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201 | What is (are) Greenberg dysplasia ? | Greenberg dysplasia is a severe condition characterized by specific bone abnormalities in the developing fetus. This condition is fatal before birth. The bones of affected individuals do not develop properly, causing a distinctive spotted appearance called moth-eaten bone, which is visible on x-ray images. In addition, the bones have abnormal calcium deposits (ectopic calcification). Affected individuals have extremely short bones in the arms and legs and abnormally flat vertebrae (platyspondyly). Other skeletal abnormalities may include short ribs and extra fingers (polydactyly). In addition, affected fetuses have extensive swelling of the body caused by fluid accumulation (hydrops fetalis). Greenberg dysplasia is also called hydrops-ectopic calcification-moth-eaten skeletal dysplasia (HEM), which reflects the condition's most common features. | growth_hormone_receptor | a severe condition characterized by specific bone abnormalities in the developing fetus |
202 | How many people are affected by Greenberg dysplasia ? | Greenberg dysplasia is a very rare condition. Approximately ten cases have been reported in the scientific literature. | growth_hormone_receptor | ten |
203 | What are the genetic changes related to Greenberg dysplasia ? | Mutations in the LBR gene cause Greenberg dysplasia. This gene provides instructions for making a protein called the lamin B receptor. One region of this protein, called the sterol reductase domain, plays an important role in the production (synthesis) of cholesterol. Cholesterol is a type of fat that is produced in the body and obtained from foods that come from animals: eggs, meat, fish, and dairy products. Cholesterol is necessary for normal embryonic development and has important functions both before and after birth. Cholesterol is an important component of cell membranes and the protective substance covering nerve cells (myelin). Additionally, cholesterol plays a role in the production of certain hormones and digestive acids. During cholesterol synthesis, the sterol reductase function of the lamin B receptor allows the protein to perform one of several steps that convert a molecule called lanosterol to cholesterol. LBR gene mutations involved in Greenberg dysplasia lead to loss of the sterol reductase function of the lamin B receptor, and research suggests that this loss causes the condition. Absence of the sterol reductase function disrupts the normal synthesis of cholesterol within cells. This absence may also allow potentially toxic byproducts of cholesterol synthesis to build up in the body's tissues. Researchers suspect that low cholesterol levels or an accumulation of other substances disrupts the growth and development of many parts of the body. It is not known, however, how a disturbance of cholesterol synthesis leads to the specific features of Greenberg dysplasia. | growth_hormone_receptor | loss of the sterol reductase function |
204 | Is Greenberg dysplasia 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
205 | What are the treatments for Greenberg dysplasia ? | These resources address the diagnosis or management of Greenberg dysplasia: - Genetic Testing Registry: Greenberg dysplasia - Lurie Children's Hospital of Chicago: Fetal Skeletal Dysplasia 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 | growth_hormone_receptor | Fetal Skeletal Dysplasia |
206 | What is (are) X-linked infantile nystagmus ? | X-linked infantile nystagmus is a condition characterized by abnormal eye movements. Nystagmus is a term that refers to involuntary side-to-side movements of the eyes. In people with this condition, nystagmus is present at birth or develops within the first six months of life. The abnormal eye movements may worsen when an affected person is feeling anxious or tries to stare directly at an object. The severity of nystagmus varies, even among affected individuals within the same family. Sometimes, affected individuals will turn or tilt their head to compensate for the irregular eye movements. | growth_hormone_receptor | a condition characterized by abnormal eye movements |
207 | How many people are affected by X-linked infantile nystagmus ? | The incidence of all forms of infantile nystagmus is estimated to be 1 in 5,000 newborns; however, the precise incidence of X-linked infantile nystagmus is unknown. | growth_hormone_receptor | 1 in 5,000 |
208 | What are the genetic changes related to X-linked infantile nystagmus ? | Mutations in the FRMD7 gene cause X-linked infantile nystagmus. The FRMD7 gene provides instructions for making a protein whose exact function is unknown. This protein is found mostly in areas of the brain that control eye movement and in the light-sensitive tissue at the back of the eye (retina). Research suggests that FRMD7 gene mutations cause nystagmus by disrupting the development of certain nerve cells in the brain and retina. In some people with X-linked infantile nystagmus, no mutation in the FRMD7 gene has been found. The genetic cause of the disorder is unknown in these individuals. Researchers believe that mutations in at least one other gene, which has not been identified, can cause this disorder. | growth_hormone_receptor | no mutation in the FRMD7 gene has been found |
209 | Is X-linked infantile nystagmus 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 cause the condition, although affected females may experience less severe symptoms than affected males. Approximately half of the females with only one altered copy of the FRMD7 gene in each cell have no symptoms of this condition. | growth_hormone_receptor | This condition is inherited in an X-linked pattern |
210 | What are the treatments for X-linked infantile nystagmus ? | These resources address the diagnosis or management of X-linked infantile nystagmus: - Gene Review: Gene Review: FRMD7-Related Infantile Nystagmus - Genetic Testing Registry: Infantile nystagmus, X-linked - MedlinePlus Encyclopedia: Nystagmus 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 | growth_hormone_receptor | Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
211 | What is (are) 21-hydroxylase deficiency ? | 21-hydroxylase deficiency is an inherited disorder that affects the adrenal glands. The adrenal glands are located on top of the kidneys and produce a variety of hormones that regulate many essential functions in the body. In people with 21-hydroxylase deficiency, the adrenal glands produce excess androgens, which are male sex hormones. There are three types of 21-hydroxylase deficiency. Two types are classic forms, known as the salt-wasting and simple virilizing types. The third type is called the non-classic type. The salt-wasting type is the most severe, the simple virilizing type is less severe, and the non-classic type is the least severe form. Males and females with either classic form of 21-hydroxylase deficiency tend to have an early growth spurt, but their final adult height is usually shorter than others in their family. Additionally, affected individuals may have a reduced ability to have biological children (decreased fertility). Females may also develop excessive body hair growth (hirsutism), male pattern baldness, and irregular menstruation. Approximately 75 percent of individuals with classic 21-hydroxylase deficiency have the salt-wasting type. Hormone production is extremely low in this form of the disorder. Affected individuals lose large amounts of sodium in their urine, which can be life-threatening in early infancy. Babies with the salt-wasting type can experience poor feeding, weight loss, dehydration, and vomiting. Individuals with the simple virilizing form do not experience salt loss. In both the salt-wasting and simple virilizing forms of this disorder, females typically have external genitalia that do not look clearly male or female (ambiguous genitalia). Males usually have normal genitalia, but the testes may be small. Females with the non-classic type of 21-hydroxylase deficiency have normal female genitalia. As affected females get older, they may experience hirsutism, male pattern baldness, irregular menstruation, and decreased fertility. Males with the non-classic type may have early beard growth and small testes. Some individuals with this type of 21-hydroxylase deficiency have no symptoms of the disorder. | growth_hormone_receptor | an inherited disorder that affects the adrenal glands |
212 | How many people are affected by 21-hydroxylase deficiency ? | The classic forms of 21-hydroxylase deficiency occur in 1 in 15,000 newborns. The prevalence of the non-classic form of 21-hydroxylase deficiency is estimated to be 1 in 1,000 individuals. The prevalence of both classic and non-classic forms varies among different ethnic populations. 21-hydroxylase deficiency is one of a group of disorders known as congenital adrenal hyperplasias that impair hormone production and disrupt sexual development. 21-hydroxylase deficiency is responsible for about 95 percent of all cases of congenital adrenal hyperplasia. | growth_hormone_receptor | 1 in 1,000 |
213 | What are the genetic changes related to 21-hydroxylase deficiency ? | Mutations in the CYP21A2 gene cause 21-hydroxylase deficiency. The CYP21A2 gene provides instructions for making an enzyme called 21-hydroxylase. This enzyme is found in the adrenal glands, where it plays a role in producing hormones called cortisol and aldosterone. Cortisol has numerous functions, such as maintaining blood sugar levels, protecting the body from stress, and suppressing inflammation. Aldosterone is sometimes called the salt-retaining hormone because it regulates the amount of salt retained by the kidneys. The retention of salt affects fluid levels in the body and blood pressure. 21-hydroxylase deficiency is caused by a shortage (deficiency) of the 21-hydroxylase enzyme. When 21-hydroxylase is lacking, substances that are usually used to form cortisol and aldosterone instead build up in the adrenal glands and are converted to androgens. The excess production of androgens leads to abnormalities of sexual development in people with 21-hydroxylase deficiency. A lack of aldosterone production contributes to the salt loss in people with the salt-wasting form of this condition. The amount of functional 21-hydroxylase enzyme determines the severity of the disorder. Individuals with the salt-wasting type have CYP21A2 mutations that result in a completely nonfunctional enzyme. People with the simple virilizing type of this condition have CYP21A2 gene mutations that allow the production of low levels of functional enzyme. Individuals with the non-classic type of this disorder have CYP21A2 mutations that result in the production of reduced amounts of the enzyme, but more enzyme than either of the other types. | growth_hormone_receptor | a shortage |
214 | Is 21-hydroxylase 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
215 | What are the treatments for 21-hydroxylase deficiency ? | These resources address the diagnosis or management of 21-hydroxylase deficiency: - Baby's First Test - CARES Foundation: Treatment - Gene Review: Gene Review: 21-Hydroxylase-Deficient Congenital Adrenal Hyperplasia - Genetic Testing Registry: 21-hydroxylase deficiency - MedlinePlus Encyclopedia: Congenital Adrenal Hyperplasia 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 | growth_hormone_receptor | - Baby's First Test - CARES Foundation |
216 | What is (are) 48,XXYY syndrome ? | 48,XXYY syndrome is a chromosomal condition that causes medical and behavioral problems in males. 48,XXYY disrupts male sexual development. Adolescent and adult males with this condition typically have small testes that do not produce enough testosterone, which is the hormone that directs male sexual development. A shortage of testosterone during puberty can lead to reduced facial and body hair, poor muscle development, low energy levels, and an increased risk for breast enlargement (gynecomastia). Because their testes do not function normally, males with 48, XXYY syndrome have an inability to father children (infertility). 48,XXYY syndrome can affect other parts of the body as well. Males with 48,XXYY syndrome are often taller than other males their age. They tend to develop a tremor that typically starts in adolescence and worsens with age. Dental problems are frequently seen with this condition; they include delayed appearance of the primary (baby) or secondary (adult) teeth, thin tooth enamel, crowded and/or misaligned teeth, and multiple cavities. As affected males get older, they may develop a narrowing of the blood vessels in the legs, called peripheral vascular disease. Peripheral vascular disease can cause skin ulcers to form. Affected males are also at risk for developing a type of clot called a deep vein thrombosis (DVT) that occurs in the deep veins of the legs. Additionally, males with 48,XXYY syndrome may have flat feet (pes planus), elbow abnormalities, allergies, asthma, type 2 diabetes, seizures, and congenital heart defects. Most males with 48,XXYY syndrome have some degree of difficulty with speech and language development. Learning disabilities, especially reading problems, are very common in males with this disorder. Affected males seem to perform better at tasks focused on math, visual-spatial skills such as puzzles, and memorization of locations or directions. Some boys with 48,XXYY syndrome have delayed development of motor skills such as sitting, standing, and walking that can lead to poor coordination. Affected males have higher than average rates of behavioral disorders, such as attention deficit hyperactivity disorder (ADHD); mood disorders, including anxiety and bipolar disorder; and/or autism spectrum disorders, which affect communication and social interaction. | growth_hormone_receptor | a chromosomal condition |
217 | How many people are affected by 48,XXYY syndrome ? | 48,XXYY syndrome is estimated to affect 1 in 18,000 to 50,000 males. | growth_hormone_receptor | 1 in 18,000 to 50,000 |
218 | What are the genetic changes related to 48,XXYY syndrome ? | 48,XXYY syndrome is a condition related to the X and Y chromosomes (the sex chromosomes). People normally have 46 chromosomes in each cell. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help determine whether a person will develop male or female sex characteristics. Females typically have two X chromosomes (46,XX), and males have one X chromosome and one Y chromosome (46,XY). 48,XXYY syndrome results from the presence of an extra copy of both sex chromosomes in each of a male's cells (48,XXYY). Extra copies of genes on the X chromosome interfere with male sexual development, preventing the testes from functioning normally and reducing the levels of testosterone. Many genes are found only on the X or Y chromosome, but genes in areas known as the pseudoautosomal regions are present on both sex chromosomes. Extra copies of genes from the pseudoautosomal regions of the extra X and Y chromosome contribute to the signs and symptoms of 48,XXYY syndrome; however, the specific genes have not been identified. | growth_hormone_receptor | X and Y chromosomes |
219 | Is 48,XXYY syndrome inherited ? | This condition is not inherited; it usually occurs as a random event during the formation of reproductive cells (eggs and sperm). An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. In 48,XXYY syndrome, the extra sex chromosomes almost always come from a sperm cell. Nondisjunction may cause a sperm cell to gain two extra sex chromosomes, resulting in a sperm cell with three sex chromosomes (one X and two Y chromosomes). If that sperm cell fertilizes a normal egg cell with one X chromosome, the resulting child will have two X chromosomes and two Y chromosomes in each of the body's cells. In a small percentage of cases, 48,XXYY syndrome results from nondisjunction of the sex chromosomes in a 46,XY embryo very soon after fertilization has occurred. This means that an normal sperm cell with one Y chromosome fertilized a normal egg cell with one X chromosome, but right after fertilization nondisjunction of the sex chromosomes caused the embryo to gain two extra sex chromosomes, resulting in a 48,XXYY embryo. | growth_hormone_receptor | This condition is not inherited |
220 | What are the treatments for 48,XXYY syndrome ? | These resources address the diagnosis or management of 48,XXYY syndrome: - Genetic Testing Registry: XXYY 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 | growth_hormone_receptor | Genetic Testing Registry |
221 | What is (are) frontometaphyseal dysplasia ? | Frontometaphyseal dysplasia is a disorder involving abnormalities in skeletal development and other health problems. It is a member of a group of related conditions called otopalatodigital spectrum disorders, which also includes otopalatodigital syndrome type 1, otopalatodigital syndrome type 2, and Melnick-Needles syndrome. In general, these disorders involve hearing loss caused by malformations in the tiny bones in the ears (ossicles), problems in the development of the roof of the mouth (palate), and skeletal abnormalities involving the fingers and/or toes (digits). Frontometaphyseal dysplasia is distinguished from the other otopalatodigital spectrum disorders by the presence of joint deformities called contractures that restrict the movement of certain joints. People with frontometaphyseal dysplasia may also have bowed limbs, an abnormal curvature of the spine (scoliosis), and abnormalities of the fingers and hands. Characteristic facial features may include prominent brow ridges; wide-set and downward-slanting eyes; a very small lower jaw and chin (micrognathia); and small, missing or misaligned teeth. Some affected individuals have hearing loss. In addition to skeletal abnormalities, individuals with frontometaphyseal dysplasia may have obstruction of the ducts between the kidneys and bladder (ureters), heart defects, or constrictions in the passages leading from the windpipe to the lungs (the bronchi) that can cause problems with breathing. Males with frontometaphyseal dysplasia generally have more severe signs and symptoms of the disorder than do females, who may show only the characteristic facial features. | growth_hormone_receptor | a disorder involving abnormalities in skeletal development and other health problems |
222 | How many people are affected by frontometaphyseal dysplasia ? | Frontometaphyseal dysplasia is a rare disorder; only a few dozen cases have been reported worldwide. | growth_hormone_receptor | a few dozen |
223 | What are the genetic changes related to frontometaphyseal dysplasia ? | Mutations in the FLNA gene cause frontometaphyseal dysplasia. The FLNA gene provides instructions for producing the protein filamin A, which helps build the network of protein filaments (cytoskeleton) that gives structure to cells and allows them to change shape and move. Filamin A binds to another protein called actin, and helps the actin to form the branching network of filaments that make up the cytoskeleton. Filamin A also links actin to many other proteins to perform various functions within the cell. A small number of mutations in the FLNA gene have been identified in people with frontometaphyseal dysplasia. These mutations are described as "gain-of-function" because they appear to enhance the activity of the filamin A protein or give the protein a new, atypical function. Researchers believe that the mutations may change the way the filamin A protein helps regulate processes involved in skeletal development, but it is not known how changes in the protein relate to the specific signs and symptoms of frontometaphyseal dysplasia. | growth_hormone_receptor | specific signs and symptoms |
224 | Is frontometaphyseal dysplasia inherited ? | This condition is inherited in an X-linked dominant pattern. The gene associated with this condition is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell is sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes the disorder. In most cases, males experience more severe symptoms of the disorder than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. | growth_hormone_receptor | This condition is inherited in an X-linked dominant pattern |
225 | What are the treatments for frontometaphyseal dysplasia ? | These resources address the diagnosis or management of frontometaphyseal dysplasia: - Gene Review: Gene Review: Otopalatodigital Spectrum Disorders - Genetic Testing Registry: Frontometaphyseal dysplasia 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 | growth_hormone_receptor | Diagnostic Tests |
226 | What is (are) Lowe syndrome ? | Lowe syndrome is a condition that primarily affects the eyes, brain, and kidneys. This disorder occurs almost exclusively in males. Infants with Lowe syndrome are born with thick clouding of the lenses in both eyes (congenital cataracts), often with other eye abnormalities that can impair vision. About half of affected infants develop an eye disease called infantile glaucoma, which is characterized by increased pressure within the eyes. Many individuals with Lowe syndrome have delayed development, and intellectual ability ranges from normal to severely impaired. Behavioral problems and seizures have also been reported in children with this condition. Most affected children have weak muscle tone from birth (neonatal hypotonia), which can contribute to feeding difficulties, problems with breathing, and delayed development of motor skills such as sitting, standing, and walking. Kidney (renal) abnormalities, most commonly a condition known as renal Fanconi syndrome, frequently develop in individuals with Lowe syndrome. The kidneys play an essential role in maintaining the right amounts of minerals, salts, water, and other substances in the body. In individuals with renal Fanconi syndrome, the kidneys are unable to reabsorb important nutrients into the bloodstream. Instead, the nutrients are excreted in the urine. These kidney problems lead to increased urination, dehydration, and abnormally acidic blood (metabolic acidosis). A loss of salts and nutrients may also impair growth and result in soft, bowed bones (hypophosphatemic rickets), especially in the legs. Progressive kidney problems in older children and adults with Lowe syndrome can lead to life-threatening renal failure and end-stage renal disease (ESRD). | growth_hormone_receptor | a condition that primarily affects the eyes, brain, and kidneys |
227 | How many people are affected by Lowe syndrome ? | Lowe syndrome is an uncommon condition. It has an estimated prevalence of 1 in 500,000 people. | growth_hormone_receptor | 1 in 500,000 |
228 | What are the genetic changes related to Lowe syndrome ? | Mutations in the OCRL gene cause Lowe syndrome. The OCRL gene provides instructions for making an enzyme that helps modify fat (lipid) molecules called membrane phospholipids. By controlling the levels of specific membrane phospholipids, the OCRL enzyme helps regulate the transport of certain substances to and from the cell membrane. This enzyme is also involved in the regulation of the actin cytoskeleton, which is a network of fibers that make up the cell's structural framework. The actin cytoskeleton has several critical functions, including determining cell shape and allowing cells to move. Some mutations in the OCRL gene prevent the production of any OCRL enzyme. Other mutations reduce or eliminate the activity of the enzyme or prevent it from interacting with other proteins within the cell. Researchers are working to determine how OCRL mutations cause the characteristic features of Lowe syndrome. Because the OCRL enzyme is present throughout the body, it is unclear why the medical problems associated with this condition are mostly limited to the brain, kidneys, and eyes. It is possible that other enzymes may be able to compensate for the defective OCRL enzyme in unaffected tissues. | growth_hormone_receptor | OCRL mutations |
229 | Is Lowe syndrome inherited ? | This condition is inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome), 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. Most X-linked disorders affect males much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. In some cases of Lowe syndrome, an affected male inherits the mutation from a mother who carries one altered copy of the OCRL gene. Other cases result from new mutations in the gene and occur in males with no history of the disorder in their family. Females who carry one mutated copy of the OCRL gene do not have the characteristic features of Lowe syndrome. Most female carriers, however, have changes in the lens of the eye that can be observed with a thorough eye examination. These changes typically do not impair vision. | growth_hormone_receptor | in an X-linked pattern |
230 | What are the treatments for Lowe syndrome ? | These resources address the diagnosis or management of Lowe syndrome: - Gene Review: Gene Review: Lowe Syndrome - Genetic Testing Registry: Lowe syndrome - MedlinePlus Encyclopedia: Congenital Cataract - MedlinePlus Encyclopedia: Fanconi 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 | growth_hormone_receptor | Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
231 | What is (are) CATSPER1-related nonsyndromic male infertility ? | CATSPER1-related nonsyndromic male infertility is a condition that affects the function of sperm, leading to an inability to father children. Males with this condition produce sperm that have decreased movement (motility). Affected men may also produce a smaller than usual number of sperm cells or sperm cells that are abnormally shaped. Men with CATSPER1-related nonsyndromic male infertility do not have any other symptoms related to this condition. | growth_hormone_receptor | a condition that affects the function of sperm |
232 | How many people are affected by CATSPER1-related nonsyndromic male infertility ? | The prevalence of CATSPER1-related nonsyndromic male infertility is unknown. | growth_hormone_receptor | unknown |
233 | What are the genetic changes related to CATSPER1-related nonsyndromic male infertility ? | Mutations in the CATSPER1 gene cause CATSPER1-related nonsyndromic male infertility. The CATSPER1 gene provides instructions for producing a protein that is found in the tail of sperm cells. The CATSPER1 protein is involved in the movement of the sperm tail, which propels the sperm forward and is required for sperm cells to push through the outside membrane of the egg cell during fertilization. CATSPER1 gene mutations result in the production of a CATSPER1 protein that may be altered, nonfunctional, or quickly broken down (degraded) by the cell. Sperm cells missing a functional CATSPER1 protein have decreased motion in their tails and move more slowly than normal. Sperm cells lacking functional CATSPER1 protein cannot push through the outside membrane of the egg cell. As a result, sperm cells cannot reach the inside of the egg cell to achieve fertilization. | growth_hormone_receptor | Mutations |
234 | Is CATSPER1-related nonsyndromic male infertility 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 symptoms of the condition. Males with two CATSPER1 gene mutations in each cell have CATSPER1-related nonsyndromic male infertility. Females with two CATSPER1 gene mutations in each cell have no symptoms because the mutations only affect sperm function, and women do not produce sperm. | growth_hormone_receptor | Males with two CATSPER1 gene mutations in each cell |
235 | What are the treatments for CATSPER1-related nonsyndromic male infertility ? | These resources address the diagnosis or management of CATSPER1-related nonsyndromic male infertility: - Cleveland Clinic: Male Infertility - Gene Review: Gene Review: CATSPER-Related Male Infertility - Genetic Testing Registry: CATSPER-Related Male Infertility - MedlinePlus Health Topic: Assisted Reproductive Technology - RESOLVE: The National Infertility Association: 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 | growth_hormone_receptor | diagnosis or management |
236 | What is (are) CHARGE syndrome ? | CHARGE syndrome is a disorder that affects many areas of the body. CHARGE stands for coloboma, heart defect, atresia choanae (also known as choanal atresia), retarded growth and development, genital abnormality, and ear abnormality. The pattern of malformations varies among individuals with this disorder, and infants often have multiple life-threatening medical conditions. The diagnosis of CHARGE syndrome is based on a combination of major and minor characteristics. The major characteristics of CHARGE syndrome are more specific to this disorder than are the minor characteristics. Many individuals with CHARGE syndrome have a hole in one of the structures of the eye (coloboma), which forms during early development. A coloboma may be present in one or both eyes and can affect a person's vision, depending on its size and location. Some people also have small eyes (microphthalmia). One or both nasal passages may be narrowed (choanal stenosis) or completely blocked (choanal atresia). Individuals with CHARGE syndrome frequently have cranial nerve abnormalities. The cranial nerves emerge directly from the brain and extend to various areas of the head and neck, controlling muscle movement and transmitting sensory information. Abnormal function of certain cranial nerves can cause swallowing problems, facial paralysis, a sense of smell that is diminished (hyposmia) or completely absent (anosmia), and mild to profound hearing loss. People with CHARGE syndrome also typically have middle and inner ear abnormalities and unusually shaped ears. The minor characteristics of CHARGE syndrome are not specific to this disorder; they are frequently present in people without CHARGE syndrome. The minor characteristics include heart defects, slow growth starting in late infancy, developmental delay, and an opening in the lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate). Individuals frequently have hypogonadotropic hypogonadism, which affects the production of hormones that direct sexual development. Males are often born with an unusually small penis (micropenis) and undescended testes (cryptorchidism). External genitalia abnormalities are seen less often in females with CHARGE syndrome. Puberty can be incomplete or delayed. Individuals may have a tracheoesophageal fistula, which is an abnormal connection (fistula) between the esophagus and the trachea. People with CHARGE syndrome also have distinctive facial features, including a square-shaped face and difference in the appearance between the right and left sides of the face (facial asymmetry). Individuals have a wide range of cognitive function, from normal intelligence to major learning disabilities with absent speech and poor communication. | growth_hormone_receptor | a disorder that affects many areas of the body |
237 | How many people are affected by CHARGE syndrome ? | CHARGE syndrome occurs in approximately 1 in 8,500 to 10,000 individuals. | growth_hormone_receptor | 1 in 8,500 to 10,000 |
238 | What are the genetic changes related to CHARGE syndrome ? | Mutations in the CHD7 gene cause more than half of all cases of CHARGE syndrome. The CHD7 gene provides instructions for making a protein that most likely regulates gene activity (expression) by a process known as chromatin remodeling. Chromatin is the complex of DNA and protein that packages DNA into chromosomes. The structure of chromatin can be changed (remodeled) to alter how tightly DNA is packaged. Chromatin remodeling is one way gene expression is regulated during development. When DNA is tightly packed, gene expression is lower than when DNA is loosely packed. Most mutations in the CHD7 gene lead to the production of an abnormally short, nonfunctional CHD7 protein, which presumably disrupts chromatin remodeling and the regulation of gene expression. Changes in gene expression during embryonic development likely cause the signs and symptoms of CHARGE syndrome. About one-third of individuals with CHARGE syndrome do not have an identified mutation in the CHD7 gene. Researchers suspect that other genetic and environmental factors may be involved in these individuals. | growth_hormone_receptor | signs and symptoms |
239 | Is CHARGE syndrome inherited ? | CHARGE syndrome 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 CHD7 gene and occur in people with no history of the disorder in their family. In rare cases, an affected person inherits the mutation from an affected parent. | growth_hormone_receptor | in an autosomal dominant pattern |
240 | What are the treatments for CHARGE syndrome ? | These resources address the diagnosis or management of CHARGE syndrome: - Gene Review: Gene Review: CHARGE Syndrome - Genetic Testing Registry: CHARGE association - MedlinePlus Encyclopedia: Choanal atresia - MedlinePlus Encyclopedia: Coloboma - MedlinePlus Encyclopedia: Facial Paralysis 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 | growth_hormone_receptor | diagnosis or management |
241 | What is (are) lysinuric protein intolerance ? | Lysinuric protein intolerance is a disorder caused by the body's inability to digest and use certain protein building blocks (amino acids), namely lysine, arginine, and ornithine. Because the body cannot effectively break down these amino acids, which are found in many protein-rich foods, nausea and vomiting are typically experienced after ingesting protein. People with lysinuric protein intolerance have features associated with protein intolerance, including an enlarged liver and spleen (hepatosplenomegaly), short stature, muscle weakness, impaired immune function, and progressively brittle bones that are prone to fracture (osteoporosis). A lung disorder called pulmonary alveolar proteinosis may also develop. This disorder is characterized by protein deposits in the lungs, which interfere with lung function and can be life-threatening. An accumulation of amino acids in the kidneys can cause end-stage renal disease (ESRD) in which the kidneys become unable to filter fluids and waste products from the body effectively. A lack of certain amino acids can cause elevated levels of ammonia in the blood. If ammonia levels are too high for too long, they can cause coma and intellectual disability. The signs and symptoms of lysinuric protein intolerance typically appear after infants are weaned and receive greater amounts of protein from solid foods. | growth_hormone_receptor | a disorder |
242 | How many people are affected by lysinuric protein intolerance ? | Lysinuric protein intolerance is estimated to occur in 1 in 60,000 newborns in Finland and 1 in 57,000 newborns in Japan. Outside these populations this condition occurs less frequently, but the exact incidence is unknown. | growth_hormone_receptor | 1 in 60,000 |
243 | What are the genetic changes related to lysinuric protein intolerance ? | Mutations in the SLC7A7 gene cause lysinuric protein intolerance. The SLC7A7 gene provides instructions for producing a protein called y+L amino acid transporter 1 (y+LAT-1), which is involved in transporting lysine, arginine, and ornithine between cells in the body. The transportation of amino acids from the small intestines and kidneys to the rest of the body is necessary for the body to be able to use proteins. Mutations in the y+LAT-1 protein disrupt the transportation of amino acids, leading to a shortage of lysine, arginine, and ornithine in the body and an abnormally large amount of these amino acids in urine. A shortage of lysine, arginine, and ornithine disrupts many vital functions. Arginine and ornithine are involved in a cellular process called the urea cycle, which processes excess nitrogen (in the form of ammonia) that is generated when protein is used by the body. The lack of arginine and ornithine in the urea cycle causes elevated levels of ammonia in the blood. Lysine is particularly abundant in collagen molecules that give structure and strength to connective tissues such as skin, tendons, and ligaments. A deficiency of lysine contributes to the short stature and osteoporosis seen in people with lysinuric protein intolerance. Other features of lysinuric protein intolerance are thought to result from abnormal protein transport (such as protein deposits in the lungs) or a lack of protein that can be used by the body (protein malnutrition). | growth_hormone_receptor | abnormal protein transport |
244 | Is lysinuric protein intolerance 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
245 | What are the treatments for lysinuric protein intolerance ? | These resources address the diagnosis or management of lysinuric protein intolerance: - Gene Review: Gene Review: Lysinuric Protein Intolerance - Genetic Testing Registry: Lysinuric protein intolerance - MedlinePlus Encyclopedia: Aminoaciduria - 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 | growth_hormone_receptor | diagnosis or management |
246 | What is (are) cap myopathy ? | Cap myopathy is a disorder that primarily affects skeletal muscles, which are muscles that the body uses for movement. People with cap myopathy have muscle weakness (myopathy) and poor muscle tone (hypotonia) throughout the body, but they are most severely affected in the muscles of the face, neck, and limbs. The muscle weakness, which begins at birth or during childhood, can worsen over time. Affected individuals may have feeding and swallowing difficulties in infancy. They typically have delayed development of motor skills such as sitting, crawling, standing, and walking. They may fall frequently, tire easily, and have difficulty running, climbing stairs, or jumping. In some cases, the muscles used for breathing are affected, and life-threatening breathing difficulties can occur. People with cap myopathy may have a high arch in the roof of the mouth (high-arched palate), severely drooping eyelids (ptosis), and a long face. Some affected individuals develop an abnormally curved lower back (lordosis) or a spine that curves to the side (scoliosis). The name cap myopathy comes from characteristic abnormal cap-like structures that can be seen in muscle cells when muscle tissue is viewed under a microscope. The severity of cap myopathy is related to the percentage of muscle cells that have these caps. Individuals in whom 70 to 75 percent of muscle cells have caps typically have severe breathing problems and may not survive childhood, while those in whom 10 to 30 percent of muscle cells have caps have milder symptoms and can live into adulthood. | growth_hormone_receptor | muscle weakness |
247 | How many people are affected by cap myopathy ? | Cap myopathy is a rare disorder that has been identified in only a small number of individuals. Its exact prevalence is unknown. | growth_hormone_receptor | a small number |
248 | What are the genetic changes related to cap myopathy ? | Mutations in the ACTA1, TPM2, or TPM3 genes can cause cap myopathy. These genes provide instructions for producing proteins that play important roles in skeletal muscles. The ACTA1 gene provides instructions for making a protein called skeletal alpha ()-actin, which is part of the actin protein family. Actin proteins are important for cell movement and the tensing of muscle fibers (muscle contraction). Thin filaments made up of actin molecules and thick filaments made up of another protein called myosin are the primary components of muscle fibers and are important for muscle contraction. Attachment (binding) and release of the overlapping thick and thin filaments allows them to move relative to each other so that the muscles can contract. The mutation in the ACTA1 gene that causes cap myopathy results in an abnormal protein that may interfere with the proper assembly of thin filaments. The cap structures in muscle cells characteristic of this disorder are composed of disorganized thin filaments. The TPM2 and TPM3 genes provide instructions for making proteins that are members of the tropomyosin protein family. Tropomyosin proteins regulate muscle contraction by attaching to actin and controlling its binding to myosin. The specific effects of TPM2 and TPM3 gene mutations are unclear, but researchers suggest they may interfere with normal actin-myosin binding between the thin and thick filaments, impairing muscle contraction and resulting in the muscle weakness that occurs in cap myopathy. | growth_hormone_receptor | muscle weakness |
249 | Is cap myopathy inherited ? | Cap myopathy is an autosomal dominant condition, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases are not inherited; they result from new mutations in the gene and occur in people with no history of the disorder in their family. | growth_hormone_receptor | Most cases are not inherited |
250 | What are the treatments for cap myopathy ? | These resources address the diagnosis or management of cap myopathy: - Genetic Testing Registry: TPM2-related cap myopathy - Genetic Testing Registry: cap myopathy 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 | growth_hormone_receptor | Genetic Testing Registry |
251 | What is (are) pontocerebellar hypoplasia ? | Pontocerebellar hypoplasia is a group of related conditions that affect the development of the brain. The term "pontocerebellar" refers to the pons and the cerebellum, which are the brain structures that are most severely affected in many forms of this disorder. The pons is located at the base of the brain in an area called the brainstem, where it transmits signals between the cerebellum and the rest of the brain. The cerebellum, which is located at the back of the brain, normally coordinates movement. The term "hypoplasia" refers to the underdevelopment of these brain regions. Pontocerebellar hypoplasia also causes impaired growth of other parts of the brain, leading to an unusually small head size (microcephaly). This microcephaly is usually not apparent at birth but becomes noticeable as brain growth continues to be slow in infancy and early childhood. Researchers have described at least ten types of pontocerebellar hypoplasia. All forms of this condition are characterized by impaired brain development, delayed development overall, problems with movement, and intellectual disability. The brain abnormalities are usually present at birth, and in some cases they can be detected before birth. Many children with pontocerebellar hypoplasia live only into infancy or childhood, although some affected individuals have lived into adulthood. The two major forms of pontocerebellar hypoplasia are designated as type 1 (PCH1) and type 2 (PCH2). In addition to the brain abnormalities described above, PCH1 causes problems with muscle movement resulting from a loss of specialized nerve cells called motor neurons in the spinal cord, similar to another genetic disorder known as spinal muscular atrophy. Individuals with PCH1 also have very weak muscle tone (hypotonia), joint deformities called contractures, vision impairment, and breathing and feeding problems that are evident from early infancy. Common features of PCH2 include a lack of voluntary motor skills (such as grasping objects, sitting, or walking), problems with swallowing (dysphagia), and an absence of communication, including speech. Affected children typically develop temporary jitteriness (generalized clonus) in early infancy, abnormal patterns of movement described as chorea or dystonia, and stiffness (spasticity). Many also have impaired vision and seizures. The other forms of pontocerebellar hypoplasia, designated as type 3 (PCH3) through type 10 (PCH10), appear to be rare and have each been reported in only a small number of individuals. Because the different types have overlapping features, and some are caused by mutations in the same genes, researchers have proposed that the types be considered as a spectrum instead of distinct conditions. | growth_hormone_receptor | type 1 (PCH1) and type 2 (PCH2) |
252 | How many people are affected by pontocerebellar hypoplasia ? | The prevalence of pontocerebellar hypoplasia is unknown, although most forms of the disorder appear to be very rare. | growth_hormone_receptor | most forms of the disorder appear to be very rare |
253 | What are the genetic changes related to pontocerebellar hypoplasia ? | Pontocerebellar hypoplasia can result from mutations in several genes. About half of all cases of PCH1 are caused by mutations in the EXOSC3 gene. PCH1 can also result from mutations in several other genes, including TSEN54, RARS2, and VRK1. PCH2 is caused by mutations in the TSEN54, TSEN2, TSEN34, or SEPSECS gene. In addition to causing PCH1 and PCH2, mutations in the TSEN54 gene can cause PCH4 and PCH5. Mutations in the RARS2 gene, in addition to causing PCH1, can result in PCH6. The remaining types of pontocerebellar hypoplasia are caused by mutations in other genes. In some cases, the genetic cause of pontocerebellar hypoplasia is unknown. The genes associated with pontocerebellar hypoplasia appear to play essential roles in the development and survival of nerve cells (neurons). Many of these genes are known or suspected to be involved in processing RNA molecules, which are chemical cousins of DNA. Fully processed, mature RNA molecules are essential for the normal functioning of all cells, including neurons. Studies suggest that abnormal RNA processing likely underlies the abnormal brain development characteristic of pontocerebellar hypoplasia, although the exact mechanism is unknown. Researchers hypothesize that developing neurons in certain areas of the brain may be particularly sensitive to problems with RNA processing. Some of the genes associated with pontocerebellar hypoplasia have functions unrelated to RNA processing. In most cases, it is unclear how mutations in these genes impair brain development. | growth_hormone_receptor | have functions unrelated to RNA processing |
254 | Is pontocerebellar 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
255 | What are the treatments for pontocerebellar hypoplasia ? | These resources address the diagnosis or management of pontocerebellar hypoplasia: - Gene Review: Gene Review: EXOSC3-Related Pontocerebellar Hypoplasia - Gene Review: Gene Review: TSEN54-Related Pontocerebellar Hypoplasia - Genetic Testing Registry: Pontoneocerebellar hypoplasia - 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 | growth_hormone_receptor | diagnosis or management |
256 | What is (are) primary hyperoxaluria ? | Primary hyperoxaluria is a rare condition characterized by recurrent kidney and bladder stones. The condition often results in end stage renal disease (ESRD), which is a life-threatening condition that prevents the kidneys from filtering fluids and waste products from the body effectively. Primary hyperoxaluria results from the overproduction of a substance called oxalate. Oxalate is filtered through the kidneys and excreted as a waste product in urine, leading to abnormally high levels of this substance in urine (hyperoxaluria). During its excretion, oxalate can combine with calcium to form calcium oxalate, a hard compound that is the main component of kidney and bladder stones. Deposits of calcium oxalate can damage the kidneys and other organs and lead to blood in the urine (hematuria), urinary tract infections, kidney damage, ESRD, and injury to other organs. Over time, kidney function decreases such that the kidneys can no longer excrete as much oxalate as they receive. As a result oxalate levels in the blood rise, and the substance gets deposited in tissues throughout the body (systemic oxalosis), particularly in bones and the walls of blood vessels. Oxalosis in bones can cause fractures. There are three types of primary hyperoxaluria that differ in their severity and genetic cause. In primary hyperoxaluria type 1, kidney stones typically begin to appear anytime from childhood to early adulthood, and ESRD can develop at any age. Primary hyperoxaluria type 2 is similar to type 1, but ESRD develops later in life. In primary hyperoxaluria type 3, affected individuals often develop kidney stones in early childhood, but few cases of this type have been described so additional signs and symptoms of this type are unclear. | growth_hormone_receptor | recurrent kidney and bladder stones |
257 | How many people are affected by primary hyperoxaluria ? | Primary hyperoxaluria is estimated to affect 1 in 58,000 individuals worldwide. Type 1 is the most common form, accounting for approximately 80 percent of cases. Types 2 and 3 each account for about 10 percent of cases. | growth_hormone_receptor | 1 in 58,000 |
258 | What are the genetic changes related to primary hyperoxaluria ? | Mutations in the AGXT, GRHPR, and HOGA1 genes cause primary hyperoxaluria types 1, 2, and 3, respectively. These genes provide instructions for making enzymes that are involved in the breakdown and processing of protein building blocks (amino acids) and other compounds. The enzyme produced from the HOGA1 gene is involved in the breakdown of an amino acid, which results in the formation of a compound called glyoxylate. This compound is further broken down by the enzymes produced from the AGXT and GRHPR genes. Mutations in the AGXT, GRHPR, or HOGA1 gene lead to a decrease in production or activity of the respective proteins, which prevents the normal breakdown of glyoxylate. AGXT and GRHPR gene mutations result in an accumulation of glyoxylate, which is then converted to oxalate for removal from the body as a waste product. HOGA1 gene mutations also result in excess oxalate, although researchers are unsure as to how this occurs. Oxalate that is not excreted from the body combines with calcium to form calcium oxalate deposits, which can damage the kidneys and other organs. | growth_hormone_receptor | 1, 2, and 3 |
259 | Is primary hyperoxaluria 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
260 | What are the treatments for primary hyperoxaluria ? | These resources address the diagnosis or management of primary hyperoxaluria: - Gene Review: Gene Review: Primary Hyperoxaluria Type 1 - Gene Review: Gene Review: Primary Hyperoxaluria Type 2 - Gene Review: Gene Review: Primary Hyperoxaluria Type 3 - Genetic Testing Registry: Hyperoxaluria - Genetic Testing Registry: Primary hyperoxaluria 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 | growth_hormone_receptor | Rehabilitation - Genetic Counseling - Palliative Care |
261 | What is (are) propionic acidemia ? | Propionic acidemia is an inherited disorder in which the body is unable to process certain parts of proteins and lipids (fats) properly. It is classified as an organic acid disorder, which is a condition that leads to an abnormal buildup of particular acids known as organic acids. Abnormal levels of organic acids in the blood (organic acidemia), urine (organic aciduria), and tissues can be toxic and can cause serious health problems. In most cases, the features of propionic acidemia become apparent within a few days after birth. The initial symptoms include poor feeding, vomiting, loss of appetite, weak muscle tone (hypotonia), and lack of energy (lethargy). These symptoms sometimes progress to more serious medical problems, including heart abnormalities, seizures, coma, and possibly death. Less commonly, the signs and symptoms of propionic acidemia appear during childhood and may come and go over time. Some affected children experience intellectual disability or delayed development. In children with this later-onset form of the condition, episodes of more serious health problems can be triggered by prolonged periods without food (fasting), fever, or infections. | growth_hormone_receptor | an inherited disorder |
262 | How many people are affected by propionic acidemia ? | Propionic acidemia affects about 1 in 100,000 people in the United States. The condition appears to be more common in several populations worldwide, including the Inuit population of Greenland, some Amish communities, and Saudi Arabians. | growth_hormone_receptor | 1 in 100,000 |
263 | What are the genetic changes related to propionic acidemia ? | Mutations in the PCCA and PCCB genes cause propionic acidemia. The PCCA and PCCB genes provide instructions for making two parts (subunits) of an enzyme called propionyl-CoA carboxylase. This enzyme plays a role in the normal breakdown of proteins. Specifically, it helps process several amino acids, which are the building blocks of proteins. Propionyl-CoA carboxylase also helps break down certain types of fat and cholesterol in the body. Mutations in the PCCA or PCCB gene disrupt the function of the enzyme and prevent the normal breakdown of these molecules. As a result, a substance called propionyl-CoA and other potentially harmful compounds can build up to toxic levels in the body. This buildup damages the brain and nervous system, causing the serious health problems associated with propionic acidemia. | growth_hormone_receptor | Mutations in the PCCA and PCCB genes |
264 | Is propionic acidemia 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. | growth_hormone_receptor | This condition is inherited in an autosomal recessive pattern |
265 | What are the treatments for propionic acidemia ? | These resources address the diagnosis or management of propionic acidemia: - Baby's First Test - Gene Review: Gene Review: Propionic Acidemia - Genetic Testing Registry: Propionic acidemia 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 | growth_hormone_receptor | Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation |
266 | What is (are) Parkes Weber syndrome ? | Parkes Weber syndrome is a disorder of the vascular system, which is the body's complex network of blood vessels. The vascular system consists of arteries, which carry oxygen-rich blood from the heart to the body's various organs and tissues; veins, which carry blood back to the heart; and capillaries, which are tiny blood vessels that connect arteries and veins. Parkes Weber syndrome is characterized by vascular abnormalities known as capillary malformations and arteriovenous fistulas (AVFs), which are present from birth. The capillary malformations increase blood flow near the surface of the skin. They usually look like large, flat, pink stains on the skin, and because of their color are sometimes called "port-wine stains." In people with Parkes Weber syndrome, capillary malformations occur together with multiple micro-AVFs, which are tiny abnormal connections between arteries and veins that affect blood circulation. These AVFs can be associated with life-threatening complications including abnormal bleeding and heart failure. Another characteristic feature of Parkes Weber syndrome is overgrowth of one limb, most commonly a leg. Abnormal growth occurs in bones and soft tissues, making one of the limbs longer and larger around than the corresponding one. Some vascular abnormalities seen in Parkes Weber syndrome are similar to those that occur in a condition called capillary malformation-arteriovenous malformation syndrome (CM-AVM). CM-AVM and some cases of Parkes Weber syndrome have the same genetic cause. | growth_hormone_receptor | a disorder of the vascular system |
267 | How many people are affected by Parkes Weber syndrome ? | Parkes Weber syndrome is a rare condition; its exact prevalence is unknown. | growth_hormone_receptor | unknown |
268 | What are the genetic changes related to Parkes Weber syndrome ? | Some cases of Parkes Weber syndrome result from mutations in the RASA1 gene. When the condition is caused by RASA1 gene mutations, affected individuals usually have multiple capillary malformations. People with Parkes Weber syndrome who do not have multiple capillary malformations are unlikely to have mutations in the RASA1 gene; in these cases, the cause of the condition is often unknown. The RASA1 gene provides instructions for making a protein known as p120-RasGAP, which is involved in transmitting chemical signals from outside the cell to the nucleus. These signals help control several important cell functions, including the growth and division (proliferation) of cells, the process by which cells mature to carry out specific functions (differentiation), and cell movement. The role of the p120-RasGAP protein is not fully understood, although it appears to be essential for the normal development of the vascular system. Mutations in the RASA1 gene lead to the production of a nonfunctional version of the p120-RasGAP protein. A loss of this protein's activity disrupts tightly regulated chemical signaling during development. However, it is unclear how these changes lead to the specific vascular abnormalities and limb overgrowth seen in people with Parkes Weber syndrome. | growth_hormone_receptor | vascular abnormalities and limb overgrowth |
269 | Is Parkes Weber syndrome inherited ? | Most cases of Parkes Weber syndrome occur in people with no history of the condition in their family. These cases are described as sporadic. When Parkes Weber syndrome is caused by mutations in the RASA1 gene, it is sometimes inherited from an affected parent. In these cases, the condition has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. | growth_hormone_receptor | it is sometimes inherited from an affected parent |
270 | What are the treatments for Parkes Weber syndrome ? | These resources address the diagnosis or management of Parkes Weber syndrome: - Gene Review: Gene Review: RASA1-Related Disorders - Genetic Testing Registry: Parkes Weber 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 | growth_hormone_receptor | Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
271 | What is (are) Adams-Oliver syndrome ? | Adams-Oliver syndrome is a rare condition that is present at birth. The primary features are an abnormality in skin development (called aplasia cutis congenita) and malformations of the limbs. A variety of other features can occur in people with Adams-Oliver syndrome. Most people with Adams-Oliver syndrome have aplasia cutis congenita, a condition characterized by localized areas of missing skin typically occurring on the top of the head (the skull vertex). In some cases, the bone under the skin is also underdeveloped. Individuals with this condition commonly have scarring and an absence of hair growth in the affected area. Abnormalities of the hands and feet are also common in people with Adams-Oliver syndrome. These most often involve the fingers and toes and can include abnormal nails, fingers or toes that are fused together (syndactyly), and abnormally short or missing fingers or toes (brachydactyly or oligodactyly). In some cases, other bones in the hands, feet, or lower limbs are malformed or missing. Some affected infants have a condition called cutis marmorata telangiectatica congenita. This disorder of the blood vessels causes a reddish or purplish net-like pattern on the skin. In addition, people with Adams-Oliver syndrome can develop high blood pressure in the blood vessels between the heart and the lungs (pulmonary hypertension), which can be life-threatening. Other blood vessel problems and heart defects can occur in affected individuals. In some cases, people with Adams-Oliver syndrome have neurological problems, such as developmental delay, learning disabilities, or abnormalities in the structure of the brain. | growth_hormone_receptor | a rare condition that is present at birth |
272 | How many people are affected by Adams-Oliver syndrome ? | Adams-Oliver syndrome is a rare disorder; its prevalence is unknown. | growth_hormone_receptor | unknown |
273 | What are the genetic changes related to Adams-Oliver syndrome ? | Mutations in the ARHGAP31, DLL4, DOCK6, EOGT, NOTCH1, or RBPJ gene can cause Adams-Oliver syndrome. Because some affected individuals do not have mutations in one of these genes, it is likely that other genes that have not been identified are also involved in this condition. Each of the known genes plays an important role during embryonic development, and changes in any one of them can impair this tightly controlled process, leading to the signs and symptoms of Adams-Oliver syndrome. The proteins produced from the ARHGAP31 and DOCK6 genes are both involved in the regulation of proteins called GTPases, which transmit signals that are critical for various aspects of embryonic development. The ARHGAP31 and DOCK6 proteins appear to be especially important for GTPase regulation during development of the limbs, skull, and heart. GTPases are often called molecular switches because they can be turned on and off. The DOCK6 protein turns them on, and the ARHGAP31 protein turns them off. Mutations in the DOCK6 gene lead to production of an abnormally short DOCK6 protein that is likely unable to turn on GTPases, which reduces their activity. Mutations in the ARHGAP31 gene also decrease GTPase activity by leading to production of an abnormally active ARHGAP31 protein, which turns off GTPases when it normally would not. This decline in GTPase activity leads to the skin problems, bone malformations, and other features characteristic of Adams-Oliver syndrome. The proteins produced from the NOTCH1, DLL4, and RBPJ genes are part of a signaling pathway known as the Notch pathway. Notch signaling controls how certain types of cells develop in the growing embryo, including those that form the bones, heart, muscles, nerves, and blood vessels. The Notch1 and DLL4 proteins fit together like a lock and its key to stimulate one part of the Notch pathway, which is important for development of blood vessels. The NOTCH1 and DLL4 gene mutations involved in Adams-Oliver syndrome likely impair Notch1 signaling, which may underlie blood vessel and heart abnormalities in some people with Adams-Oliver syndrome. Researchers suspect that the other features of the condition may be due to abnormal blood vessel development before birth. Signaling through Notch1 and other Notch proteins stimulates the RBP-J protein, produced from the RBPJ gene, to attach (bind) to specific regions of DNA and control the activity of genes that play a role in cellular development in multiple tissues throughout the body. The RBPJ gene mutations involved in Adams-Oliver syndrome alter the region of the RBP-J protein that normally binds DNA. The altered protein is unable to bind to DNA, preventing it from turning on particular genes. These changes in gene activity impair the proper development of the skin, bones, and other tissues, leading to the features of Adams-Oliver syndrome. Little is known about how mutations in the EOGT gene cause Adams-Oliver syndrome. The protein produced from this gene modifies certain proteins by transferring a molecule called N-acetylglucosamine to them. It is thought that the EOGT protein modifies Notch proteins, which stimulate the Notch signaling pathway. However, the impact of the modification on Notch signaling is unclear. At least three mutations in the EOGT gene have been identified in people with Adams-Oliver syndrome, but how the genetic changes contribute to the signs and symptoms of this disorder is still unknown. | growth_hormone_receptor | signs and symptoms of this disorder is still unknown |
274 | Is Adams-Oliver syndrome inherited ? | Adams-Oliver syndrome can have different inheritance patterns. When caused by mutations in the ARHGAP31, DLL4, NOTCH1, or RBPJ gene, the condition is inherited in an autosomal dominant pattern. Autosomal dominant inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. The altered gene is typically inherited from an affected parent. Some cases associated with NOTCH1 gene mutations result from new (de novo) mutations in the gene that occur during the formation of reproductive cells (eggs or sperm) or in early embryonic development. These cases occur in people with no history of the disorder in their family. When caused by mutations in the DOCK6 or EOGT gene, Adams-Oliver syndrome is inherited in an autosomal recessive pattern. In conditions with this pattern of 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. | growth_hormone_receptor | Adams-Oliver syndrome is inherited in an autosomal recessive pattern |
275 | What are the treatments for Adams-Oliver syndrome ? | These resources address the diagnosis or management of Adams-Oliver syndrome: - Contact a Family - Gene Review: Gene Review: Adams-Oliver Syndrome - Genetic Testing Registry: Adams-Oliver syndrome - Genetic Testing Registry: Adams-Oliver syndrome 5 - Genetic Testing Registry: Adams-Oliver syndrome 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 | growth_hormone_receptor | Diagnostic Tests - Drug Therapy - Surgery |
276 | What is (are) Paget disease of bone ? | Paget disease of bone is a disorder that causes bones to grow larger and weaker than normal. Affected bones may be misshapen and easily broken (fractured). The classic form of Paget disease of bone typically appears in middle age or later. It usually occurs in one or a few bones and does not spread from one bone to another. Any bones can be affected, although the disease most commonly affects bones in the spine, pelvis, skull, or legs. Many people with classic Paget disease of bone do not experience any symptoms associated with their bone abnormalities. The disease is often diagnosed unexpectedly by x-rays or laboratory tests done for other reasons. People who develop symptoms are most likely to experience pain. The affected bones may themselves be painful, or pain may be caused by arthritis in nearby joints. Arthritis results when the distortion of bones, particularly weight-bearing bones in the legs, causes extra wear and tear on the joints. Arthritis most frequently affects the knees and hips in people with this disease. Other complications of Paget disease of bone depend on which bones are affected. If the disease occurs in bones of the skull, it can cause an enlarged head, hearing loss, headaches, and dizziness. If the disease affects bones in the spine, it can lead to numbness and tingling (due to pinched nerves) and abnormal spinal curvature. In the leg bones, the disease can cause bowed legs and difficulty walking. A rare type of bone cancer called osteosarcoma has been associated with Paget disease of bone. This type of cancer probably occurs in less than 1 in 1,000 people with this disease. Early-onset Paget disease of bone is a less common form of the disease that appears in a person's teens or twenties. Its features are similar to those of the classic form of the disease, although it is more likely to affect the skull, spine, and ribs (the axial skeleton) and the small bones of the hands. The early-onset form of the disorder is also associated with hearing loss early in life. | growth_hormone_receptor | osteosarcoma |
277 | How many people are affected by Paget disease of bone ? | Classic Paget disease of bone occurs in approximately 1 percent of people older than 40 in the United States. Scientists estimate that about 1 million people in this country have the disease. It is most common in people of western European heritage. Early-onset Paget disease of bone is much rarer. This form of the disorder has been reported in only a few families. | growth_hormone_receptor | 1 million |
278 | What are the genetic changes related to Paget disease of bone ? | A combination of genetic and environmental factors likely play a role in causing Paget disease of bone. Researchers have identified changes in several genes that increase the risk of the disorder. Other factors, including infections with certain viruses, may be involved in triggering the disease in people who are at risk. However, the influence of genetic and environmental factors on the development of Paget disease of bone remains unclear. Researchers have identified variations in three genes that are associated with Paget disease of bone: SQSTM1, TNFRSF11A, and TNFRSF11B. Mutations in the SQSTM1 gene are the most common genetic cause of classic Paget disease of bone, accounting for 10 to 50 percent of cases that run in families and 5 to 30 percent of cases in which there is no family history of the disease. Variations in the TNFRSF11B gene also appear to increase the risk of the classic form of the disorder, particularly in women. TNFRSF11A mutations cause the early-onset form of Paget disease of bone. The SQSTM1, TNFRSF11A, and TNFRSF11B genes are 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. Paget disease of bone disrupts the bone remodeling process. Affected bone is broken down abnormally and then replaced much faster than usual. When the new bone tissue grows, it is larger, weaker, and less organized than normal bone. It is unclear why these problems with bone remodeling affect some bones but not others in people with this disease. Researchers are looking for additional genes that may influence a person's chances of developing Paget disease of bone. Studies suggest that genetic variations in certain regions of chromosome 2, chromosome 5, and chromosome 10 appear to contribute to disease risk. However, the associated genes on these chromosomes have not been identified. | growth_hormone_receptor | chromosome 2, chromosome 5, and chromosome 10 |
279 | Is Paget disease of bone inherited ? | In 15 to 40 percent of all cases of classic Paget disease of bone, the disorder has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means that having one copy of an altered gene in each cell is sufficient to cause the disorder. In the remaining cases, the inheritance pattern of classic Paget disease of bone is unclear. Many affected people have no family history of the disease, although it sometimes clusters in families. Studies suggest that close relatives of people with classic Paget disease of bone are 7 to 10 times more likely to develop the disease than people without an affected relative. Early-onset Paget disease of bone is inherited in an autosomal dominant pattern. In people with this form of the disorder, having one altered copy of the TNFRSF11A gene in each cell is sufficient to cause the disease. | growth_hormone_receptor | in an autosomal dominant pattern |
280 | What are the treatments for Paget disease of bone ? | These resources address the diagnosis or management of Paget disease of bone: - Genetic Testing Registry: Osteitis deformans - Genetic Testing Registry: Paget disease of bone 4 - Genetic Testing Registry: Paget disease of bone, familial - MedlinePlus Encyclopedia: Paget's Disease of the Bone 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 | growth_hormone_receptor | 4 - Genetic Testing Registry |
281 | What is (are) trisomy 13 ? | Trisomy 13, also called Patau syndrome, is a chromosomal condition associated with severe intellectual disability and physical abnormalities in many parts of the body. Individuals with trisomy 13 often have heart defects, brain or spinal cord abnormalities, very small or poorly developed eyes (microphthalmia), extra fingers or toes, an opening in the lip (a cleft lip) with or without an opening in the roof of the mouth (a cleft palate), and weak muscle tone (hypotonia). Due to the presence of several life-threatening medical problems, many infants with trisomy 13 die within their first days or weeks of life. Only five percent to 10 percent of children with this condition live past their first year. | growth_hormone_receptor | a chromosomal condition |
282 | How many people are affected by trisomy 13 ? | Trisomy 13 occurs in about 1 in 16,000 newborns. Although women of any age can have a child with trisomy 13, the chance of having a child with this condition increases as a woman gets older. | growth_hormone_receptor | 1 in 16,000 |
283 | What are the genetic changes related to trisomy 13 ? | Most cases of trisomy 13 result from having three copies of chromosome 13 in each cell in the body instead of the usual two copies. The extra genetic material disrupts the normal course of development, causing the characteristic features of trisomy 13. Trisomy 13 can also occur when part of chromosome 13 becomes attached (translocated) to another chromosome during the formation of reproductive cells (eggs and sperm) or very early in fetal development. Affected people have two normal copies of chromosome 13, plus an extra copy of chromosome 13 attached to another chromosome. In rare cases, only part of chromosome 13 is present in three copies. The physical signs and symptoms in these cases may be different than those found in full trisomy 13. A small percentage of people with trisomy 13 have an extra copy of chromosome 13 in only some of the body's cells. In these people, the condition is called mosaic trisomy 13. The severity of mosaic trisomy 13 depends on the type and number of cells that have the extra chromosome. The physical features of mosaic trisomy 13 are often milder than those of full trisomy 13. | growth_hormone_receptor | The extra genetic material disrupts the normal course of development |
284 | Is trisomy 13 inherited ? | Most cases of trisomy 13 are not inherited and result from random events during the formation of eggs and sperm in healthy parents. An error in cell division called nondisjunction results in a reproductive cell with an abnormal number of chromosomes. For example, an egg or sperm cell may gain an extra copy of chromosome 13. If one of these atypical reproductive cells contributes to the genetic makeup of a child, the child will have an extra chromosome 13 in each cell of the body. Translocation trisomy 13 can be inherited. An unaffected person can carry a rearrangement of genetic material between chromosome 13 and another chromosome. These rearrangements are called balanced translocations because there is no extra material from chromosome 13. A person with a balanced translocation involving chromosome 13 has an increased chance of passing extra material from chromosome 13 to their children. | growth_hormone_receptor | Most cases of trisomy 13 are not inherited |
285 | What are the treatments for trisomy 13 ? | These resources address the diagnosis or management of trisomy 13: - Genetic Testing Registry: Complete trisomy 13 syndrome - MedlinePlus Encyclopedia: Trisomy 13 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 | growth_hormone_receptor | Surgery and Rehabilitation - Genetic Counseling - Palliative Care |
286 | What is (are) Aicardi syndrome ? | Aicardi syndrome is a disorder that occurs almost exclusively in females. It is characterized by three main features that occur together in most affected individuals. People with Aicardi syndrome have absent or underdeveloped tissue connecting the left and right halves of the brain (agenesis or dysgenesis of the corpus callosum). They have seizures beginning in infancy (infantile spasms), which tend to progress to recurrent seizures (epilepsy) that can be difficult to treat. Affected individuals also have chorioretinal lacunae, which are defects in the light-sensitive tissue at the back of the eye (retina). People with Aicardi syndrome often have additional brain abnormalities, including asymmetry between the two sides of the brain, brain folds and grooves that are small in size or reduced in number, cysts, and enlargement of the fluid-filled cavities (ventricles) near the center of the brain. Some have an unusually small head (microcephaly). Most affected individuals have moderate to severe developmental delay and intellectual disability, although some people with this disorder have milder disability. In addition to chorioretinal lacunae, people with Aicardi syndrome may have other eye abnormalities such as small or poorly developed eyes (microphthalmia) or a gap or hole (coloboma) in the optic nerve, a structure that carries information from the eye to the brain. These eye abnormalities may cause blindness in affected individuals. Some people with Aicardi syndrome have unusual facial features including a short area between the upper lip and the nose (philtrum), a flat nose with an upturned tip, large ears, and sparse eyebrows. Other features of this condition include small hands, hand malformations, and spinal and rib abnormalities leading to progressive abnormal curvature of the spine (scoliosis). They often have gastrointestinal problems such as constipation or diarrhea, gastroesophageal reflux, and difficulty feeding. The severity of Aicardi syndrome varies. Some people with this disorder have very severe epilepsy and may not survive past childhood. Less severely affected individuals may live into adulthood with milder signs and symptoms. | growth_hormone_receptor | a disorder that occurs almost exclusively in females |
287 | How many people are affected by Aicardi syndrome ? | Aicardi syndrome is a very rare disorder. It occurs in about 1 in 105,000 to 167,000 newborns in the United States. Researchers estimate that there are approximately 4,000 affected individuals worldwide. | growth_hormone_receptor | 4,000 |
288 | What are the genetic changes related to Aicardi syndrome ? | The cause of Aicardi syndrome is unknown. Because it occurs almost exclusively in females, researchers believe that it is probably the result of a mutation in a gene on the X chromosome. People normally have 46 chromosomes in each cell. Two of the 46 chromosomes, known as X and Y, are called sex chromosomes because they help determine whether a person will develop male or female sex characteristics. Genes on these chromosomes are also involved in other functions in the body. Females typically have two X chromosomes (46,XX), and males have one X chromosome and one Y chromosome (46,XY). Early in embryonic development in females, one of the two X chromosomes is permanently inactivated in somatic cells (cells other than egg and sperm cells). X-inactivation ensures that females, like males, have only one active copy of the X chromosome in each body cell. Usually X-inactivation occurs randomly, so that each X chromosome is active in about half the body's cells. Sometimes X-inactivation is not random, and one X chromosome is active in more than half of cells. When X-inactivation does not occur randomly, it is called skewed X-inactivation. Skewed X-inactivation sometimes occurs when there is a severe gene mutation in one of the X chromosomes in each cell. Because the cells where this chromosome is active will not be able to survive as well, X-inactivation will appear to be skewed. Skewed X-inactivation has been identified in girls with Aicardi syndrome, further supporting the idea that the disorder is caused by a mutation in a gene on the X chromosome. However, this gene has not been identified, and it is unknown how the genetic change that causes Aicardi syndrome results in the various signs and symptoms of this disorder. | growth_hormone_receptor | various signs and symptoms |
289 | Is Aicardi syndrome inherited ? | Nearly all known cases of Aicardi syndrome are sporadic, which means that they are not passed down through generations and occur in people with no history of the disorder in their family. The disorder is believed to result from new gene mutations. Aicardi syndrome is classified as an X-linked dominant condition. While the gene associated with this disorder is not known, it is believed to be located on the X chromosome. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell is sufficient to cause the disorder. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell is nearly always lethal very early in development, so almost all babies with Aicardi syndrome are female. However, a few affected males with an extra copy of the X chromosome in each cell (47,XXY) have been identified. Males with a 47,XXY chromosome pattern also have a condition called Klinefelter syndrome. | growth_hormone_receptor | they are not passed down through generations |
290 | What are the treatments for Aicardi syndrome ? | These resources address the diagnosis or management of Aicardi syndrome: - Baylor College of Medicine - Gene Review: Gene Review: Aicardi Syndrome - Genetic Testing Registry: Aicardi's 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 | growth_hormone_receptor | Diagnostic Tests |
291 | What is (are) Tietz syndrome ? | Tietz syndrome is a disorder characterized by profound hearing loss from birth, fair skin, and light-colored hair. The hearing loss in affected individuals is caused by abnormalities of the inner ear (sensorineural hearing loss) and is present from birth. Although people with Tietz syndrome are born with white hair and very pale skin, their hair color often darkens over time to blond or red. The skin of affected individuals, which sunburns very easily, may tan slightly or develop reddish freckles with limited sun exposure; however, their skin and hair color remain lighter than those of other members of their family. Tietz syndrome also affects the eyes. The colored part of the eye (the iris) in affected individuals is blue, and specialized cells in the eye called retinal pigment epithelial cells lack their normal pigment. The retinal pigment epithelium nourishes the retina, the part of the eye that detects light and color. The changes to the retinal pigment epithelium are generally detectable only by an eye examination; it is unclear whether the changes affect vision. | growth_hormone_receptor | profound hearing loss from birth, fair skin, and light-colored hair |
292 | How many people are affected by Tietz syndrome ? | Tietz syndrome is a rare disorder; its exact prevalence is unknown. Only a few affected families have been described in the medical literature. | growth_hormone_receptor | a few |
293 | What are the genetic changes related to Tietz syndrome ? | Tietz syndrome is caused by mutations in the MITF gene. This gene provides instructions for making a protein that plays a role in the development, survival, and function of certain types of cells. Molecules of the MITF protein attach (bind) to each other or with other proteins that have a similar structure, creating a two-protein unit (dimer). The dimer attaches to specific areas of DNA and helps control the activity of particular genes. On the basis of this action, the MITF protein is called a transcription factor. The MITF protein helps control the development and function of pigment-producing cells called melanocytes. Within these cells, this protein controls production of the pigment melanin, which contributes to hair, eye, and skin color. Melanocytes are also found in the inner ear and play an important role in hearing. Additionally, the MITF protein regulates the development of the retinal pigment epithelium. MITF gene mutations that cause Tietz syndrome either delete or change a single protein building block (amino acid) in an area of the MITF protein known as the basic motif region. Dimers incorporating the abnormal MITF protein cannot be transported into the cell nucleus to bind with DNA. As a result, most of the dimers are unavailable to bind to DNA, which affects the development of melanocytes and the production of melanin. The resulting reduction or absence of melanocytes in the inner ear leads to hearing loss. Decreased melanin production (hypopigmentation) accounts for the light skin and hair color and the retinal pigment epithelium changes that are characteristic of Tietz syndrome. Researchers suggest that Tietz syndrome may represent a severe form of a disorder called Waardenburg syndrome, which can also be caused by MITF gene mutations. | growth_hormone_receptor | retinal pigment epithelium changes |
294 | Is Tietz syndrome inherited ? | This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition. | growth_hormone_receptor | This condition is inherited in an autosomal dominant pattern |
295 | What are the treatments for Tietz syndrome ? | These resources address the diagnosis or management of Tietz syndrome: - Genetic Testing Registry: Tietz 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 | growth_hormone_receptor | Genetic Testing Registry |
296 | What is (are) Tangier disease ? | Tangier disease is an inherited disorder characterized by significantly reduced levels of high-density lipoprotein (HDL) in the blood. HDL transports cholesterol and certain fats called phospholipids from the body's tissues to the liver, where they are removed from the blood. HDL is often referred to as "good cholesterol" because high levels of this substance reduce the chances of developing heart and blood vessel (cardiovascular) disease. Because people with Tangier disease have very low levels of HDL, they have a moderately increased risk of cardiovascular disease. Additional signs and symptoms of Tangier disease include a slightly elevated amount of fat in the blood (mild hypertriglyceridemia); disturbances in nerve function (neuropathy); and enlarged, orange-colored tonsils. Affected individuals often develop atherosclerosis, which is an accumulation of fatty deposits and scar-like tissue in the lining of the arteries. Other features of this condition may include an enlarged spleen (splenomegaly), an enlarged liver (hepatomegaly), clouding of the clear covering of the eye (corneal clouding), and type 2 diabetes. | growth_hormone_receptor | an inherited disorder |
297 | How many people are affected by Tangier disease ? | Tangier disease is a rare disorder with approximately 100 cases identified worldwide. More cases are likely undiagnosed. This condition is named after an island off the coast of Virginia where the first affected individuals were identified. | growth_hormone_receptor | 100 |
298 | What are the genetic changes related to Tangier disease ? | Mutations in the ABCA1 gene cause Tangier disease. This gene provides instructions for making a protein that releases cholesterol and phospholipids from cells. These substances are used to make HDL, which transports them to the liver. Mutations in the ABCA1 gene prevent the release of cholesterol and phospholipids from cells. As a result, these substances accumulate within cells, causing certain body tissues to enlarge and the tonsils to acquire a yellowish-orange color. A buildup of cholesterol can be toxic to cells, leading to impaired cell function or cell death. In addition, the inability to transport cholesterol and phospholipids out of cells results in very low HDL levels, which increases the risk of cardiovascular disease. These combined factors cause the signs and symptoms of Tangier disease. | growth_hormone_receptor | signs and symptoms |
299 | Is Tangier 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. | growth_hormone_receptor | autosomal recessive pattern |
300 | What are the treatments for Tangier disease ? | These resources address the diagnosis or management of Tangier disease: - Genetic Testing Registry: Tangier 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 | growth_hormone_receptor | Genetic Testing Registry |