Androgen Insensitivity

Androgen insensitivity is a rare genetic condition in which a baby that is genetically male (has one X and one Y chromosome) is resistant or unresponsive to male hormones in the body.  These hormones are called androgens and can cause the child to develop outwardly as a female. Internally, however, the female reproductive organs are missing and male gonads are present.

Patients can be seen by Texas Children's experts in Pediatric and Adolescent Gynecology.

Causes & Risk Factors

A baby's genetic sex is determined at conception when the child inherits a pair of sex chromosomes: an X from the mother and either an X or Y from the father. If the baby inherits an X chromosome from both parents, it is a genetic female (XX). If it inherits the Y chromosome from the father, it is a genetic male (XY chromosomes).

Androgen insensitivity is caused by genetic defects of the androgen receptor gene on the X chromosome. These defects prevent the body from using the male hormones that are responsible for a masculine appearance.

Symptoms & Types

Symptoms vary depending on whether the condition is complete or partial, but may include:

• Absence of a menstrual cycle, due to an absent uterus
• Little or no pubic and armpit hair
• No acne during puberty
• Hernias or lumps in the groin or abdomen (which are actually testes)
• A short vagina
• Infertility
• External genitals that aren't clearly male or female (ambiguous genitalia) in some cases

There are two forms of the condition:

• Complete androgen insensitivity – prevents the development of the penis and other male body parts, so externally the child develops as a girl

• Partial androgen sensitivity – the child’s external genitals aren't clearly male or female (ambiguous genitalia)

Diagnosis & Tests

Complete androgen insensitivity is typically discovered at puberty, when a girl fails to start having periods or doesn’t develop pubic or underarm hair.  Occasionally, a diagnosis is established earlier if male gonads are found at the time of an inguinal hernai repair in girls.

Diagnosis starts with a thorough medical history and physical exam, including a pelvic exam.

Additional testing may include:

• Blood test – to check hormone levels
• Genetic testing
• Pelvic ultrasound or MRI pelvis – to create images of the internal organs, confirming the absence of internal female reproductive organs

Partial androgen insensitivity is usually discovered when the baby is born because the external genitals aren't clearly male or female (ambiguous genitalia).

Treatment & Care

Treatment depends on the individual patient and their symptoms, but may include:

• Surgery – to remove testes located in the abdomen or groin, which can become cancerous
• Lengthening of the vagina – either through dilators, small tubes used to stretch the area, or through surgery
• Clitoral reduction
• Hormone replacement therapy
• Counseling – to help the girl and her family deal with the emotional and psychological challenges of the condition