What is androgen insensitivity syndrome (ais)?

What is androgen insensitivity syndrome (ais)?

Androgen insensitivity syndrome is a genetic disorder, in which a male, or XY, fetus, does not respond to male hormones. It affects the development of the genitals and the reproductive system.

Male hormones are called androgens, and they include testosterone.

A newborn with androgen insensitivity syndrome (AIS) appears to be a girl, but the reproductive features will be unusual. There may be a short blind-pouch vagina, and no ovaries, fallopian tubes or womb. The testes may be in the inguinal canal or abdomen.

Androgen insensitivity syndrome is rare. It affects between 2 and 5 people in every 100,000.

It is an intersex condition, and it is different from gender dysphoria, or "being transgender." A person with gender dysphoria has reproductive organs and genitals that develop normally, but they feel that their gender is wrong.

Individuals with AIS have a normal life expectancy, but hormone therapy and psychological support may be necessary.

What are XX and XY sex chromosomes?

Sex chromosomes are a pair of DNA molecules, called X or Y, that determine a person's sexual development.

If a male develops breasts during puberty, this could be a sign of AIS.

  • A female has two X chromosomes known as XX
  • A male has one X and one Y chromosome, or XY.

The Y chromosome stimulates the development of the testes and stops the female ovaries from developing. If there is no Y chromosome, the female reproductive system and genitals develop automatically.

An infant who is born with XY chromosomes should develop male genitals and reproductive organs. The testes, or testicles, are the male reproductive organs that produce androgens, or male hormones. These hormones trigger the development of male characteristics and sex organs, such as the penis.

Causes of androgen insensitivity syndrome

For the first 8 weeks of gestation, both male and female embryos have the same genitals. Either a female or male reproductive system can develop. A pair of sex chromosomes will determine which genitals and reproductive organs they develop.

A healthy XY embryo will develop male genitals, because the testes will release androgens, or male hormones.

A person with androgen insensitivity syndrome will not react to the androgen, because a genetic alteration leads to a low number of androgen receptors. A complete absence of reaction will lead to complete androgen insensitivity syndrome.

The testes will stay inside the body instead of coming down to the scrotum. The genitals will resemble those of a female.

In 70 percent of cases, the mutated gene is inherited from the mother, who is a carrier.

A female with one faulty X chromosome may be a carrier. Her female offspring may be carriers and her male offspring may have the condition.

Other cases are thought to result from a fault that occurs either when the mother's eggs are formed, or in an embryo cell soon after conception, but the exact reason is unknown.

Types of androgen insensitivity syndrome (AIS)

There are three forms of androgen insensitivity syndrome

A person with complete androgen insensitivity syndrome (CAIS) will have female external genital features, and they will probably grow up as a female.

In partial androgen insensitivity syndrome (PAIS), there is some sensitivity to androgen. Depending on the level of sensitivity, the person may appear completely male or female, or they may have some features of both.

There may be a slightly enlarged clitoris or a penis which is almost fully formed.

Children born with this condition may grow up as girls or boys, depending on their degree of androgen sensitivity and subsequent genital development.

Mild androgen insensitivity syndrome (MAIS) affects boys, who may form breast tissue during puberty. There may also be difficulty in producing effective sperm.

AIS can be graded from 1 to 7. Grade 7 refers to complete androgen insensitivity syndrome, and grade 1 to 6 are partial. With grade 7, the genitals appear as female, while a person with grade 1 will have male genitals but is likely to be infertile.

Signs and symptoms of androgen insensitivity syndrome

Infertility is a common sign of AIS, although it does not feature in very mild cases.

Females born with AIS will be infertile, because their internal reproductive organs will not develop, due to the testes in the body producing male hormones. Females born with AIS do not have a womb, fallopian tubes, or ovaries.

Complete androgen insensitivity syndrome (CAIS)

If a girl has an inguinal hernia, it may be due to undescended testes. Between 0.8 percent and 2.4 percent of inguinal hernias in girls are due to CAIS.

There are normally no external signs or symptoms at birth, and the condition may not appear until the individual reaches puberty and does not develop pubic or underarm hair, and menstruation does not begin.

Females will have a short, "pouch" vagina.

Partial androgen insensitivity syndrome (PAIS)

Androgen insensitivity will affect child development. An individual with high insensitivity will develop as girls during adolescence. Those with low insensitivity will develop as boys, but breasts may start to develop.

Sometimes, a child grows up as a boy but develops more female traits as puberty arrives. Hormone therapy may help direct puberty towards a specific gender, and it can postpone puberty until the child is old enough to decide which gender is appropriate.

Diagnosing androgen insensitivity syndrome (AIS)

Androgen insensitivity may be diagnosed at birth if the genitals look unusual, for example, if they do not match those predicted by a prenatal amniocentesis.

A hernia can be a sign of undescended testes.

During pregnancy, chorionic villus sampling (CVS) may reveal AIS. In CVS, cells are taken from the placenta for testing.

If a woman has an inguinal hernia, is experiencing difficulty conceiving, or has problems with sexual intercourse, a physician may diagnose AIS.

A blood test can confirm a diagnosis by measuring hormone levels, and detect the altered X chromosome.

An ultrasound scan highlights the soft tissues and cavities inside the body. This may confirm the absence of a uterus, fallopian tubes, and ovaries.

AIS is rare. Unborn babies are not routinely tested, unless there is a family history.

Treatment for androgen insensitivity syndrome

Children with CAIS are usually raised as girls because they have female genitals, but sometimes the parents will have to decide whether to raise their child as a male or a female. This can be difficult if the genitals have both male and female features.

Counseling can help parents and children to know what to expect, and it can help establish the gender that child is most likely to identify with.

Most children with PAIS keep the gender they were assigned at birth, but some feel this does not represent their true identity, and they opt to change.


Genital reconstructive surgery used to be done when the child was very young and a gender had been assigned, but nowadays, it is normally postponed until the child can decide.

If a woman has testes, an orchidectomy may be advised to remove them, because they can become cancerous. This is normally done after puberty, as the testes can help convert androgen, the male hormone, to estrogen, the female hormone, allowing the girl to develop a normal female body without needing hormone treatments.

Orchiopexy is a surgery to bring down an undescended testis to the scrotum.

Surgery to lengthen the vagina can make sexual intercourse easier. Nowadays, this is normally done after puberty, so that the woman can make her own decision.

Some women opt to have the clitoris surgically reduced and the vaginal opening enlarged. This may lead to a partial loss of sensitivity in the clitoris.

Women with complete androgen insensitivity who have their testes removed may undergo hormone therapy after completing puberty. Estrogen supplements can prevent menopausal symptoms, including the development of osteoporosis, and can also stop them from becoming too tall, as their Y chromosome carries genes for extra height.

If the testes are removed at a young age, hormone treatment may begin around 10 or 11 years, to initiate puberty.

Boys with partial insensitivity may need androgen supplements to encourage certain male features, such as the growth of facial hair and the deepening of their voice.

Psychological support is crucial for both the individual with the condition and for their parents.

Androgen Insensitivity Syndrome (Video Medical And Professional 2020).

Section Issues On Medicine: Disease