failure to thrive) and malnutrition. Most affected children are better able to tolerate sucrose and maltose as they get older.
congenital sucrase-isomaltase deficiency
How many people are affected by congenital sucrase-isomaltase deficiency ?
The prevalence of congenital sucrase-isomaltase deficiency is estimated to be 1 in 5,000 people of European descent. This condition is much more prevalent in the native populations of Greenland, Alaska, and Canada, where as many as 1 in 20 people may be affected.
congenital sucrase-isomaltase deficiency
What are the genetic changes related to congenital sucrase-isomaltase deficiency ?
Mutations in the SI gene cause congenital sucrase-isomaltase deficiency. The SI gene provides instructions for producing the enzyme sucrase-isomaltase. This enzyme is found in the small intestine and is responsible for breaking down sucrose and maltose into their simple sugar components. These simple sugars are then absorbed by the small intestine. Mutations that cause this condition alter the structure, disrupt the production, or impair the function of sucrase-isomaltase. These changes prevent the enzyme from breaking down sucrose and maltose, causing the intestinal discomfort seen in individuals with congenital sucrase-isomaltase deficiency.
congenital sucrase-isomaltase deficiency
Is congenital sucrase-isomaltase 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.
congenital sucrase-isomaltase deficiency
What are the treatments for congenital sucrase-isomaltase deficiency ?
These resources address the diagnosis or management of congenital sucrase-isomaltase deficiency: - Genetic Testing Registry: Sucrase-isomaltase deficiency - MedlinePlus Encyclopedia: Abdominal bloating - MedlinePlus Encyclopedia: Inborn errors of metabolism - MedlinePlus Encyclopedia: Malabsorption 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 sucrase-isomaltase deficiency
What is (are) X-linked adrenal hypoplasia congenita ?
X-linked adrenal hypoplasia congenita is a disorder that mainly affects males. It involves many hormone-producing (endocrine) tissues in the body, particularly a pair of small glands on top of each kidney called the adrenal glands. These glands produce a variety of hormones that regulate many essential functions in the body. One of the main signs of this disorder is adrenal insufficiency, which occurs when the adrenal glands do not produce enough hormones. Adrenal insufficiency typically begins in infancy or childhood and can cause vomiting, difficulty with feeding, dehydration, extremely low blood sugar (hypoglycemia), and shock. If untreated, these complications are often life-threatening. Affected males may also have a shortage of male sex hormones, which leads to underdeveloped reproductive tissues, undescended testicles (cryptorchidism), delayed puberty, and an inability to father children (infertility). Together, these characteristics are known as hypogonadotropic hypogonadism. The onset and severity of these signs and symptoms can vary, even among affected members of the same family.
X-linked adrenal hypoplasia congenita
How many people are affected by X-linked adrenal hypoplasia congenita ?
X-linked adrenal hypoplasia congenita is estimated to affect 1 in 12,500 newborns.
X-linked adrenal hypoplasia congenita
What are the genetic changes related to X-linked adrenal hypoplasia congenita ?
Mutations in the NR0B1 gene cause X-linked adrenal hypoplasia congenita. The NR0B1 gene provides instructions to make a protein called DAX1. This protein plays an important role in the development and function of several hormone-producing (endocrine) tissues including the adrenal glands, two hormone-secreting glands in the brain (the hypothalamus and pituitary), and the gonads (ovaries in females and testes in males). The hormones produced by these glands control many important body functions. Some NR0B1 mutations result in the production of an inactive version of the DAX1 protein, while other mutations delete the entire gene. The resulting shortage of DAX1 disrupts the normal development and function of hormone-producing tissues in the body. The signs and symptoms of adrenal insufficiency and hypogonadotropic hypogonadism occur when endocrine glands do not produce the right amounts of certain hormones.
X-linked adrenal hypoplasia congenita
Is X-linked adrenal hypoplasia congenita inherited ?
This condition is inherited in an X-linked recessive 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), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation must be present in both copies of the gene to cause the disorder. Males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In X-linked recessive inheritance, a female with one mutated copy of the gene in each cell is called a carrier. She can pass on the altered gene, but usually does not experience signs and symptoms of the disorder. In rare cases, however, females who carry a NR0B1 mutation may experience adrenal insufficiency or signs of hypogonadotropic hypogonadism such as underdeveloped reproductive tissues, delayed puberty, and an absence of menstruation.
X-linked adrenal hypoplasia congenita
What are the treatments for X-linked adrenal hypoplasia congenita ?
These resources address the diagnosis or management of X-linked adrenal hypoplasia congenita: - Gene Review: Gene Review: X-Linked Adrenal Hypoplasia Congenita - Genetic Testing Registry: Congenital adrenal hypoplasia, X-linked - MedlinePlus Encyclopedia: Adrenal Glands - MedlinePlus Encyclopedia: Hypogonadotropic Hypogonadism 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 adrenal hypoplasia congenita
What is (are) osteoglophonic dysplasia ?
Osteoglophonic dysplasia is a condition characterized by abnormal bone growth that leads to severe head and face (craniofacial) abnormalities, dwarfism, and other features. The term osteoglophonic refers to the bones (osteo-) having distinctive hollowed out (-glophonic) areas that appear as holes on x-ray images. Premature fusion of certain bones in the skull (craniosynostosis) typically occurs in osteoglophonic dysplasia. The craniosynostosis associated with this disorder may give the head a tall appearance, often referred to in the medical literature as a tower-shaped skull, or a relatively mild version of a deformity called a cloverleaf skull. Characteristic facial features in people with osteoglophonic dysplasia include a prominent forehead (frontal bossing), widely spaced eyes (hypertelorism), flattening of the bridge of the nose and of the middle of the face (midface hypoplasia), a large tongue (macroglossia), a protruding jaw (prognathism), and a short neck. People with this condition usually have no visible teeth because the teeth never emerge from the jaw (clinical anodontia). In addition, the gums are often overgrown (hypertrophic gingiva). Infants with osteoglophonic dysplasia often experience failure to thrive, which means they do not gain weight and grow at the expected rate. Affected individuals have short, bowed legs and arms and are short in stature. They also have flat feet and short, broad hands and fingers. The life expectancy of people with osteoglophonic dysplasia depends on the extent of their craniofacial abnormalities; those that obstruct the air passages and affect the mouth and teeth can lead to respiratory problems and cause difficulty with eating and drinking. Despite the skull abnormalities, intelligence is generally not affected in this disorder.
osteoglophonic dysplasia
How many people are affected by osteoglophonic dysplasia ?
Osteoglophonic dysplasia is a rare disorder; its prevalence is unknown. Only about 15 cases have been reported in the medical literature.
osteoglophonic dysplasia
What are the genetic changes related to osteoglophonic dysplasia ?
Osteoglophonic dysplasia is caused by mutations in the FGFR1 gene, which provides instructions for making a protein called fibroblast growth factor receptor 1. This protein is one of four fibroblast growth factor receptors, which are related proteins that bind (attach) to other proteins called fibroblast growth factors. The growth factors and their receptors are involved in important processes such as cell division, regulation of cell growth and maturation, formation of blood vessels, wound healing, and embryonic development. In particular, they play a major role in skeletal development. The FGFR1 protein spans the cell membrane, so that one end of the protein remains inside the cell and the other end projects from the outer surface of the cell. When a fibroblast growth factor binds to the part of the FGFR1 protein outside the cell, the receptor triggers a cascade of chemical reactions inside the cell that instruct the cell to undergo certain changes, such as maturing to take on specialized functions. The FGFR1 protein is thought to play an important role in the development of the nervous system. This protein may also help regulate the growth of long bones, such as the large bones in the arms and legs. FGFR1 gene mutations that cause osteoglophonic dysplasia change single building blocks (amino acids) in the FGFR1 protein. The altered FGFR1 protein appears to cause prolonged signaling, which promotes premature fusion of bones in the skull and disrupts the regulation of bone growth in the arms and legs.
osteoglophonic dysplasia
Is osteoglophonic dysplasia 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. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. However, some affected individuals inherit the mutation from an affected parent.
osteoglophonic dysplasia
What are the treatments for osteoglophonic dysplasia ?
These resources address the diagnosis or management of osteoglophonic dysplasia: - Genetic Testing Registry: Osteoglophonic dysplasia - Seattle Children's Hospital: Dwarfism and Bone Dysplasias 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
osteoglophonic dysplasia
What is (are) hypochondroplasia ?
Hypochondroplasia is a form of short-limbed dwarfism. This condition affects the conversion of cartilage into bone (a process called ossification), particularly in the long bones of the arms and legs. Hypochondroplasia is similar to another skeletal disorder called achondroplasia, but the features tend to be milder. All people with hypochondroplasia have short stature. The adult height for men with this condition ranges from 138 centimeters to 165 centimeters (4 feet, 6 inches to 5 feet, 5 inches). The height range for adult women is 128 centimeters to 151 centimeters (4 feet, 2 inches to 4 feet, 11 inches). People with hypochondroplasia have short arms and legs and broad, short hands and feet. Other characteristic features include a large head, limited range of motion at the elbows, a sway of the lower back (lordosis), and bowed legs. These signs are generally less pronounced than those seen with achondroplasia and may not be noticeable until early or middle childhood. Some studies have reported that a small percentage of people with hypochondroplasia have mild to moderate intellectual disability or learning problems, but other studies have produced conflicting results.
hypochondroplasia
How many people are affected by hypochondroplasia ?
The incidence of hypochondroplasia is unknown. Researchers believe that it may be about as common as achondroplasia, which occurs in 1 in 15,000 to 40,000 newborns. More than 200 people worldwide have been diagnosed with hypochondroplasia.
hypochondroplasia
What are the genetic changes related to hypochondroplasia ?
About 70 percent of all cases of hypochondroplasia are caused by mutations in the FGFR3 gene. This gene provides instructions for making a protein that is involved in the development and maintenance of bone and brain tissue. Although it remains unclear how FGFR3 mutations lead to the features of hypochondroplasia, researchers believe that these genetic changes cause the protein to be overly active. The overactive FGFR3 protein likely interferes with skeletal development and leads to the disturbances in bone growth that are characteristic of this disorder. In the absence of a mutation in the FGFR3 gene, the cause of hypochondroplasia is unknown. Researchers suspect that mutations in other genes are involved, although these genes have not been identified.
hypochondroplasia
Is hypochondroplasia inherited ?
Hypochondroplasia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most people with hypochondroplasia have average-size parents; these cases result from a new mutation in the FGFR3 gene. In the remaining cases, people with hypochondroplasia have inherited an altered FGFR3 gene from one or two affected parents. Individuals who inherit two altered copies of this gene typically have more severe problems with bone growth than those who inherit a single FGFR3 mutation.
hypochondroplasia
What are the treatments for hypochondroplasia ?
These resources address the diagnosis or management of hypochondroplasia: - Gene Review: Gene Review: Hypochondroplasia - Genetic Testing Registry: Hypochondroplasia - MedlinePlus Encyclopedia: Lordosis 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
hypochondroplasia
What is (are) Refsum disease ?
Refsum disease is an inherited condition that causes vision loss, absence of the sense of smell (anosmia), and a variety of other signs and symptoms. The vision loss associated with Refsum disease is caused by an eye disorder called retinitis pigmentosa. This disorder affects the retina, the light-sensitive layer at the back of the eye. Vision loss occurs as the light-sensing cells of the retina gradually deteriorate. The first sign of retinitis pigmentosa is usually a loss of night vision, which often becomes apparent in childhood. Over a period of years, the disease disrupts side (peripheral) vision and may eventually lead to blindness. Vision loss and anosmia are seen in almost everyone with Refsum disease, but other signs and symptoms vary. About one-third of affected individuals are born with bone abnormalities of the hands and feet. Features that appear later in life can include progressive muscle weakness and wasting; poor balance and coordination (ataxia); hearing loss; and dry, scaly skin (ichthyosis). Additionally, some people with Refsum disease develop an abnormal heart rhythm (arrhythmia) and related heart problems that can be life-threatening.
Refsum disease
How many people are affected by Refsum disease ?
The prevalence of Refsum disease is unknown, although the condition is thought to be uncommon.
Refsum disease
What are the genetic changes related to Refsum disease ?
More than 90 percent of all cases of Refsum disease result from mutations in the PHYH gene. The remaining cases are caused by mutations in a gene called PEX7. The signs and symptoms of Refsum disease result from the abnormal buildup of a type of fatty acid called phytanic acid. This substance is obtained from the diet, particularly from beef and dairy products. It is normally broken down through a process called alpha-oxidation, which occurs in cell structures called peroxisomes. These sac-like compartments contain enzymes that process many different substances, such as fatty acids and certain toxic compounds. Mutations in either the PHYH or PEX7 gene disrupt the usual functions of peroxisomes, including the breakdown of phytanic acid. As a result, this substance builds up in the body's tissues. The accumulation of phytanic acid is toxic to cells, although it is unclear how an excess of this substance affects vision and smell and causes the other specific features of Refsum disease.
Refsum disease
Is Refsum disease 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.
Refsum disease
What are the treatments for Refsum disease ?
These resources address the diagnosis or management of Refsum disease: - Gene Review: Gene Review: Refsum Disease - Gene Review: Gene Review: Retinitis Pigmentosa Overview - Genetic Testing Registry: Phytanic acid storage disease - MedlinePlus Encyclopedia: Retinitis Pigmentosa 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
Refsum disease
What is (are) Noonan syndrome ?
Noonan syndrome is a condition that affects many areas of the body. It is characterized by mildly unusual facial characteristics, short stature, heart defects, bleeding problems, skeletal malformations, and many other signs and symptoms. People with Noonan syndrome have distinctive facial features such as a deep groove in the area between the nose and mouth (philtrum), widely spaced eyes that are usually pale blue or blue-green in color, and low-set ears that are rotated backward. Affected individuals may have a high arch in the roof of the mouth (high-arched palate), poor alignment of the teeth, and a small lower jaw (micrognathia). Many children with Noonan syndrome have a short neck and both children and adults may have excess neck skin (also called webbing) and a low hairline at the back of the neck. Approximately 50 to 70 percent of individuals with Noonan syndrome have short stature. At birth, they are usually of normal length and weight, but growth slows over time. Abnormal levels of growth hormone may contribute to the slow growth. Individuals with Noonan syndrome often have either a sunken chest (pectus excavatum) or a protruding chest (pectus carinatum). Some affected people may also have an abnormal side-to-side curvature of the spine (scoliosis). Most people with Noonan syndrome have a heart defect. The most common heart defect is a narrowing of the valve that controls blood flow from the heart to the lungs (pulmonary valve stenosis). Some affected individuals have hypertrophic cardiomyopathy, which is a thickening of the heart muscle that forces the heart to work harder to pump blood. A variety of bleeding disorders have been associated with Noonan syndrome. Some people may have excessive bruising, nosebleeds, or prolonged bleeding following injury or surgery. Women with a bleeding disorder typically have excessive bleeding during menstruation (menorrhagia) or childbirth. Adolescent males with Noonan syndrome typically experience delayed puberty. Affected individuals go through puberty starting at age 13 or 14 and have a reduced pubertal growth spurt. Most males with Noonan syndrome have undescended testicles (cryptorchidism), which may be related to delayed puberty or to infertility (inability to father a child) later in life. Females with Noonan syndrome typically have normal puberty and fertility. Noonan syndrome can cause a variety of other signs and symptoms. Most children diagnosed with Noonan syndrome have normal intelligence, but a small percentage has special educational needs, and some have intellectual disability. Some affected individuals have vision or hearing problems. Infants with Noonan syndrome may be born with puffy hands and feet caused by a buildup of fluid (lymphedema), which can go away on its own. Affected infants may also have feeding problems, which typically get better by age 1 or 2. Older individuals can also develop lymphedema, usually in the ankles and lower legs.
Noonan syndrome
How many people are affected by Noonan syndrome ?
Noonan syndrome occurs in approximately 1 in 1,000 to 2,500 people.
Noonan syndrome
What are the genetic changes related to Noonan syndrome ?
Mutations in the PTPN11, SOS1, RAF1, KRAS, NRAS and BRAF genes cause Noonan syndrome. Most cases of Noonan syndrome result from mutations in one of three genes, PTPN11, SOS1, or RAF1. PTPN11 gene mutations account for approximately 50 percent of all cases of Noonan syndrome. SOS1 gene mutations account for 10 to 15 percent and RAF1 gene mutations account for 5 to 10 percent of Noonan syndrome cases. About 2 percent of people with Noonan syndrome have mutations in the KRAS gene and usually have a more severe or atypical form of the disorder. It is not known how many cases are caused by mutations in the BRAF or NRAS genes, but it is likely a very small proportion. The cause of Noonan syndrome in the remaining 20 percent of people with this disorder is unknown. The PTPN11, SOS1, RAF1, KRAS, NRAS and BRAF genes all provide instructions for making proteins that are important in signaling pathways needed for the proper formation of several types of tissue during development. These proteins also play roles in cell division, cell movement, and cell differentiation (the process by which cells mature to carry out specific functions). Mutations in any of the genes listed above cause the resulting protein to be continuously active, rather than switching on and off in response to cell signals. This constant activation disrupts the regulation of systems that control cell growth and division, leading to the characteristic features of Noonan syndrome.
Noonan syndrome
Is Noonan 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.
Noonan syndrome
What are the treatments for Noonan syndrome ?
These resources address the diagnosis or management of Noonan syndrome: - Gene Review: Gene Review: Noonan Syndrome - Genetic Testing Registry: Noonan syndrome - Genetic Testing Registry: Noonan syndrome 1 - Genetic Testing Registry: Noonan syndrome 2 - Genetic Testing Registry: Noonan syndrome 3 - Genetic Testing Registry: Noonan syndrome 4 - Genetic Testing Registry: Noonan syndrome 5 - Genetic Testing Registry: Noonan syndrome 6 - Genetic Testing Registry: Noonan syndrome 7 - MedlinePlus Encyclopedia: Noonan 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
Noonan syndrome
What is (are) Lujan syndrome ?
Lujan syndrome is a condition characterized by intellectual disability, behavioral problems, and certain physical features. It occurs almost exclusively in males. The intellectual disability associated with Lujan syndrome is usually mild to moderate. Behavioral problems can include hyperactivity, aggressiveness, extreme shyness, and excessive attention-seeking. Some affected individuals have features of autism or related developmental disorders affecting communication and social interaction. A few have been diagnosed with psychiatric problems such as delusions and hallucinations. Characteristic physical features of Lujan syndrome include a tall, thin body and an unusually large head (macrocephaly). Affected individuals also have a long, thin face with distinctive facial features such as a prominent top of the nose (high nasal root); a short space between the nose and the upper lip (philtrum); a narrow roof of the mouth (palate); crowded teeth; and a small chin (micrognathia). Almost all people with this condition have weak muscle tone (hypotonia). Additional signs and symptoms of Lujan syndrome can include abnormal speech, heart defects, and abnormalities of the genitourinary system. Many affected individuals have long fingers and toes with an unusually large range of joint movement (hyperextensibility). Seizures and abnormalities of the tissue that connects the left and right halves of the brain (corpus callosum) have also been reported in people with this condition.
Lujan syndrome
How many people are affected by Lujan syndrome ?
Lujan syndrome appears to be an uncommon condition, but its prevalence is unknown.
Lujan syndrome
What are the genetic changes related to Lujan syndrome ?
Lujan syndrome is caused by at least one mutation in the MED12 gene. This gene provides instructions for making a protein that helps regulate gene activity; it is involved in many aspects of early development. The MED12 gene mutation that causes Lujan syndrome changes a single protein building block (amino acid) in the MED12 protein. This genetic change alters the structure, and presumably the function, of the MED12 protein. However, it is unclear how the mutation affects development and leads to the cognitive and physical features of Lujan syndrome.
Lujan syndrome
Is Lujan syndrome inherited ?
This condition is inherited in an X-linked recessive pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. 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 X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Lujan syndrome
What are the treatments for Lujan syndrome ?
These resources address the diagnosis or management of Lujan syndrome: - Gene Review: Gene Review: MED12-Related Disorders - Genetic Testing Registry: X-linked mental retardation with marfanoid habitus 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
Lujan syndrome
What is (are) Amish lethal microcephaly ?
Amish lethal microcephaly is a disorder in which infants are born with a very small head and underdeveloped brain. Infants with Amish lethal microcephaly have a sloping forehead and an extremely small head size. They may also have an unusually small lower jaw and chin (micrognathia) and an enlarged liver (hepatomegaly). Affected infants may have seizures and difficulty maintaining their body temperature. Often they become very irritable starting in the second or third month of life. A compound called alpha-ketoglutaric acid can be detected in their urine (alpha-ketoglutaric aciduria), and during episodes of viral illness they tend to develop elevated levels of acid in the blood and tissues (metabolic acidosis). Infants with this disorder typically feed adequately but do not develop skills such as purposeful movement or the ability to track faces and sounds. Affected infants live only about six months.
Amish lethal microcephaly
How many people are affected by Amish lethal microcephaly ?
Amish lethal microcephaly occurs in approximately 1 in 500 newborns in the Old Order Amish population of Pennsylvania. It has not been found outside this population.
Amish lethal microcephaly
What are the genetic changes related to Amish lethal microcephaly ?
Mutations in the SLC25A19 gene cause Amish lethal microcephaly. The SLC25A19 gene provides instructions for producing a protein that is a member of the solute carrier (SLC) family of proteins. Proteins in the SLC family transport various compounds across the membranes surrounding the cell and its component parts. The protein produced from the SLC25A19 gene transports a molecule called thiamine pyrophosphate into the mitochondria, the energy-producing centers of cells. This compound is involved in the activity of a group of mitochondrial enzymes called the dehydrogenase complexes, one of which is the alpha-ketoglutarate dehydrogenase complex. The transport of thiamine pyrophosphate into the mitochondria is believed to be important in brain development. All known individuals with Amish lethal microcephaly have a mutation in which the protein building block (amino acid) alanine is substituted for the amino acid glycine at position 177 of the SLC25A19 protein, written as Gly177Ala or G177A. Researchers believe that this mutation interferes with the transport of thiamine pyrophosphate into the mitochondria and the activity of the alpha-ketoglutarate dehydrogenase complex, resulting in the abnormal brain development and alpha-ketoglutaric aciduria seen in Amish lethal microcephaly.
Amish lethal microcephaly
Is Amish lethal microcephaly 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.
Amish lethal microcephaly
What are the treatments for Amish lethal microcephaly ?
These resources address the diagnosis or management of Amish lethal microcephaly: - Gene Review: Gene Review: Amish Lethal Microcephaly - Genetic Testing Registry: Amish lethal microcephaly - MedlinePlus Encyclopedia: Microcephaly 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
Amish lethal microcephaly