bowang0911/MedQuAD huggingface dataset:
Meckel syndrome can be caused by mutations in one of at least eight 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 and are involved in signaling pathways that transmit information between cells. Cilia are important for the structure and function of many types of cells, including brain cells and certain cells in the kidneys and liver.  Mutations in the genes associated with Meckel syndrome lead to problems with the structure and function of cilia. Defects in these cell structures probably disrupt important chemical signaling pathways during early development. Although researchers believe that defective cilia are responsible for most of the features of this disorder, it remains unclear how they lead to specific developmental abnormalities of the brain, kidneys, and other parts of the body.  Mutations in the eight genes known to be associated with Meckel syndrome account for about 75 percent of all cases of the condition. In the remaining cases, the genetic cause is unknown. Mutations in several other genes have been identified in people with features similar to those of Meckel syndrome, although it is unclear whether these individuals actually have Meckel syndrome or a related disorder (often described as a "Meckel-like phenotype").
These resources address the diagnosis or management of Meckel syndrome:  - Genetic Testing Registry: Meckel syndrome type 1  - Genetic Testing Registry: Meckel syndrome type 2  - Genetic Testing Registry: Meckel syndrome type 3  - Genetic Testing Registry: Meckel syndrome type 4  - Genetic Testing Registry: Meckel syndrome type 5  - Genetic Testing Registry: Meckel syndrome type 6  - Genetic Testing Registry: Meckel syndrome type 7  - Genetic Testing Registry: Meckel syndrome type 8  - Genetic Testing Registry: Meckel syndrome, type 10  - Genetic Testing Registry: Meckel syndrome, type 9   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
The risk of developing celiac disease is increased by certain variants of the HLA-DQA1 and HLA-DQB1 genes. These genes provide instructions for making proteins that play a critical role in the immune system. The HLA-DQA1 and HLA-DQB1 genes belong to a family of genes called the human leukocyte antigen (HLA) complex. The HLA complex helps the immune system distinguish the body's own proteins from proteins made by foreign invaders such as viruses and bacteria.  The proteins produced from the HLA-DQA1 and HLA-DQB1 genes attach (bind) to each other to form a functional protein complex called an antigen-binding DQ heterodimer. This complex, which is present on the surface of certain immune system cells, attaches to protein fragments (peptides) outside the cell. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it triggers a response to attack the invading viruses or bacteria.  Celiac disease is associated with an inappropriate immune response to a segment of the gluten protein called gliadin. This inappropriate activation of the immune system causes inflammation that damages the body's organs and tissues and leads to the signs and symptoms of celiac disease.  Almost all people with celiac disease have specific variants of the HLA-DQA1 and HLA-DQB1 genes, which seem to increase the risk of an inappropriate immune response to gliadin. However, these variants are also found in 30 percent of the general population, and only 3 percent of individuals with the gene variants develop celiac disease.  It appears likely that other contributors, such as environmental factors and changes in other genes, also influence the development of this complex disorder.
These resources address the diagnosis or management of celiac disease:  - Beth Israel Deaconess: Celiac Center  - Columbia University Celiac Disease Center  - Gene Review: Gene Review: Celiac Disease  - Genetic Testing Registry: Celiac disease  - Massachusetts General Hospital Center for Celiac Research and Treatment  - MedlinePlus Encyclopedia: Celiac Disease Nutritional Considerations  - North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition: Gluten-Free Diet Guide  - University of Chicago Celiac Disease 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
Lesch-Nyhan syndrome is a condition that occurs almost exclusively in males. It is characterized by neurological and behavioral abnormalities and the overproduction of uric acid. Uric acid is a waste product of normal chemical processes and is found in blood and urine. Excess uric acid can be released from the blood and build up under the skin and cause gouty arthritis (arthritis caused by an accumulation of uric acid in the joints). Uric acid accumulation can also cause kidney and bladder stones.  The nervous system and behavioral disturbances experienced by people with Lesch-Nyhan syndrome include abnormal involuntary muscle movements, such as tensing of various muscles (dystonia), jerking movements (chorea), and flailing of the limbs (ballismus). People with Lesch-Nyhan syndrome usually cannot walk, require assistance sitting, and generally use a wheelchair. Self-injury (including biting and head banging) is the most common and distinctive behavioral problem in individuals with Lesch-Nyhan syndrome.
Mutations in the HPRT1 gene cause Lesch-Nyhan syndrome. The HPRT1 gene provides instructions for making an enzyme called hypoxanthine phosphoribosyltransferase 1. This enzyme is responsible for recycling purines, a type of building block of DNA and its chemical cousin RNA. Recycling purines ensures that cells have a plentiful supply of building blocks for the production of DNA and RNA.  HPRT1 gene mutations that cause Lesch-Nyhan syndrome result in a severe shortage (deficiency) or complete absence of hypoxanthine phosphoribosyltransferase 1. When this enzyme is lacking, purines are broken down but not recycled, producing abnormally high levels of uric acid. For unknown reasons, a deficiency of hypoxanthine phosphoribosyltransferase 1 is associated with low levels of a chemical messenger in the brain called dopamine. Dopamine transmits messages that help the brain control physical movement and emotional behavior, and its shortage may play a role in the movement problems and other features of this disorder. However, it is unclear how a shortage of hypoxanthine phosphoribosyltransferase 1 causes the neurological and behavioral problems characteristic of Lesch-Nyhan syndrome.  Some people with HPRT1 gene mutations produce some functional enzyme. These individuals are said to have Lesch-Nyhan variant. The signs and symptoms of Lesch-Nyhan variant are often milder than those of Lesch-Nyhan syndrome and do not include self-injury.
These resources address the diagnosis or management of Lesch-Nyhan syndrome:  - Gene Review: Gene Review: Lesch-Nyhan Syndrome  - Genetic Testing Registry: Lesch-Nyhan syndrome  - MedlinePlus Encyclopedia: Lesch-Nyhan Syndrome  - MedlinePlus Encyclopedia: Uric Acid Crystals   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
Dopa-responsive dystonia is a disorder that involves involuntary muscle contractions, tremors, and other uncontrolled movements (dystonia). The features of this condition range from mild to severe. This form of dystonia is called dopa-responsive dystonia because the signs and symptoms typically improve with sustained use of a medication known as L-Dopa.  Signs and symptoms of dopa-responsive dystonia usually appear during childhood, most commonly around age 6. The first signs of the condition are typically the development of inward- and upward-turning feet (clubfeet) and dystonia in the lower limbs. The dystonia spreads to the upper limbs over time; beginning in adolescence, the whole body is typically involved. Affected individuals may have unusual limb positioning and a lack of coordination when walking or running. Some people with this condition have sleep problems or episodes of depression more frequently than would normally be expected.  Over time, affected individuals often develop a group of movement abnormalities called parkinsonism. These abnormalities include unusually slow movement (bradykinesia), muscle rigidity, tremors, and an inability to hold the body upright and balanced (postural instability).  The movement difficulties associated with dopa-responsive dystonia usually worsen with age but stabilize around age 30. A characteristic feature of dopa-responsive dystonia is worsening of movement problems later in the day and an improvement of symptoms in the morning, after sleep (diurnal fluctuation).  Rarely, the movement problems associated with dopa-responsive dystonia do not appear until adulthood. In these adult-onset cases, parkinsonism usually develops before dystonia, and movement problems are slow to worsen and do not show diurnal fluctuations.
Mutations in the GCH1 gene are the most common cause of dopa-responsive dystonia. Less often, mutations in the TH or SPR gene cause this condition.  The GCH1 gene provides instructions for making an enzyme called GTP cyclohydrolase. This enzyme is involved in the first of three steps in the production of a molecule called tetrahydrobiopterin (BH4). The SPR gene, which provides instructions for making the sepiapterin reductase enzyme, is involved in the last step of tetrahydrobiopterin production. Tetrahydrobiopterin helps process several protein building blocks (amino acids), and is involved in the production of chemicals called neurotransmitters, which transmit signals between nerve cells in the brain. Specifically, tetrahydrobiopterin is involved in the production of two neurotransmitters called dopamine and serotonin. Among their many functions, dopamine transmits signals within the brain to produce smooth physical movements, and serotonin regulates mood, emotion, sleep, and appetite.  The protein produced from the TH gene is also involved in dopamine production. The TH gene provides instructions for making the enzyme tyrosine hydroxylase, which helps convert the amino acid tyrosine to dopamine.  Mutations in the GCH1 or SPR gene impair the production of tetrahydrobiopterin, which leads to a decrease in the amount of available dopamine. TH gene mutations result in the production of a tyrosine hydroxylase enzyme with reduced function, which leads to a decrease in dopamine production. A reduction in the amount of dopamine interferes with the brain's ability to produce smooth physical movements, resulting in the dystonia, tremor, and other movement problems associated with dopa-responsive dystonia. Sleep and mood disorders also occur in some individuals with GCH1 or SPR gene mutations; these disorders likely result from a disruption in the production of serotonin. Problems with sleep and episodes of depression are not seen in people with dopa-responsive dystonia caused by TH gene mutations, which is sometimes referred to as Segawa syndrome.  Some people with dopa-responsive dystonia do not have an identified mutation in the GCH1, TH, or SPR gene. The cause of the condition in these individuals is unknown.
When dopa-responsive dystonia is caused by mutations in the GCH1 gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.  Some people who inherit the altered GCH1 gene never develop features of dopa-responsive dystonia. (This situation is known as reduced penetrance.) It is unclear why some people with a mutated gene develop the disease and other people with a mutated gene do not. For unknown reasons, dopa-responsive dystonia caused by mutations in the GCH1 gene affects females two to four times more often than males.  When TH gene mutations are responsible for causing dopa-responsive dystonia, 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.  When dopa-responsive dystonia is caused by mutations in the SPR gene, it can have either an autosomal recessive or, less commonly, an autosomal dominant pattern of inheritance.
These resources address the diagnosis or management of dopa-responsive dystonia:  - Dartmouth-Hitchcock Children's Hospital at Dartmouth  - Gene Review: Gene Review: Dystonia Overview  - Gene Review: Gene Review: GTP Cyclohydrolase 1-Deficient Dopa-Responsive Dystonia  - Genetic Testing Registry: Dystonia 5, Dopa-responsive type  - Genetic Testing Registry: Segawa syndrome, autosomal recessive  - Genetic Testing Registry: Sepiapterin reductase deficiency   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
Cutis laxa is a disorder of connective tissue, which is the tissue that forms the body's supportive framework. Connective tissue provides structure and strength to the muscles, joints, organs, and skin.  The term "cutis laxa" is Latin for loose or lax skin, and this condition is characterized by skin that is sagging and not stretchy (inelastic). The skin often hangs in loose folds, causing the face and other parts of the body to have a droopy appearance. Extremely wrinkled skin may be particularly noticeable on the neck and in the armpits and groin.  Cutis laxa can also affect connective tissue in other parts of the body, including the heart, blood vessels, joints, intestines, and lungs. The disorder can cause heart problems and abnormal narrowing, bulging, or tearing of critical arteries. Affected individuals may have soft out-pouchings in the lower abdomen (inguinal hernia) or around the belly button (umbilical hernia). Pouches called diverticula can also develop in the walls of certain organs, such as the bladder and intestines. During childhood, some people with cutis laxa develop a lung disease called emphysema, which can make it difficult to breathe. Depending on which organs and tissues are affected, the signs and symptoms of cutis laxa can range from mild to life-threatening.  Researchers have described several different forms of cutis laxa. The forms are often distinguished by their pattern of inheritance: autosomal dominant, autosomal recessive, or X-linked. In general, the autosomal recessive forms of cutis laxa tend to be more severe than the autosomal dominant form. In addition to the features described above, some people with autosomal recessive cutis laxa have delayed development, intellectual disability, seizures, and problems with movement that can worsen over time.  The X-linked form of cutis laxa is often called occipital horn syndrome. This form of the disorder is considered a mild type of Menkes syndrome, which is a condition that affects copper levels in the body. In addition to sagging and inelastic skin, occipital horn syndrome is characterized by wedge-shaped calcium deposits in a bone at the base of the skull (the occipital bone), coarse hair, and loose joints.
Cutis laxa can be caused by mutations in the ATP6V0A2, ATP7A, EFEMP2, ELN, or FBLN5 gene. Most of these genes are involved in the formation and function of elastic fibers, which are slender bundles of proteins that provide strength and flexibility to connective tissue throughout the body. Elastic fibers allow the skin to stretch, the lungs to expand and contract, and arteries to handle blood flowing through them at high pressure.  The major component of elastic fibers, a protein called elastin, is produced from the ELN gene. Other proteins that appear to have critical roles in the assembly of elastic fibers are produced from the EFEMP2, FBLN5, and ATP6V0A2 genes. Mutations in any of these genes disrupt the formation, assembly, or function of elastic fibers. A shortage of these fibers weakens connective tissue in the skin, arteries, lungs, and other organs. These defects in connective tissue underlie the major features of cutis laxa.  Occipital horn syndrome is caused by mutations in the ATP7A gene. This gene provides instructions for making a protein that is important for regulating copper levels in the body. Mutations in the ATP7A gene result in poor distribution of copper to the body's cells. A reduced supply of copper can decrease the activity of numerous copper-containing enzymes that are necessary for the structure and function of bone, skin, hair, blood vessels, and the nervous system. The signs and symptoms of occipital horn syndrome are caused by the reduced activity of these copper-containing enzymes.  Mutations in the genes described above account for only a small percentage of all cases of cutis laxa. Researchers suspect that mutations in other genes, which have not been identified, can also be responsible for the condition.  Rare cases of cutis laxa are acquired, which means they are probably not caused by inherited gene mutations. Acquired cutis laxa appears later in life and is related to the destruction of normal elastic fibers. The causes of acquired cutis laxa are unclear, although it may occur as a side effect of treatment with medications that remove copper from the body (copper chelating drugs).
Cutis laxa can have an autosomal dominant, autosomal recessive, or X-linked recessive pattern of inheritance.  When cutis laxa is caused by ELN mutations, it has an autosomal dominant inheritance pattern. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder. Rarely, cases of cutis laxa resulting from FBLN5 mutations can also have an autosomal dominant pattern of inheritance.  Researchers have described at least two forms of autosomal recessive cutis laxa. Type I results from mutations in the EFEMP2 or FBLN5 gene, while type II is caused by mutations in the ATP6V02 gene. Autosomal recessive inheritance means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.  Occipital horn syndrome has an X-linked recessive pattern of inheritance. It results from mutations in the ATP7A gene, which is located on the X chromosome. The X chromosome is one of the two sex chromosomes. In males (who have only one X chromosome), one altered copy of the gene in each cell is sufficient to cause the condition. In females (who have two X chromosomes), a mutation would have to occur in both copies of the gene to cause the disorder. Because it is unlikely that females will have two altered copies of this gene, males are affected by X-linked recessive disorders much more frequently than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
These resources address the diagnosis or management of cutis laxa:  - Gene Review: Gene Review: ATP6V0A2-Related Cutis Laxa  - Gene Review: Gene Review: ATP7A-Related Copper Transport Disorders  - Gene Review: Gene Review: EFEMP2-Related Cutis Laxa  - Gene Review: Gene Review: FBLN5-Related Cutis Laxa  - Genetic Testing Registry: Autosomal recessive cutis laxa type IA  - Genetic Testing Registry: Cutis laxa with osteodystrophy  - Genetic Testing Registry: Cutis laxa, X-linked  - Genetic Testing Registry: Cutis laxa, autosomal dominant  - MedlinePlus Encyclopedia: Colon Diverticula (image)  - MedlinePlus Encyclopedia: Emphysema (image)  - MedlinePlus Encyclopedia: Hernia   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
Bjrnstad syndrome is a rare disorder characterized by abnormal hair and hearing problems. Affected individuals have a condition known as pili torti, which means "twisted hair," so named because the strands appear twisted when viewed under a microscope. The hair is brittle and breaks easily, leading to short hair that grows slowly. In Bjrnstad syndrome, pili torti usually affects only the hair on the head; eyebrows, eyelashes, and hair on other parts of the body are normal. The proportion of hairs affected and the severity of brittleness and breakage can vary. This hair abnormality commonly begins before the age of 2. It may become milder with age, particularly after puberty.  People with Bjrnstad syndrome also have hearing problems that become evident in early childhood. The hearing loss, which is caused by changes in the inner ear (sensorineural deafness), can range from mild to severe. Mildly affected individuals may be unable to hear sounds at certain frequencies, while severely affected individuals may not be able to hear at all.
Bjrnstad syndrome is caused by mutations in the BCS1L gene. The protein produced from this gene is found in cell structures called mitochondria, which convert the energy from food into a form that cells can use. In mitochondria, the BCS1L protein plays a role in oxidative phosphorylation, which is a multistep process through which cells derive much of their energy. The BCS1L protein is critical for the formation of a group of proteins known as complex III, which is one of several protein complexes involved in this process. As a byproduct of its action in oxidative phosphorylation, complex III produces reactive oxygen species, which are harmful molecules that can damage DNA and tissues.  BCS1L gene mutations involved in Bjrnstad syndrome alter the BCS1L protein and impair its ability to aid in complex III formation. The resulting decrease in complex III activity reduces oxidative phosphorylation. For unknown reasons, overall production of reactive oxygen species is increased, although production by complex III is reduced. Researchers believe that tissues in the inner ears and hair follicles are particularly sensitive to reactive oxygen species and are damaged by the abnormal amount of these molecules, leading to the characteristic features of Bjrnstad syndrome.
These resources address the diagnosis or management of Bjrnstad syndrome:  - Centers for Disease Control and Prevention: Hearing Loss in Children: Screening and Diagnosis  - Genetic Testing Registry: Pili torti-deafness 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