Androgen insensitivity syndrome


Androgen insensitivity syndrome

Description, Causes and Risk Factors:

Abbreviation: AIS.

Androgen insensitivity syndrome is a genetic disorder in which the XY fetus is unresponsive (insensitive) to androgens. Androgens are male hormones, such as testosterone. A baby with androgen insensitivity syndrome is born externally like a normal girl. However, internally they have a short blind-pouch vagina, and no ovaries, fallopian tubes or womb (uterus). The testes are in the inguinal canal or abdomen.

In other words, androgen insensitivity syndrome is a condition in which the development of the genitals and reproductive organs are affected.

Very early on, all unborn babies have identical genitals, regardless of whether they are female or male. A pair of sex chromosomes in the baby - XX or XY - determines whether they develop male (XY) or female (XX) genitals and reproductive organs.

Androgen insensitivity syndrome is caused by various genetic defects on the X chromosome that make the body unable to respond to the hormones responsible for the male appearance.

Androgen insensitivity syndrome

The syndrome is divided into two main categories:

    CAIS (complete androgen insensitivity syndrome).

  • PAIS (Partial androgen insensitivity syndrome).

Complete androgen insensitivity prevents the development of the penis and other male body parts. The child born appears to be a girl. The complete form of the syndrome occurs in as many as 1 in 20,000 live births.

Grades:

    Grade 1 (PAIS) - the individual has male genitals and is likely to be infertile.

  • Grade 2 (PAIS) - there are predominantly male genitals, which are small. The urethra may not end at the end of the penis, but at the underside of the shaft or somewhere else (hypospadia). The child may have undescended (internal) testes (testicles) - known as cryptorchidism.

  • Grade 3 (PAIS) - there are predominantly male genitals, however they are very small. Possible hypospadias and internal (undescended) testes.

  • Grade 4 (PAIS) - genitals are ambiguous. There may be a penis, but it is impossible to tell whether it is a clitoris or a penis (phallic structure that is indistinguishable between a penis and a clitoris).

  • Grade 5 (PAIS) - genitals are essentially female, with separate urethral and vaginal passages. The clitoris may be larger than normal.

  • Grade 6 (PAIS) - the genitals are female, and there is pubic and underarm hair.

  • Grade 7 (CAIS) - the genitals are female, but there is no (or very little) pubic and underarm hair.

Symptoms:

A person with CAIS appears to be female but has no uterus, and has very little armpit and pubic hair. At puberty, female secondary sex characteristics (such as breasts) develop, but menstruation and fertility do not.Persons with PAIS may have both male and female physical characteristics. Many have partial closing of the outer vaginal lips, an enlarged clitoris, and a short vagina.

There may be:

    A vagina but no cervix or uterus.

  • Inguinal hernia with a testis that can be felt during a physical exam.

  • Normal female breast development.

  • Testes in the abdomen or other unusual places in the body.

The degree of sexual ambiguity varies widely in persons with PAIS. PAIS is associated with breast development in men, failure of one or both testes to descend into the scrotum after birth, and hypospadias, a condition where the opening of the urethra is on the underside, rather than at the tip, of the penis.

Diagnosis:

CAIS 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 people with this condition are not diagnosed until they fail to menstruate or have difficulties becoming pregnant.

PAIS, however, is often discovered during childhood because the person may have both male and female physical characteristics.

Tests used to diagnose this condition may include:

    Blood work to check levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH).

  • Genetic testing (karyotyping).

  • Pelvic ultrasound.

Other blood tests may be done to help tell the difference between AIS and androgen deficiency.

Treatment:

Children with CAIS are usually raised as girls because they have female genitals. In other cases the parents will have to decide whether their child should be raised as a son or daughter - this may be difficult decision if the child has PAIS and their genitals have both male and female features.

Parents should receive advice and counseling from psychologists and medical specialists regarding their child's future development, and the gender that child is most likely to identify with.

The majority of children with PAIS continue keeping the gender they were assigned when they were born. However, some may feel this does not represent their true identity, and change their gender.

Options Include:

    Genital reconstructive surgery - this used to be done when the child was very young and a gender had been assigned to him/her. However, these days most doctors postpone genital reconstructive surgery until the child is old enough to decide what to do.

  • Orchidectomy (removing the testes) - women with CAIS are advised to have their testes surgically removed, mainly because they can become cancerous.

  • Orchidectomies used to be performed when the child was very young. These days, however, doctors prefer to wait until the girl has completed puberty. The testes can help convert androgen (the male hormone) to estrogen (the female hormone), allowing the girl to develop a normal female body without hormone treatments being required.

  • Orchiopexy - surgery to bring down an undescended testis to the scrotum. Boys with hypospadias - in which the urethra does not end where it should, at the tip of the penis - may need surgery to straighten their penis to that they can urinate standing up.Lengthening the vagina - this is done to make sexual intercourse easier. Doctors used to recommend doing this procedure before puberty. Now they tend to wait until after puberty so that the woman can decide whether to have it done. A method called dilation, in which the vagina is gradually widened and deepened with the use of small plastic rods is usually used. Vaginoplasty, a surgical procedure is also possible.

  • Clitoris reduction - a woman with PAIS (partial androgen insensitivity syndrome) may decide to have her clitoris surgically reduced, and her vaginal opening enlarged. There is a risk of losing some sensitivity in the clitoris, although losing the ability to reach orgasm is very rare.

  • Hormone therapy - this may be required for women with CAIS who have had their testes removed and have completed puberty. They will have to take estrogen supplements to prevent menopausal symptoms, including the developing of osteoporosis (weak bones). Estrogen may also stop them from becoming too tall - their Y chromosome carries genes for extra height.

  • Some children with PAIS may also require hormone supplements. Girls who have undergone an orchidectomy (removal of testes) may require a combination of androgen and estrogen to encourage female development. Boys with PAIS may require androgen supplements to encourage certain male features, such as the growth of facial hair and the deepening of their voice.

NOTE: The above information is educational purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.

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