bowang0911/MedQuAD huggingface dataset:
The genetic causes of Russell-Silver syndrome are complex. The disorder often results from the abnormal regulation of certain genes that control growth. Research has focused on genes located in particular regions of chromosome 7 and chromosome 11.  People normally inherit one copy of each chromosome from their mother and one copy from their father. For most genes, both copies are expressed, or "turned on," in cells. For some genes, however, only the copy inherited from a person's father (the paternal copy) is expressed. For other genes, only the copy inherited from a person's mother (the maternal copy) is expressed. These parent-specific differences in gene expression are caused by a phenomenon called genomic imprinting. Both chromosome 7 and chromosome 11 contain groups of genes that normally undergo genomic imprinting. Abnormalities involving these genes appear to be responsible for many cases of Russell-Silver syndrome.  Researchers suspect that at least one third of all cases of Russell-Silver syndrome result from changes in a process called methylation. Methylation is a chemical reaction that attaches small molecules called methyl groups to certain segments of DNA. In genes that undergo genomic imprinting, methylation is one way that a gene's parent of origin is marked during the formation of egg and sperm cells. Russell-Silver syndrome has been associated with changes in methylation involving the H19 and IGF2 genes, which are located near one another on chromosome 11. These genes are thought to be involved in directing normal growth. A loss of methylation disrupts the regulation of these genes, which leads to slow growth and the other characteristic features of this disorder.  Abnormalities involving genes on chromosome 7 also cause Russell-Silver syndrome. In 7 percent to 10 percent of cases, people inherit both copies of chromosome 7 from their mother instead of one copy from each parent. This phenomenon is called maternal uniparental disomy (UPD). Maternal UPD causes people to have two active copies of maternally expressed imprinted genes rather than one active copy from the mother and one inactive copy from the father. These individuals do not have a paternal copy of chromosome 7 and therefore do not have any copies of genes that are active only on the paternal copy. In cases of Russell-Silver syndrome caused by maternal UPD, an imbalance in active paternal and maternal genes on chromosome 7 underlies the signs and symptoms of the disorder.  In at least 40 percent of people with Russell-Silver syndrome, the cause of the condition is unknown. It is possible that changes in chromosomes other than 7 and 11 may play a role. Researchers are working to identify additional genetic changes that underlie this disorder.
Most cases of Russell-Silver syndrome are sporadic, which means they occur in people with no history of the disorder in their family.  Less commonly, Russell-Silver syndrome can run in families. In some affected families, the condition appears to have an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of a genetic change in each cell is sufficient to cause the disorder. In other families, the condition has an autosomal recessive pattern of inheritance. Autosomal recessive inheritance means both copies of a gene are altered in each cell. 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.
These resources address the diagnosis or management of Russell-Silver syndrome:  - Gene Review: Gene Review: Russell-Silver Syndrome  - Genetic Testing Registry: Russell-Silver syndrome  - MedlinePlus Encyclopedia: Russell-Silver 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
Hennekam syndrome is an inherited disorder resulting from malformation of the lymphatic system, which is part of both the circulatory system and immune system. The lymphatic system consists of a network of vessels that transport lymph fluid and immune cells throughout the body.  The characteristic signs and symptoms of Hennekam syndrome are lymphatic vessels that are abnormally expanded (lymphangiectasia), particularly the vessels that transport lymph fluid to and from the intestines; puffiness or swelling caused by a buildup of fluid (lymphedema); and unusual facial features.  Lymphangiectasia often impedes the flow of lymph fluid and can cause the affected vessels to break open (rupture). In the intestines, ruptured vessels can lead to accumulation of lymph fluid, which interferes with the absorption of nutrients, fats, and proteins. Accumulation of lymph fluid in the abdomen can cause swelling (chylous ascites). Lymphangiectasia can also affect the kidneys, thyroid gland, the outer covering of the lungs (the pleura), the membrane covering the heart (pericardium), or the skin.  The lymphedema in Hennekam syndrome is often noticeable at birth and usually affects the face and limbs. Severely affected infants may have extensive swelling caused by fluid accumulation before birth (hydrops fetalis). The lymphedema usually affects one side of the body more severely than the other (asymmetric) and slowly worsens over time.  Facial features of people with Hennekam syndrome may include a flattened appearance to the middle of the face and the bridge of the nose, puffy eyelids, widely spaced eyes (hypertelorism), small ears, and a small mouth with overgrowth of the gums (gingival hypertrophy). Affected individuals may also have an unusually small head (microcephaly) and premature fusion of the skull bones (craniosynostosis).  Individuals with Hennekam syndrome often have intellectual disability that ranges from mild to severe, although most are on the mild end of the range and some have normal intellect. Many individuals with Hennekam syndrome have growth delay, respiratory problems, permanently bent fingers and toes (camptodactyly), or fusion of the skin between the fingers and toes (cutaneous syndactyly).  Abnormalities found in a few individuals with Hennekam syndrome include a moderate to severe shortage of red blood cells (anemia) resulting from an inadequate amount (deficiency) of iron in the bloodstream, multiple spleens (polysplenia), misplaced kidneys, genital anomalies, a soft out-pouching around the belly-button (umbilical hernia), heart abnormalities, hearing loss, excessive body hair growth (hirsutism), a narrow upper chest that may have a sunken appearance (pectus excavatum), an abnormal side-to-side curvature of the spine (scoliosis), and inward- and upward-turning feet (clubfeet).  The signs and symptoms of Hennekam syndrome vary widely among affected individuals, even those within the same family. Life expectancy depends on the severity of the condition and can vary from death in childhood to survival into adulthood.
Mutations in the CCBE1 or FAT4 gene can cause Hennekam syndrome.  The CCBE1 gene provides instructions for making a protein that is found in the lattice of proteins and other molecules outside the cell (extracellular matrix). The CCBE1 protein is involved in the maturation (differentiation) and movement (migration) of immature cells called lymphangioblasts that will eventually form the lining (epithelium) of lymphatic vessels.  The function of the protein produced from the FAT4 gene is largely unknown. Research shows that the FAT4 protein may be involved in determining the position of various components within cells (cell polarity).  CCBE1 gene mutations that cause Hennekam syndrome change the three-dimensional shape of the protein and severely decrease its function. The abnormal protein cannot play its role in the formation of the lymphatic vessel epithelium. The resulting malformation of lymphatic vessels leads to lymphangiectasia, lymphedema, and other features of Hennekam syndrome. Since the lymphatic system extends throughout the body, a disruption to the vessels can affect almost any organ. Altered lymphatic development before birth may change the balance of fluids and impair normal development, contributing to many of the other signs of Hennekam syndrome such as unusual facial features.  FAT4 gene mutations that cause Hennekam syndrome result in a FAT4 protein with decreased function. Reduced FAT4 protein activity seems to impair normal development of the lymphatic system, but the mechanism is unknown.  Together, mutations in the CCBE1 and FAT4 genes are responsible for approximately half of all Hennekam syndrome cases. The cause of the remaining cases is unknown.
These resources address the diagnosis or management of Hennekam syndrome:  - Great Ormond Street Hospital for Children (UK): Primary Intestinal Lymphangiectasia Information  - Johns Hopkins Medicine: Lymphedema Management  - VascularWeb: Lymphedema   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
Eosinophil peroxidase deficiency is a condition that affects certain white blood cells called eosinophils but causes no health problems in affected individuals. Eosinophils aid in the body's immune response. During a normal immune response, these cells are turned on (activated), and they travel to the area of injury or inflammation. The cells then release proteins and other compounds that have a toxic effect on severely damaged cells or invading organisms. One of these proteins is called eosinophil peroxidase. In eosinophil peroxidase deficiency, eosinophils have little or no eosinophil peroxidase. A lack of this protein does not seem to affect the eosinophils' ability to carry out an immune response.  Because eosinophil peroxidase deficiency does not cause any health problems, this condition is often diagnosed when blood tests are done for other reasons or when a family member has been diagnosed with the condition.
Approximately 100 individuals with eosinophil peroxidase deficiency have been described in the scientific literature. Based on blood test data, varying estimates of the prevalence of the condition have been reported in specific populations. Eosinophil peroxidase deficiency is estimated to occur in 8.6 in 1,000 Yemenite Jews, in 3 in 1,000 North-African Jews, and in 1 in 1,000 Iraqi Jews. In northeastern Italy, the condition occurs in approximately 1 in 14,000 individuals; in Japan it occurs in 1 in 36,000 people; and in Luxembourg, eosinophil peroxidase deficiency is thought to occur in 1 in 100,000 people.
Mutations in the EPX gene cause eosinophil peroxidase deficiency. The EPX gene provides instructions for making the eosinophil peroxidase protein. During an immune response, activated eosinophils release eosinophil peroxidase at the site of injury. This protein helps form molecules that are highly toxic to bacteria and parasites. These toxic molecules also play a role in regulating inflammation by fighting microbial invaders.  EPX gene mutations reduce or prevent eosinophil peroxidase production or result in a protein that is unstable and nonfunctional. As a result, eosinophils have severely reduced amounts of eosinophil peroxidase or none at all. Other proteins within affected eosinophils are normal, and while the cells lacking eosinophil peroxidase are smaller and may have structural changes, the loss of eosinophil peroxidase does not appear to impair the function of eosinophils.
These resources address the diagnosis or management of eosinophil peroxidase deficiency:  - Genetic Testing Registry: Eosinophil peroxidase deficiency  - Tulane University Eosinophilic Disorder Center   These resources from MedlinePlus offer information about the diagnosis and management of various health conditions:  - Diagnostic Tests  - Drug Therapy  - Surgery and Rehabilitation  - Genetic Counseling   - Palliative Care
Friedreich ataxia is a genetic condition that affects the nervous system and causes movement problems. People with this condition develop impaired muscle coordination (ataxia) that worsens over time. Other features of this condition include the gradual loss of strength and sensation in the arms and legs, muscle stiffness (spasticity), and impaired speech. Individuals with Friedreich ataxia often have a form of heart disease called hypertrophic cardiomyopathy that enlarges and weakens the heart muscle. Some affected individuals develop diabetes, impaired vision, hearing loss, or an abnormal curvature of the spine (scoliosis).  Most people with Friedreich ataxia begin to experience the signs and symptoms of the disorder around puberty. Poor balance when walking and slurred speech are often the first noticeable features. Affected individuals typically require the use of a wheelchair about 10 years after signs and symptoms appear.  About 25 percent of people with Friedreich ataxia have an atypical form that begins after age 25. Affected individuals who develop Friedreich ataxia between ages 26 and 39 are considered to have late-onset Friedreich ataxia (LOFA). When the signs and symptoms begin after age 40 the condition is called very late-onset Friedreich ataxia (VLOFA). LOFA and VLOFA usually progress more slowly than typical Friedreich ataxia.
Mutations in the FXN gene cause Friedreich ataxia. This gene provides instructions for making a protein called frataxin. Although its role is not fully understood, frataxin appears to be important for the normal function of mitochondria, the energy-producing centers within cells. One region of the FXN gene contains a segment of DNA known as a GAA trinucleotide repeat. This segment is made up of a series of three DNA building blocks (one guanine and two adenines) that appear multiple times in a row. Normally, this segment is repeated 5 to 33 times within the FXN gene.  In people with Friedreich ataxia, the GAA segment is repeated 66 to more than 1,000 times. The length of the GAA trinucleotide repeat appears to be related to the age at which the symptoms of Friedreich ataxia appear. People with GAA segments repeated fewer than 300 times tend to have a later appearance of symptoms (after age 25) than those with larger GAA trinucleotide repeats. The abnormally long GAA trinucleotide repeat disrupts the production of frataxin, which severely reduces the amount of this protein in cells. Certain nerve and muscle cells cannot function properly with a shortage of frataxin, leading to the characteristic signs and symptoms of Friedreich ataxia.
These resources address the diagnosis or management of Friedreich ataxia:  - Friedreich's Ataxia Research Alliance: Clinical Care Guidelines  - Gene Review: Gene Review: Friedreich Ataxia  - Genetic Testing Registry: Friedreich ataxia 1  - MedlinePlus Encyclopedia: Friedreich's Ataxia  - MedlinePlus Encyclopedia: Hypertrophic Cardiomyopathy  - National Institute of Neurological Disorders and Stroke: Friedreich's Ataxia Fact Sheet   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
Meesmann corneal dystrophy is an eye disease that affects the cornea, which is the clear front covering of the eye. This condition is characterized by the formation of tiny round cysts in the outermost layer of the cornea, called the corneal epithelium. This part of the cornea acts as a barrier to help prevent foreign materials, such as dust and bacteria, from entering the eye.  In people with Meesmann corneal dystrophy, cysts can appear as early as the first year of life. They usually affect both eyes and increase in number over time. The cysts usually do not cause any symptoms until late adolescence or adulthood, when they start to break open (rupture) on the surface of the cornea and cause irritation. The resulting symptoms typically include increased sensitivity to light (photophobia), twitching of the eyelids (blepharospasm), increased tear production, the sensation of having a foreign object in the eye, and an inability to tolerate wearing contact lenses. Some affected individuals also have temporary episodes of blurred vision.
Meesmann corneal dystrophy can result from mutations in either the KRT12 gene or the KRT3 gene. These genes provide instructions for making proteins called keratin 12 and keratin 3, which are found in the corneal epithelium. The two proteins interact to form the structural framework of this layer of the cornea. Mutations in either the KRT12 or KRT3 gene weaken this framework, causing the corneal epithelium to become fragile and to develop the cysts that characterize the disorder. The cysts likely contain clumps of abnormal keratin proteins and other cellular debris. When the cysts rupture, they cause eye irritation and the other symptoms of Meesmann corneal dystrophy.
These resources address the diagnosis or management of Meesmann corneal dystrophy:  - Genetic Testing Registry: Meesman's corneal dystrophy  - Merck Manual Home Health Handbook: Tests for Eye Disorders: The Eye Examination   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
Factor X deficiency is a rare bleeding disorder that varies in severity among affected individuals. The signs and symptoms of this condition can begin at any age, although the most severe cases are apparent in childhood. Factor X deficiency commonly causes nosebleeds, easy bruising, bleeding under the skin, bleeding of the gums, blood in the urine (hematuria), and prolonged or excessive bleeding following surgery or trauma. Women with factor X deficiency can have heavy or prolonged menstrual bleeding (menorrhagia) or excessive bleeding in childbirth, and may be at increased risk of pregnancy loss (miscarriage). Bleeding into joint spaces (hemarthrosis) occasionally occurs. Severely affected individuals have an increased risk of bleeding inside the skull (intracranial hemorrhage), in the lungs (pulmonary hemorrhage), or in the gastrointestinal tract, which can be life-threatening.
The inherited form of factor X deficiency, known as congenital factor X deficiency, is caused by mutations in the F10 gene, which provides instructions for making a protein called coagulation factor X. This protein plays a critical role in the coagulation system, which is a series of chemical reactions that forms blood clots in response to injury. Some F10 gene mutations that cause factor X deficiency reduce the amount of coagulation factor X in the bloodstream, resulting in a form of the disorder called type I. Other F10 gene mutations result in the production of a coagulation factor X protein with impaired function, leading to type II factor X deficiency. Reduced quantity or function of coagulation factor X prevents blood from clotting normally, causing episodes of abnormal bleeding that can be severe.  A non-inherited form of the disorder, called acquired factor X deficiency, is more common than the congenital form. Acquired factor X deficiency can be caused by other disorders such as severe liver disease or systemic amyloidosis, a condition involving the accumulation of abnormal proteins called amyloids. Acquired factor X deficiency can also be caused by certain drugs such as medicines that prevent clotting, or by a deficiency of vitamin K.
When this condition is caused by mutations in the F10 gene, it 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.  Acquired factor X deficiency is not inherited, and generally occurs in individuals with no history of the disorder in their family.
Senior-Lken syndrome is a rare disorder characterized by the combination of two specific features: a kidney condition called nephronophthisis and an eye condition known as Leber congenital amaurosis.  Nephronophthisis causes fluid-filled cysts to develop in the kidneys beginning in childhood. These cysts impair kidney function, initially causing increased urine production (polyuria), excessive thirst (polydipsia), general weakness, and extreme tiredness (fatigue). Nephronophthisis leads to end-stage renal disease (ESRD) later in childhood or in adolescence. ESRD is a life-threatening failure of kidney function that occurs when the kidneys are no longer able to filter fluids and waste products from the body effectively.  Leber congenital amaurosis primarily affects the retina, which is the specialized tissue at the back of the eye that detects light and color. This condition causes vision problems, including an increased sensitivity to light (photophobia), involuntary movements of the eyes (nystagmus), and extreme farsightedness (hyperopia). Some people with Senior-Lken syndrome develop the signs of Leber congenital amaurosis within the first few years of life, while others do not develop vision problems until later in childhood.
Senior-Lken syndrome can be caused by mutations in one of at least five genes. The proteins produced from these genes are known or suspected to play roles in cell structures called cilia. Cilia are microscopic, finger-like projections that stick out from the surface of cells; they are involved in signaling pathways that transmit information between cells. Cilia are important for the structure and function of many types of cells, including certain cells in the kidneys. They are also necessary for the perception of sensory input (such as vision, hearing, and smell).  Mutations in the genes associated with Senior-Lken syndrome likely lead to problems with the structure and function of cilia. Defects in these cell structures probably disrupt important chemical signaling pathways within cells. Although researchers believe that defective cilia are responsible for the features of this disorder, it remains unclear how they lead specifically to nephronophthisis and Leber congenital amaurosis.  Some people with Senior-Lken syndrome do not have identified mutations in one of the five genes known to be associated with the condition. In these cases, the genetic cause of the disorder is unknown.
These resources address the diagnosis or management of Senior-Lken syndrome:  - Genetic Testing Registry: Senior-Loken syndrome 1  - Genetic Testing Registry: Senior-Loken syndrome 3  - Genetic Testing Registry: Senior-Loken syndrome 4  - Genetic Testing Registry: Senior-Loken syndrome 5  - Genetic Testing Registry: Senior-Loken syndrome 6  - Genetic Testing Registry: Senior-Loken syndrome 7   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