Androgen Insensitivity Syndrome
What is androgen insensitivity syndrome?
Androgen insensitivity syndrome (AIS) occurs when someone is genetically male but is insensitive to androgens (male sex hormones). This means the person has male sex chromosomes (one X and one Y chromosome) but may have female genitals.
AIS is a disorder of sex differentiation. It was previously called testicular feminization syndrome. It affects male fetuses as they develop in the uterus, as well as sexual development during puberty. AIS prevents male genitals from developing as they should. It almost always results in infertility during adulthood.
Are there different types of androgen insensitivity syndrome?
There are three types of AIS:
- Complete androgen insensitivity syndrome (CAIS): A person’s external genital appears female. But they don’t have female sex organs (no ovaries, fallopian tubes or uterus). People with CAIS are often raised as girls.
- Partial androgen insensitivity syndrome (PAIS): A person’s external genitals may appear partially (not fully) developed male or female or may not be clearly one or the other. People with PAIS are often raised as boys, but not always.
- Mild androgen insensitivity syndrome (MAIS): A person’s genitals appear male, but they’re usually infertile. Some experts consider MAIS a type of PAIS.
Who gets androgen insensitivity syndrome?
Males who inherit an abnormal gene, called the androgen receptor (AR) gene, from their mothers have a 1 in 4 chance of developing AIS. Females can also inherit and carry the gene, but they won’t develop AIS.
How common is androgen insensitivity syndrome?
Androgen insensitivity syndrome is rare. About 1 in 99,000 male infants are born with partial androgen insensitivity syndrome and 2 to 5 per 100,000 are born with complete androgen insensitivity syndrome.
Symptoms and Causes
What causes androgen insensitivity syndrome?
AIS is the result of an abnormal X-linked gene, meaning it’s a gene on the X chromosome and the mother passes it to her child. The gene can’t produce androgen receptors. These are cells that allow your body to respond to androgens, such as testosterone.
What are the symptoms of androgen insensitivity syndrome?
The most common symptom across all forms of AIS is infertility. People with CAIS won’t be able to get pregnant or make their partners pregnant. They have genitals that appear female, but they don’t have female reproductive organs. It’s very rare for people with PAIS or MAIS to make their partners pregnant. Even if they have a very small penis, sperm production is usually low or non-existent.
Other signs and symptoms of CAIS include:
- Abnormally tall stature for a female during puberty.
- Amenorrhea (no menstrual periods).
- Little or no pubic hair or underarm hair during puberty.
- Narrow or shallow vagina.
- Undescended testicles (testicles that are still in your abdominal cavity).
Other signs and symptoms of PAIS can include:
- Bifid scrotum (scrotum splits in two).
- Clitoromegaly (large clitoris).
- Gynecomastia (enlarged male breast tissue).
- Hypospadias (the urethra’s hole is on the underside of your penis instead of the tip).
- Labial adhesions (lips of skin around your vagina seal shut).
- Micropenis (abnormally small penis).
- Partially undescended testicles.
Other signs and symptoms of MAIS include:
- Sparse body hair.
Diagnosis and Tests
How is androgen insensitivity syndrome diagnosed?
A healthcare provider can often diagnose PAIS right after birth by looking at a baby’s genitals. But CAIS or MAIS might not be evident until the age of 11 or 12 when puberty begins. This is the time when a healthcare provider might notice issues. A child with CAIS may not be having menstrual periods or have any pubic hair. A child with MAIS might continue having a very small penis or develop breast tissue. Puberty is also when undescended testicles can herniate, or bulge through an opening in the abdominal wall. Sometimes, healthcare providers discover undescended testicles if your child has surgery for an inguinal hernia.
What tests help diagnose androgen insensitivity syndrome?
Your healthcare provider will need to do tests to confirm a diagnosis:
- Blood tests check hormone levels, sex chromosomes and genetic abnormalities.
- Imaging exams, such as ultrasound, can confirm the absence of female reproductive organs.
If you have a family history of AIS, you may choose to have genetic testing if you’re considering having children. These tests can tell you if you’re a carrier of the abnormal gene.
Management and Treatment
How is androgen insensitivity syndrome treated?
Treatment for AIS depends on sex assignment, which is the gender chosen for an infant at birth. Most treatments take place after puberty. This gives your child’s body time to go through developmental changes. It also allows your child to play a more active role in their treatment decisions.
But some health experts think certain treatments, such as removal of the testicles, should happen before puberty. They think other treatments can happen after the completion of puberty. This reduces the risk of gonadoblastomas, which are tumors that can form in undescended testicles.
Children raised as males may choose to have:
- Surgery to repair their male genitals, such as hypospadias repair or orchiopexy (surgery to move undescended testicles to the scrotum).
- Breast reduction surgery to remove excess breast tissue.
- Hernia repair to close open or weakened tissue in their abdominal wall.
- Hormone therapy with testosterone.
Children raised as females may choose to have:
- Surgery to remove male genitals or extra clitoral tissue.
- Nonsurgical vaginal dilation to make their vagina deeper.
- Hormone therapy with estrogen.
Parents and healthcare providers may decide not to assign a gender at birth. Sometimes, they wait until puberty to choose one. Or parents might want the child to choose their own gender identity.
How can I prevent androgen insensitivity syndrome?
There’s no way to prevent AIS. If you have a family history of the disease and worry about passing the abnormal gene to your child, genetic testing can help you find out if you’re a carrier.
Outlook / Prognosis
What’s the prognosis (outlook) for people with androgen insensitivity syndrome?
People with AIS can lead full, healthy lives. Most people respond well to treatments like hormone therapy and surgery. But AIS usually results in infertility, which can be difficult for many people. It can also have profound psychological effects on children and young adults. Your risk of testicular tumors also increases by about 30% without a gonadectomy (removal of gonads).
If my child has androgen insensitivity syndrome, how can I help them?
Caring for your child’s psychological health is a huge part of managing AIS. A strong support system of healthcare providers, friends and family members who understand their condition is important. Support groups can also help your child share their experiences with others who are going through similar challenges. It’s important to talk with your child about their AIS around the time of puberty. That’s when they’ll notice a lack of pubertal progression.
As an adult, how can I cope with androgen insensitivity syndrome?
AIS presents many challenges for adults. You may struggle to have a normal sex life or find a partner who understands and accepts your condition. Infertility can also have a profound emotional effect on many people.
Some older children or adults may develop gender dysphoria. This is distress or dissatisfaction with their gender identity assigned at birth. They may choose to transition from one gender to another. This change is a complex physical and emotional process.
If you have AIS, it may help to talk with a counselor or therapist about your experiences. Support groups can help you connect with others who have AIS.
A note from Cleveland Clinic
People with androgen insensitivity syndrome (AIS) are genetically male. But they may have female genitals or a combination of male and female genitals. The disorder can present a variety of challenges, from gender identity issues to infertility. It’s important for people with AIS to stay in close communication with their healthcare providers and form a strong emotional support system.
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