Genetic disorder

A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosome abnormality. Although polygenic disorders are the most common, the term is mostly used when discussing disorders with a single genetic cause, either in a gene or chromosome. The mutation responsible can occur spontaneously before embryonic development (a de novo mutation), or it can be inherited from two parents who are carriers of a faulty gene (autosomal recessive inheritance) or from a parent with the disorder (autosomal dominant inheritance). When the genetic disorder is inherited from one or both parents, it is also classified as a hereditary disease. Some disorders are caused by a mutation on the X chromosome and have X-linked inheritance. Very few disorders are inherited on the Y chromosome or mitochondrial DNA (due to their size). There are well over 6,000 known genetic disorders, and new genetic disorders are constantly being described in medical literature. More than 600 genetic disorders are treatable. Approximately 1 person in every 50 people is affected by a known single-gene disorder, while 1 in 263 is affected by a chromosomal disorder. About 65% of people have some kind of health problem as a result of congenital genetic mutations. Due to the significantly large number of genetic disorders, around 4.76% of people are affected by a genetic disorder classified as "rare" (usually defined as affecting fewer than 1 in 2,000 people). Most genetic disorders are rare in themselves. Genetic disorders are present before birth, and some genetic disorders produce birth defects, but birth defects can also be developmental rather than hereditary. The opposite of a hereditary disease is an acquired disease. Most cancers, although they involve genetic mutations...