Androgen insensitivity syndrome (AIS) is a genetic condition that mostly affects males. Some females may display very mild symptoms. Individuals with AIS have genetic defects that affect the development of physical traits and characteristics normally associated with males; traits and characteristics normally associated with females may develop in males with AIS.
Depending on the severity of the mutation affecting the androgen receptor, individuals with AIS can experience a range of symptoms. In the most severe cases, individuals with AIS have a completely female body with external female genitalia, but with no uterus, fallopian tube, or ovaries. However, they may have testes in the abdomen. In less severe cases, individuals with AIS have a normal male body, with internal and external male genitalia, but they have problems with sperm production and reduced fertility. The severity of the symptoms depends on the severity of the mutation affecting the androgen receptor, and how much activity the androgen receptor still has.
AIS is caused by mutations, or errors, in the androgen receptor, which is a protein on the surface of cells that responds to the hormone testosterone (and to a form of testosterone called dihydrotestosterone). In unaffected males, the androgen receptor plays an important role in initiating the development of male traits and characteristics. In males with AIS, the androgen receptor is not functioning properly so male traits do not develop normally.
Currently, there is no known cure for AIS. Depending on the specific symptoms, an individual with AIS may choose to identify with either the male gender or the female gender. Based on this decision, a number of options exist to treat the condition, including surgical procedures, such as vaginal construction, breast reduction, and gonadectomy (removal of the testes from patients that appear female). In addition, genetic and psychological counseling is available for patients and their parents.
AIS, androgen receptor, androgen resistance syndrome, CAIS, complete androgen insensitivity syndrome, infertility, PAIS, partial androgen insensitivity syndrome, Reifenstein syndrome, testes, testosterone, X-linked.