Androgen insensitivity syndrome (AIS) is a disorder of sexual differentiation that occurs in persons with the 46XY chromosome complement (karyotype) typical of males, but who are partly or totally insensitive to androgens (male hormones). There are two forms of AIS, both of which affect development of the genitals.

In complete androgen insensitivity syndrome (CAIS), the body is completely unresponsive to androgens and develops as female in external anatomy. Internally, the uterus and fallopian tubes are absent and the gonads are testes, not ovaries. The vagina varies in depth from roughly 2/3 normal depth to a short dimple, but can usually be lengthened by non-surgical stretching enough to be adequate for sexual intercourse. Individuals with CAIS appear as girls at birth and invariably grow up as girls. As adults they are usually heterosexual, sexually active, women.

In partial androgen insensitivity syndrome (PAIS), the external anatomy can be similar to that seen in CAIS, only with slight clitoral enlargement, or it can be more masculinized with in-between or "ambiguous" genitalia. There is also form called minimal androgen insensitivity syndrome (MAIS) where the external anatomy is normally or nearly normally male, but the forms that are closer to female in external anatomy are more common.

At puberty, individuals with CAIS do not menstruate because they have no uterus. They remain completely infertile throughout their lives. Breast development is as typical for women, sometimes tending towards over-development. Pubic and armpit hair may be absent or very scanty, and acne seldom develops due to absence of androgen effects. The body form is typically female, averaging slightly taller than the average woman.

In PAIS, pubertal effects are similar, with feminization (breast development), except that there are also varying amounts of androgen effect (virilization), although always less than what occurs in typical males. In those close to typically female in external anatomy, puberty is mainly feminizing, usually with no more androgen effect (pubic and armpit hair) than is typical of women.

External Links

For more information about AIS, visit the website:

http://www.medhelp.org/www/ais

or write to:

aissgusa@hotmail.com