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Mendelian Trait
Mendelian traits in humans are human traits that are substantially influenced by Mendelian inheritance. Most – if not all – Mendelian traits are also influenced by other genes, the environment, immune responses, and chance. Therefore no trait is purely Mendelian, but many traits are almost entirely Mendelian, including canonical examples, such as those listed below. Purely Mendelian traits are a minority of all traits, since most phenotypic traits exhibit incomplete dominance, codominance, and contributions from many genes. If a trait is genetically influenced, but not well characterized by Mendelian inheritance, it is non-Mendelian. Examples * Albinism (recessive) * Achondroplasia * Alkaptonuria * Ataxia telangiectasia * Brachydactyly (shortness of fingers and toes) * Cataracts * Colour blindness ( monochromatism, dichromatism, anomalous trichromatism, tritanopia, deuteranopia, protanopia) * Duchenne muscular dystrophy * Ectrodactyly * Ehlers–Danlos syndrome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autosomal Dominant - En
An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosomes is collectively known as atDNA or auDNA. For example, humans have a diploid genome that usually contains 22 pairs of autosomes and one allosome pair (46 chromosomes total). The autosome pairs are labeled with numbers (1–22 in humans) roughly in order of their sizes in base pairs, while allosomes are labelled with their letters. By contrast, the allosome pair consists of two X chromosomes in females or one X and one Y chromosome in males. Unusual combinations XYY, XXY, XXX, XXXX, XXXXX or XXYY, among other irregular combinations, are known to occur and usually cause developmental abnormalities. Autosomes still contain sexual determination genes even though they are not sex chromosomes. For example, the SRY gene on the Y chromosom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colour Blindness
Color blindness, color vision deficiency (CVD) or color deficiency is the decreased ability to see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color perception. Color blindness is usually a sex-linked inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic condition called congenital red–green color blindness (including protan and deutan types), which affects ''up to'' 1 in 12 males (8%) and 1 in 200 females (0.5%). The condition is more prevalent in males, because the opsin genes responsible are located on the X chromosome. Rarer genetic conditions causing color blindness include congenital blue–yellow color blindness (tritan type), blue cone monochromacy, and achromatopsia. Color blindness can also result from physical or chemical damage to the eye, the optic nerve, pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hereditary Nonpolyposis Colorectal Cancer
Hereditary nonpolyposis colorectal cancer (HNPCC) is a hereditary predisposition to colon cancer. HNPCC includes (and was once synonymous with) Lynch syndrome, an autosomal dominant genetic condition that is associated with a high risk of colon cancer, endometrial cancer (second most common), ovary, stomach, small intestine, hepatobiliary tract, upper urinary tract, brain, and skin. The increased risk for these cancers is due to inherited genetic mutations that impair DNA mismatch repair. It is a type of cancer syndrome. Other HNPCC conditions include Lynch-like syndrome, polymerase proofreading-associated polyposis and familial colorectal cancer type X. Signs and symptoms Risk of cancer ''Lifetime risk and mean age at diagnosis for Lynch syndrome–associated cancers'' In addition to the types of cancer found in the chart above, it is understood that Lynch syndrome also contributes to an increased risk of small bowel cancer, pancreatic cancer, ureter/renal pelvis cancer, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hereditary Breast–ovarian Cancer Syndrome
Hereditary breast–ovarian cancer syndromes (HBOC) are cancer syndromes that produce higher than normal levels of breast cancer, ovarian cancer and additional cancers in genetically related families (either one individual had both, or several individuals in the pedigree had one or the other disease). It accounts for 90% of the hereditary cancers. The hereditary factors may be proven or suspected to cause the pattern of breast and ovarian cancer occurrences in the family. The name HBOC may be misleading because it implies that this genetic susceptibility to cancer is mainly in women. In reality, both sexes have the same rates of gene mutations and HBOC can predispose to other cancers including prostate cancer and pancreatic cancer. For this reason, the term "King syndrome" has recently come into use. The new name references Mary-Claire King who identified the genes ''BRCA1'' and ''BRCA2''. Most hereditary breast-ovarian cancer syndromes are inherited in an autosomal dominant patt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haemophilia
Haemophilia (British English), or hemophilia (American English) (), is a mostly inherited genetic disorder that impairs the body's ability to make blood clots, a process needed to stop bleeding. This results in people bleeding for a longer time after an injury, easy bruising, and an increased risk of bleeding inside joints or the brain. Those with a mild case of the disease may have symptoms only after an accident or during surgery. Bleeding into a joint can result in permanent damage while bleeding in the brain can result in long term headaches, seizures, or an altered level of consciousness. There are two main types of haemophilia: haemophilia A, which occurs due to low amounts of clotting factor VIII, and haemophilia B, which occurs due to low levels of clotting factor IX. They are typically inherited from one's parents through an X chromosome carrying a nonfunctional gene. Most commonly found in men, haemophilia can affect women too, though very rarely. A woman wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gaucher's Disease
Gaucher's disease or Gaucher disease () (GD) is a genetic disorder in which glucocerebroside (a sphingolipid, also known as glucosylceramide) accumulates in cells and certain organs. The disorder is characterized by bruising, fatigue, anemia, low blood platelet count and enlargement of the liver and spleen, and is caused by a hereditary deficiency of the enzyme glucocerebrosidase (also known as glucosylceramidase), which acts on glucocerebroside. When the enzyme is defective, glucocerebroside accumulates, particularly in white blood cells and especially in macrophages ( mononuclear leukocytes, which is often a target for intracellular parasites). Glucocerebroside can collect in the spleen, liver, kidneys, lungs, brain, and bone marrow. Manifestations may include enlarged spleen and liver, liver malfunction, skeletal disorders or bone lesions that may be painful, severe neurological complications, swelling of lymph nodes and (occasionally) adjacent joints, distended abdomen, a b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galactosemia
Galactosemia (British galactosaemia, from Greek γαλακτόζη + αίμα, meaning galactose + blood, accumulation of galactose in blood) is a rare genetics, genetic Metabolism, metabolic Disease, disorder that affects an individual's ability to metabolize the sugar galactose properly. Galactosemia follows an autosomal recessive mode of inheritance that confers a deficiency in an enzyme responsible for adequate galactose degradation. Friedrich Goppert (1870–1927), a German physician, first described the disease in 1917, with its cause as a defect in galactose metabolism being identified by a group led by Herman Kalckar in 1956. Galactosemia was the second disorder found to be detectable through newborn screening methods by Robert Guthrie. Its incidence is about 1 per 60,000 births for people of European ancestry. In other populations the incidence rate differs. Galactosemia is about one hundred times more common (1:480 births) in the Irish Traveller population. Symptoms and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fabry Disease
Fabry disease, also known as Anderson–Fabry disease, is a rare genetic disease that can affect many parts of the body, including the kidneys, heart, brain, and skin. Fabry disease is one of a group of conditions known as lysosomal storage diseases. The genetic mutation that causes Fabry disease interferes with the function of an enzyme that processes biomolecules known as sphingolipids, leading to these substances building up in the walls of blood vessels and other organs. It is inherited in an X-linked manner. Fabry disease is sometimes diagnosed using a blood test that measures the activity of the affected enzyme called alpha-galactosidase, but genetic testing is also sometimes used, particularly in females. The treatment for Fabry disease varies depending on the organs affected by the condition, and the underlying cause can be addressed by replacing the enzyme that is lacking. The first descriptions of the condition were made simultaneously by dermatologist Johannes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ehlers–Danlos Syndrome
Ehlers–Danlos syndromes (EDS) is a group of 14 genetic connective-tissue disorders. Symptoms often include loose joints, joint pain, stretchy velvety skin, and abnormal scar formation. These may be noticed at birth or in early childhood. Complications may include aortic dissection, joint dislocations, scoliosis, chronic pain, or early osteoarthritis. The existing classification was last updated in 2017, when a number of rarer forms of EDS were added. EDS occurs due to mutations in one or more particular genes—there are 19 genes that can contribute to the condition. The specific gene affected determines the type of EDS, though the genetic causes of hypermobile Ehlers–Danlos syndrome are still unknown. Some cases result from a new variation occurring during early development, while others are inherited in an autosomal dominant or recessive manner. Typically, these variations result in defects in the structure or processing of the protein collagen or tenascin. Diagnos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ectrodactyly
Ectrodactyly, split hand, or cleft hand () involves the deficiency or absence of one or more central Digit (anatomy), digits of the hand or foot and is also known as split hand/split foot malformation (SHFM). The hands and feet of people with ectrodactyly (ectrodactyls) are often described as "claw-like" and may include only the thumb and one finger (usually either the little finger, ring finger, or a syndactyly of the two) with similar abnormalities of the feet. It is a substantial rare form of a congenital disorder in which the development of the hand is disturbed. It is a type I failure of formation – longitudinal arrest. The central ray of the hand is affected and usually appears without proximal deficiencies of nerves, vessels, tendons, muscles and bones in contrast to the radial and ulnar deficiencies. The cleft hand appears as a V-shaped cleft situated in the centre of the hand. The digits at the borders of the cleft might be syndactilyzed, and one or more digits can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a severe type of muscular dystrophy predominantly affecting boys. The onset of muscle weakness typically begins around age four, with rapid progression. Initially, muscle loss occurs in the thighs and pelvis, extending to the arms, which can lead to difficulties in standing up. By the age of 12, most individuals with Duchenne muscular dystrophy are unable to walk. Affected muscles may appear larger due to an increase in fat content, and scoliosis is common. Some individuals may experience intellectual disability, and females carrying a single copy of the mutated gene may show mild symptoms. Duchenne muscular dystrophy is caused by mutations or deletions in any of the 79 exons encoding the large dystrophin protein, which is essential for maintaining the muscle fibers' cell membrane integrity. The disorder follows an X-linked recessive inheritance pattern, with approximately two-thirds of cases inherited from the mother and one-third res ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Color Blindness
Color blindness, color vision deficiency (CVD) or color deficiency is the decreased ability to color vision, see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color perception. Color blindness is usually a Sex linkage, sex-linked Heredity, inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic condition called congenital red–green color blindness (including protan and deutan types), which affects ''up to'' 1 in 12 males (8%) and 1 in 200 females (0.5%). The condition is more prevalent in males, because the opsin genes responsible are located on the X chromosome. Rarer genetic conditions causing color blindness include congenital blue–yellow color blindness (tritan type), blue cone monochromacy, and achromatopsia. Color blindness can also result from physical or chemical dam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
