Androgen Insensitivity Syndrome

AIS occurs in a range of forms, from complete to mild. Most mutations to the testosterone-binding region, and some other types of mutations, cause complete androgen insensitivity syndrome (CAIS). In this form of the syndrome, the XY person is born phenotypically female, and from birth is raised as a girl. Gender identification (the internal sense of being male or female) is female. Sexual orientation is typically heterosexual, and so most CAIS individuals are attracted to males. At puberty, estrogen production by the adrenal glands causes breasts to develop. However, no pubic or armpit hair develops, since in males and females this is controlled by testosterone, and no menstruation occurs. It is at this point that the condition is usually diagnosed. Once discovered, the testes are usually surgically removed to prevent the possibility of testicular cancer, which is more common in people with CAIS. The woman is infertile, but may be able to enjoy sexual relations if the vagina is long enough to prevent pain during intercourse; or, if the vagina is not long enough, it can be surgically lengthened. CAIS is thought to occur in 2 to 5 births per 100,000.

Those with partial androgen insensitivity syndrome (PAIS) have androgen receptors that are partially responsive to testosterone, and a range of outcomes may result. A person with PAIS may be born with external genital structures that are not typically male or typically female, a condition called intersexuality. The appearance of the genitals may range from predominantly male to predominantly female. There may be a very small penis or enlarged clitoris, abnormalities in the location of the urethra, and partial fusion of the labia. Breasts may develop in males at puberty. Internal gender identification may be with either sex. PAIS is thought to be as common as CAIS.

Ambiguous genitals are often surgically altered at birth. Problems arise when the surgically assigned sex conflicts with the internal gender identification, which develops early and becomes even more pronounced through late childhood and puberty. Increasing understanding of PAIS and sensitivity to the issues of gender identification have brought new awareness about the potential for these problems, but the practice of surgical sex assignment is still common. In 2001 the British Association of Paediatric Surgeons recommended that surgery "only be undertaken with considerable caution and following full multidisciplinary investigation and counseling of the parents." Other therapies include hormone treatments and psychological counseling, including family counseling, and these are often part of the treatment, with or without surgery.