Androgen insensitivity syndrome

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Male reproductive anatomy

Testicular feminization

In its classic form (complete androgen resistance), the person appears to be female but has no uterus, and has sparse armpit and pubic hair. At puberty, female secondary sex characteristics (e.g., breasts) develop, but menstruation and fertility do not.

Complete AIS is rarely discovered during childhood, unless a mass is felt in the abdomen or groin that turns out to be a testicle when it is explored surgically. Most with this condition are not diagnosed until they fail to menstruate or they try to become pregnant and find that they are infertile.

Incomplete AIS, however, is often discovered during childhood because a person may have both male and female physical characteristics. Many have partial fusion of the outer vaginal lips, an enlarged clitoris, and a short, blind-ending vagina.

The individual is often diagnosed because of ambiguous genitalia. Sometimes, though, the person has primarily male characteristics and the only symptom is a low sperm count as an adult, perhaps with breast enlargement.

Signs may include:

• Vagina present but no cervix or uterus
• Normal female breast development
• Testes in the inguinal canal, labia, or abdomen
• Inguinal hernia with palpable gonad

Tests:

• Testosterone levels -- in the male range
• XY Karyotyping -- the presence of one X and one Y sex chromosome indicates male gender
• Luteinizing hormone (LH) levels -- high
• Follicle-stimulating hormone (FSH) levels -- normal
• Sonogram -- shows an absent uterus or intra-abdominal testes
• Androgen receptor studies (research setting) may confirm the syndrome

Tests which may distinguish androgen resistance from androgen deficiency (or 5-alpha reductase deficiency):

• Increased basal and hCG-induced testosterone
• Normal dihydrotestosterone

Review Date: 08/11/2006
Reviewed By: Robert Hurd, MD, Department of Biology, College of Arts and Sciences, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network.