The loss of hearing that occurs or develops some time during a person’s life but was not present at birth.
Acquired deafness contrasts to congenital deafness which is present at birth.
The distinction between acquired and congenital deafness specifies only the time that the deafness appears. It does not specify whether the cause of the deafness is genetic (inherited).
Acquired deafness may or may not be genetic. For example, it may be a manifestation of a delayed-onset form of genetic deafness. Or acquired deafness may be due to damage to the ear from noise.
Congenital deafness similarly may or may not be genetic. For example, it may be associated with a white forelock and be caused by a genetic disease called Waardenburg syndrome. Or congenital deafness may be due to something such as the rubella virus to which the mother was exposed during pregnancy.
- Acquired immunity
Acquired immunity: Immunity acquired by infection or vaccination (active immunity) or by the transfer of antibody or lymphocytes from an immune donor (passive immunity). Acquired immunity is in contrast to innate immunity (natural immunity).
- Acquired immunodeficiency syndrome
AIDS. AIDS is a disease due to infection with the human immunodeficiency virus (HIV). Also referred to as acquired immunodeficiency disease.
- Acquired mutation
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 […]