bowang0911/MedQuAD huggingface dataset:
Primary myelofibrosis is a condition characterized by the buildup of scar tissue (fibrosis) in the bone marrow, the tissue that produces blood cells. Because of the fibrosis, the bone marrow is unable to make enough normal blood cells. The shortage of blood cells causes many of the signs and symptoms of primary myelofibrosis.  Initially, most people with primary myelofibrosis have no signs or symptoms. Eventually, fibrosis can lead to a reduction in the number of red blood cells, white blood cells, and platelets. A shortage of red blood cells (anemia) often causes extreme tiredness (fatigue) or shortness of breath. A loss of white blood cells can lead to an increased number of infections, and a reduction of platelets can cause easy bleeding or bruising.  Because blood cell formation (hematopoiesis) in the bone marrow is disrupted, other organs such as the spleen or liver may begin to produce blood cells. This process, called extramedullary hematopoiesis, often leads to an enlarged spleen (splenomegaly) or an enlarged liver (hepatomegaly). People with splenomegaly may feel pain or fullness in the abdomen, especially below the ribs on the left side. Other common signs and symptoms of primary myelofibrosis include fever, night sweats, and bone pain.  Primary myelofibrosis is most commonly diagnosed in people aged 50 to 80 but can occur at any age.
Mutations in the JAK2, MPL, CALR, and TET2 genes are associated with most cases of primary myelofibrosis. The JAK2 and MPL genes provide instructions for making proteins that promote the growth and division (proliferation) of blood cells. The CALR gene provides instructions for making a protein with multiple functions, including ensuring the proper folding of newly formed proteins and maintaining the correct levels of stored calcium in cells. The TET2 gene provides instructions for making a protein whose function is unknown.  The proteins produced from the JAK2 and MPL genes are both part of a signaling pathway called the JAK/STAT pathway, which transmits chemical signals from outside the cell to the cell's nucleus. The protein produced from the MPL gene, called thrombopoietin receptor, turns on (activates) the pathway, and the JAK2 protein transmits signals after activation. Through the JAK/STAT pathway, these two proteins promote the proliferation of blood cells, particularly a type of blood cell known as a megakaryocyte.  Mutations in either the JAK2 gene or the MPL gene that are associated with primary myelofibrosis lead to overactivation of the JAK/STAT pathway. The abnormal activation of JAK/STAT signaling leads to overproduction of abnormal megakaryocytes, and these megakaryocytes stimulate another type of cell to release collagen. Collagen is a protein that normally provides structural support for the cells in the bone marrow. However, in primary myelofibrosis, the excess collagen forms scar tissue in the bone marrow.  Although mutations in the CALR gene and the TET2 gene are relatively common in primary myelofibrosis, it is unclear how these mutations are involved in the development of the condition.  Some people with primary myelofibrosis do not have a mutation in any of the known genes associated with this condition. Researchers are working to identify other genes that may be involved in the condition.
These resources address the diagnosis or management of primary myelofibrosis:  - Genetic Testing Registry: Myelofibrosis  - Merck Manual Professional Version: Primary Myelofibrosis  - Myeloproliferative Neoplasm (MPN) Research Foundation: Primary Myelofibrosis (PMF)   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
Piebaldism is a condition characterized by the absence of cells called melanocytes in certain areas of the skin and hair. Melanocytes produce the pigment melanin, which contributes to hair, eye, and skin color. The absence of melanocytes leads to patches of skin and hair that are lighter than normal. Approximately 90 percent of affected individuals have a white section of hair near their front hairline (a white forelock). The eyelashes, the eyebrows, and the skin under the forelock may also be unpigmented.  People with piebaldism usually have other unpigmented patches of skin, typically appearing symmetrically on both sides of the body. There may be spots or patches of pigmented skin within or around the borders of the unpigmented areas.  In most cases, the unpigmented areas are present at birth and do not increase in size or number. The unpigmented patches are at increased risk of sunburn and skin cancer related to excessive sun exposure. Some people with piebaldism are self-conscious about the appearance of the unpigmented patches, which may be more noticeable in darker-skinned people. Aside from these potential issues, this condition has no effect on the health of the affected individual.
Piebaldism can be caused by mutations in the KIT and SNAI2 genes. Piebaldism may also be a feature of other conditions, such as Waardenburg syndrome; these conditions have other genetic causes and additional signs and symptoms.  The KIT gene provides instructions for making a protein that is involved in signaling within cells. KIT protein signaling is important for the development of certain cell types, including melanocytes. The KIT gene mutations responsible for piebaldism lead to a nonfunctional KIT protein. The loss of KIT signaling is thought to disrupt the growth and division (proliferation) and movement (migration) of melanocytes during development, resulting in patches of skin that lack pigmentation.  The SNAI2 gene (often called SLUG) provides instructions for making a protein called snail 2. Research indicates that the snail 2 protein is required during embryonic growth for the development of cells called neural crest cells. Neural crest cells migrate from the developing spinal cord to specific regions in the embryo and give rise to many tissues and cell types, including melanocytes. The snail 2 protein probably plays a role in the formation and survival of melanocytes. SNAI2 gene mutations that cause piebaldism probably reduce the production of the snail 2 protein. Shortage of the snail 2 protein may disrupt the development of melanocytes in certain areas of the skin and hair, causing the patchy loss of pigment.  Piebaldism is sometimes mistaken for another condition called vitiligo, which also causes unpigmented patches of skin. People are not born with vitiligo, but acquire it later in life, and it is not caused by specific genetic mutations. For unknown reasons, in people with vitiligo the immune system appears to damage the melanocytes in the skin.
Laron syndrome is a rare form of short stature that results from the body's inability to use growth hormone, a substance produced by the brain's pituitary gland that helps promote growth. Affected individuals are close to normal size at birth, but they experience slow growth from early childhood that results in very short stature. If the condition is not treated, adult males typically reach a maximum height of about 4.5 feet; adult females may be just over 4 feet tall.  Other features of untreated Laron syndrome include reduced muscle strength and endurance, low blood sugar levels (hypoglycemia) in infancy, small genitals and delayed puberty, hair that is thin and fragile, and dental abnormalities. Many affected individuals have a distinctive facial appearance, including a protruding forehead, a sunken bridge of the nose (saddle nose), and a blue tint to the whites of the eyes (blue sclerae). Affected individuals have short limbs compared to the size of their torso, as well as small hands and feet. Adults with this condition tend to develop obesity. However, the signs and symptoms of Laron syndrome vary, even among affected members of the same family.  Studies suggest that people with Laron syndrome have a significantly reduced risk of cancer and type 2 diabetes. Affected individuals appear to develop these common diseases much less frequently than their unaffected relatives, despite having obesity (a risk factor for both cancer and type 2 diabetes). However, people with Laron syndrome do not seem to have an increased lifespan compared with their unaffected relatives.
Laron syndrome is caused by mutations in the GHR gene. This gene provides instructions for making a protein called the growth hormone receptor. The receptor is present on the outer membrane of cells throughout the body, particularly liver cells. As its name suggests, the growth hormone receptor attaches (binds) to growth hormone; the two proteins fit together like a key in a lock. When growth hormone is bound to its receptor, it triggers signaling that stimulates the growth and division of cells. This signaling also leads to the production, primarily by liver cells, of another important growth-promoting hormone called insulin-like growth factor I (IGF-I).  Growth hormone and IGF-I have a wide variety of effects on the growth and function of many parts of the body. For example, these hormones stimulate the growth and division of cells called chondrocytes, which play a critical role in producing new bone tissue. Growth hormone and IGF-I also influence metabolism, including how the body uses and stores carbohydrates, proteins, and fats from food.  Mutations in the GHR gene impair the receptor's ability to bind to growth hormone or to trigger signaling within cells. As a result, even when growth hormone is available, cells are unable to respond by producing IGF-I and stimulating growth and division. The cells' inability to react to growth hormone, which is described as growth hormone insensitivity, disrupts the normal growth and function of many different tissues. Short stature results when growth hormone cannot adequately stimulate the growth of bones. Changes in metabolism caused by insensitivity to growth hormone and the resulting shortage of IGF-I cause many of the other features of the condition, including obesity.  Researchers are working to determine how mutations in the GHR gene may protect people with Laron syndrome from developing cancer and type 2 diabetes. Studies suggest that insensitivity to growth hormone may help prevent the uncontrolled growth and division of cells that can lead to the development of cancerous tumors. Growth hormone insensitivity also appears to alter how the body responds to insulin, which is a hormone that regulates blood sugar levels. Resistance to the effects of insulin is a major risk factor for type 2 diabetes. People with Laron syndrome have the opposite situation, an increased sensitivity to insulin, which likely helps explain their reduced risk of this common disease.
Most cases of Laron syndrome are inherited in an autosomal recessive pattern, which means both copies of the GHR 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.  Much less commonly, the condition has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most of these cases, an affected person has one parent with the condition.
These resources address the diagnosis or management of Laron syndrome:  - Children's Hospital of Pittsburgh: Growth Hormone Treatment  - Cinncinati Children's Hospital Medical Center: Growth Hormone Therapy  - Genetic Testing Registry: Laron-type isolated somatotropin defect   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
Spastic paraplegia type 15 is part of a group of genetic disorders known as hereditary spastic paraplegias. These disorders are characterized by progressive muscle stiffness (spasticity) and the development of paralysis of the lower limbs (paraplegia). Spastic paraplegia type 15 is classified as a complex hereditary spastic paraplegia because it involves all four limbs as well as additional features, including abnormalities of the brain. In addition to the muscles and brain, spastic paraplegia type 15 affects the peripheral nervous system, which consists of nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound.  Spastic paraplegia type 15 usually becomes apparent in childhood or adolescence with the development of weak muscle tone (hypotonia), difficulty walking, or intellectual disability. In almost all affected individuals, the tissue connecting the left and right halves of the brain (corpus callosum) is abnormally thin and becomes thinner over time. Additionally, there is often a loss (atrophy) of nerve cells in several parts of the brain, including the cerebral cortex, which controls thinking and emotions, and the cerebellum, which coordinates movement.  People with this form of spastic paraplegia can have numbness, tingling, or pain in the arms and legs (sensory neuropathy); impairment of the nerves used for muscle movement (motor neuropathy); exaggerated reflexes (hyperreflexia) of the lower limbs; muscle wasting (amyotrophy); or reduced bladder control. Rarely, spastic paraplegia type 15 is associated with a group of movement abnormalities called parkinsonism, which includes tremors, rigidity, and unusually slow movement (bradykinesia). People with spastic paraplegia type 15 may have an eye condition called pigmentary maculopathy that often impairs vision. This condition results from the breakdown (degeneration) of tissue at the back of the eye called the macula, which is responsible for sharp central vision.  Most people with spastic paraplegia type 15 experience a decline in intellectual ability and an increase in muscle weakness and nerve abnormalities over time. As the condition progresses, many people require walking aids or wheelchair assistance in adulthood.
Mutations in the ZFYVE26 gene cause spastic paraplegia type 15. This gene provides instructions for making a protein called spastizin. This protein is important in a process called autophagy, in which worn-out cell parts and unneeded proteins are recycled within cells. Specifically, spastizin is involved in the formation and maturation of sacs called autophagosomes (or autophagic vacuoles) that transport unneeded materials to be broken down. Spastizin also plays a role in the process by which dividing cells separate from one another (cytokinesis).  Many ZFYVE26 gene mutations that cause spastic paraplegia type 15 result in a shortened spastizin protein that is quickly broken down. As a result, functional autophagosomes are not produced, autophagy cannot occur, and recycling of materials within cells is decreased. An inability to break down unneeded materials, and the subsequent accumulation of these materials in cells, leads to cell dysfunction and often cell death. The loss of cells in the brain and other parts of the body is responsible for many of the features of spastic paraplegia type 15.  It is unclear whether a lack of spastizin protein interferes with normal cytokinesis and whether impaired cell division contributes to the signs and symptoms of spastic paraplegia type 15.
These resources address the diagnosis or management of spastic paraplegia type 15:  - Gene Review: Gene Review: Hereditary Spastic Paraplegia Overview  - Spastic Paraplegia Foundation, Inc: Treatments and Therapies   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
Vitamin D-dependent rickets is a disorder of bone development that leads to softening and weakening of the bones (rickets). The condition is split into two major types: type 1 (VDDR1), which is also known as pseudovitamin D deficiency rickets or vitamin D 1-hydroxylase deficiency, and type 2 (VDDR2), also known as hereditary vitamin D-resistant rickets (HVDRR).  The signs and symptoms of this condition begin within months of birth, and most are the same for VDDR1 and VDDR2. The weak bones often cause bone pain and delayed growth and have a tendency to fracture. When affected children begin to walk, they may develop bowed legs because the bones are too weak to bear weight. Impaired bone development also results in widening of the areas near the ends of bones where new bone forms (metaphyses), especially in the knees, wrists, and ribs. Some people with vitamin D-dependent rickets have dental abnormalities such as thin tooth enamel and frequent cavities. Poor muscle tone (hypotonia) and muscle weakness are also common in this condition, and some affected individuals develop seizures.  In vitamin D-dependent rickets, there is an imbalance of certain substances in the blood. Both VDDR1 and VDDR2 are characterized by low levels of the minerals calcium (hypocalcemia) and phosphate (hypophosphatemia), which are essential for the normal formation of bones and teeth. Affected individuals also have high levels of a hormone involved in regulating calcium levels called parathyroid hormone (PTH), which leads to a condition called secondary hyperparathyroidism. The two forms of vitamin D-dependent rickets can be distinguished by blood levels of a hormone called calcitriol, which is the active form of vitamin D; individuals with VDDR1 have abnormally low levels of calcitriol and individuals with VDDR2 have abnormally high levels.  Hair loss (alopecia) can occur in VDDR2, although not everyone with this form of the condition has alopecia. Affected individuals can have sparse or patchy hair or no hair at all on their heads. Some affected individuals are missing body hair as well.
Rickets affects an estimated 1 in 200,000 children. The condition is most often caused by a lack of vitamin D in the diet or insufficient sun exposure rather than genetic mutations; genetic forms of rickets, including VDDR1 and VDDR2, are much less common. The prevalence of VDDR1 and VDDR2 is unknown. VDDR1 is more common in the French Canadian population than in other populations.
The two types of vitamin D-dependent rickets have different genetic causes: CYP27B1 gene mutations cause VDDR1, and VDR gene mutations cause VDDR2. Both genes are involved in the body's response to vitamin D, an important vitamin that can be can be acquired from foods in the diet or made by the body with the help of sunlight. Vitamin D helps maintain the proper balance of several minerals in the body, including calcium and phosphate. One of vitamin D's major roles is to control the absorption of calcium and phosphate from the intestines into the bloodstream.  The CYP27B1 gene provides instructions for making an enzyme called 1-alpha-hydroxylase (1-hydroxylase). This enzyme carries out the final reaction to convert vitamin D to its active form, calcitriol. Once converted, calcitriol attaches (binds) to a protein called vitamin D receptor (VDR), which is produced from the VDR gene. The resulting calcitriol-VDR complex then binds to particular regions of DNA and regulates the activity of vitamin D-responsive genes. By turning these genes on or off, VDR helps control the absorption of calcium and phosphate and other processes that regulate calcium levels in the body. VDR is also involved in hair growth through a process that does not require calcitriol binding.  Mutations in either of these genes prevent the body from responding to vitamin D. CYP27B1 gene mutations reduce or eliminate 1-hydroxylase activity, which means vitamin D is not converted to its active form. The absence of calcitriol means vitamin D-responsive genes are not turned on (activated). VDR gene mutations alter the vitamin D receptor so that it cannot regulate gene activity, regardless of the presence of calcitriol in the body; often the altered receptor cannot interact with calcitriol or with DNA.  Without activation of vitamin D-responsive genes, absorption of calcium and phosphate falls, leading to hypocalcemia and hypophosphatemia. The lack of calcium and phosphate slows the deposition of these minerals in developing bones (bone mineralization), which leads to soft, weak bones and other features of vitamin D-dependent rickets. Low levels of calcium stimulate production of PTH, resulting in secondary hyperparathyroidism; hypocalcemia can also cause muscle weakness and seizures in individuals with vitamin D-dependent rickets. Certain abnormalities in the VDR protein also impair hair growth, causing alopecia in some people with VDDR2.
These resources address the diagnosis or management of vitamin D-dependent rickets:  - Genetic Testing Registry: Vitamin D-dependent rickets, type 1  - Genetic Testing Registry: Vitamin D-dependent rickets, type 2  - Genetic Testing Registry: Vitamin d-dependent rickets, type 2b, with normal vitamin d receptor   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
1q21.1 microdeletion is a chromosomal change in which a small piece of chromosome 1 is deleted in each cell. The deletion occurs on the long (q) arm of the chromosome in a region designated q21.1. This chromosomal change increases the risk of delayed development, intellectual disability, physical abnormalities, and neurological and psychiatric problems. However, some people with a 1q21.1 microdeletion do not appear to have any associated features.  About 75 percent of all children with a 1q21.1 microdeletion have delayed development, particularly affecting the development of motor skills such as sitting, standing, and walking. The intellectual disability and learning problems associated with this genetic change are usually mild.  Distinctive facial features can also be associated with 1q21.1 microdeletions. The changes are usually subtle and can include a prominent forehead; a large, rounded nasal tip; a long space between the nose and upper lip (philtrum); and a high, arched roof of the mouth (palate). Other common signs and symptoms of 1q21.1 microdeletions include an unusually small head (microcephaly), short stature, and eye problems such as clouding of the lenses (cataracts). Less frequently, 1q21.1 microdeletions are associated with heart defects, abnormalities of the genitalia or urinary system, bone abnormalities (particularly in the hands and feet), and hearing loss.  Neurological problems that have been reported in people with a 1q21.1 microdeletion include seizures and weak muscle tone (hypotonia). Psychiatric or behavioral problems affect a small percentage of people with this genetic change. These include developmental conditions called autism spectrum disorders that affect communication and social interaction, attention deficit hyperactivity disorder (ADHD), and sleep disturbances. Studies suggest that deletions of genetic material from the 1q21.1 region may also be risk factors for schizophrenia.  Some people with a 1q21.1 microdeletion do not have any of the intellectual, physical, or psychiatric features described above. In these individuals, the microdeletion is often detected when they undergo genetic testing because they have a relative with the chromosomal change. It is unknown why 1q21.1 microdeletions cause cognitive and physical changes in some individuals but few or no health problems in others, even within the same family.