Acquired mutation: A genetic change that occurs in a single cell after the conception of an individual. That change is then passed along to all cells descended from that cell. Acquired mutations are involved in the development of cancer.
- Acrocentric chromosome
Acrocentric chromosome: A chromosome in which the centromere is located quite near one end of the chromosome. Humans normally have five pairs of acrocentric chromosomes. Down syndrome is caused by an extra acrocentric chromosome (chromosome21).
Acrocephalosyndactyly: An inherited disorder causing abnormalities of the skull and face and the hands and feet. In acrocephalosyndactyly there is closure too-early of some of the sutures of the skull (craniosynostosis). This results in an abnormally shaped head, which is unusually tall and peaked, and an abnormally shaped face with shallow eye sockets and underdevelopment […]
Acrochordon: A small tag of skin that may have a stalk (a peduncle). An acrochordon may appear on skin anywhere although the favorite locales are the eyelids, neck, armpits (axillae), upper chest, and groin. Invariably benign, this tiny tumor of the skin usually causes no symptoms unless repeatedly irritated as, for example, by the collar. […]
Acrocyanosis: Blueness of the hands and feet, usually due to inadequate circulation.
Acromegaly: Condition due to the production of too much growth hormone by the pituitary gland after the end of adolescence. When there is secretion of too much growth hormone before the end of adolescence, gigantism results. People with pituitary gigantism can truly be giants; they can sometimes end up over 7 or 8 feet in […]