Androgens are a type of hormone. They are sometimes called “masculinizing” hormones because relatively high levels of androgens in the womb usually make a fetus’s genitals develop as the male type. Testosterone is one type of androgen that is produced by the testes. The adrenal glands – organs that both males and females have in the back of their bodies above the kidneys – also make androgens.
For androgens to have an effect on the body, it isn’t enough for the body to make the androgens; the cells in the body have to be able to respond to those androgens. Sometimes, though, a person’s cells do not respond to androgens because her or his cells lack “androgen receptors.” (Think of it has having a set of keys but no locks to put the keys into.)
Androgen Insensitivity Syndrome (AIS) is a condition in which the cells of a person’s body do not respond in the usual ways to androgens because the person’s cells lack the receptors.
If a girl or woman has complete AIS, that means that, so far as we know, her body does not respond to any androgens. In such a case, the girl or woman has an XY chromosomal component, which is usually found in males. In the womb, she developed testes. The testes started making testosterone. But her body lacked the receptors to respond to that testosterone. As a consequence, her genitals developed much more along the lines of the typical female pathway. She developed labia, a vagina, a clitoris, and so on. Her brain development would also be much closer to the female typical pathway (except insofar as the typical female – who is XX and has androgen receptors – will have had some androgen effects on her brain because her adrenal glands make androgens to which her brain cells respond).
Many women with complete AIS report that they were not diagnosed until well into puberty. That’s because often no one suspects a DSD until they go through puberty and don’t menstruate. When girls with complete AIS reach puberty, their testes function as testes normally do at puberty: they generate higher levels of testosterone. But again, the cells cannot respond. Usually some of that testosterone is converted to estrogen, a hormone to which their bodies can respond. As a consequence, these girls may at puberty develop the rounded breasts and hips typical of females. They do not develop the typical quantity of body hair (pubic, arm, armpit, and leg hair), because that requires androgen receptors. They do not menstruate because they do not have ovaries or a uterus.
It is also possible for a person with XY chromosomes to have incomplete or partial AIS. In those cases, how many male-typical or female-typical (or in-between) characteristics the person develops will depend on her or his particular condition.
The main support group for AIS in the United States is the AIS-DSD Support Group. For the website of the AIS-DSD Support Group, click here. The main support group for AIS in the United Kingdom is the Androgen Insensitivity Syndrome Support Group (AISSG). For the website of the AISSG in the UK, click here.
Posted in: Specific Conditions