Thứ Ba, ngày 15 tháng 12 năm 2009

Syndrome of androgen insensitivity

The syndrome of androgen insensitivity (AIS) occurs when a person is genetically male (has one X chromosome and one Y chromosome) is resistant to male hormones called androgens. As a result, the person has some or all of the physical characteristics of a woman, despite having the genetic character of a man.

Causes, incidence and risk factors

This syndrome is caused by various genetic defects on the X chromosome, which makes the body unable to respond to the hormones responsible for male physical characteristics.

The syndrome is divided into two main categories:

* Syndrome complete androgen insensitivity
* Syndrome of incomplete androgen insensitivity

The syndrome of complete androgen insensitivity prevents the development of the penis and other male body, which the child is born with female appearance. Complete form of the syndrome occurs in 1 in 20,000 live births.

The degree of sexual ambiguity varies widely in people with the syndrome of incomplete androgen insensitivity. Incomplete AIS can include other disorders such as Reifenstein syndrome (also known as syndrome or Lubs Gilbert-Dreyfus syndrome), which is associated with the development of breasts in men, failure of one or both testes to descend the scrotum after birth and hypospadias, a condition in which the opening of the urethra is on the underside rather than at the tip of the penis.

Also included in the broad category of the syndrome of incomplete androgen insensitivity syndrome is male infertility that is sometimes caused by a disturbance in androgen receptors.
Symptoms

A person with the syndrome of complete androgen resistance appears to be female, but has no uterus and have very little pubic and axillary hair. At puberty, they develop female secondary sex characteristics like breasts, but no presence of menstruation and fertility.

People with the syndrome of incomplete androgen insensitivity may have physical features both male and female. Many of them have partial closure of the outer lips of the vagina, enlarged clitoris and vagina short.

There may be:

* A vagina but no cervix or uterus
* Inguinal hernia with a testicle that can be felt during a physical examination
* Normal female breast development
* Testes in the abdomen or other unusual places in the body

Exams and Tests

The syndrome of complete androgen insensitivity rarely discovered during childhood, unless you feel a lump in the abdomen or groin that turns out to be a testicle surgically when exploring. Most people with this condition are not diagnosed until they fail to menstruate or have difficulty becoming pregnant.

However, the incomplete syndrome, often discovered during childhood because the person may have physical features both male and female.

Tests used to diagnose this condition may include:

Blood tests to check levels of testosterone, luteinizing hormone (LH) and follicle stimulating hormone (FSH)
* Genetic testing (karyotyping)
* Pelvic ultrasound

You can do other blood tests to help differentiate between the syndrome of androgen insensitivity and deficiency of these.
Treatment

Testicular tissue abnormally located can not be removed until a child completes puberty and stop growing. At this point, you can remove the testes because they may develop cancer like any testicle that has not fallen.

The estrogen replacement therapy is prescribed after puberty.

Treatment and gender assignment can be a very complex issue, therefore must be addressed individually with great care.

Expectations (prognosis)

The prognosis for the syndrome of complete androgen insensitivity is good if testicular tissue removed at risk at the appropriate time. The outlook for incomplete AIS depends on the presence and severity of ambiguous genitalia.
Complications

Complications include testicular cancer, infertility, and complex psychosocial issues.
Calling your health care

Call your doctor if you or your child has signs or symptoms of this syndrome.
Alternative Names

Testicular feminization

References

Wysolmerski JJ. Insogna KL. The Parathyroid Glands, Hypercalcemia, and Hypocalcemia. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders, 2008: chap. 266.

Bringhurst FR, Demay MB, Kronenberg HM. Disorders of Mineral Metabolism. In: Kronenberg HM, Schlomo M, Polansky KS, Larsen PR, eds. Williams Textbook of Endocrinology. 11th ed. St. Louis, Mo: WB Saunders, 2008: chap. 27

Androgen insensitivity syndrome


The AIS is a genetic disease in which the hormones responsible for developing male physical characteristics (androgens) are not absorbed by the cells. This creates a disorder in the body and this takes place as if it were a woman.

Androgen-dependent formation of the penis, testicles and body hair. These operate from the seventh week of pregnancy, creating the testes that will stay in the abdominal cavity and eventually fall.

Those affected by the also called testicular feminization, lack of cellular capacity to respond to commands sent to the male hormones, so your body does not develop normally. These hormones are created, as in a healthy man in the testicles that are located in the abdomen and never to descend. For this reason, even though the individual has XY chromosomes, your body develops as a woman. It affects the X chromosome

There are two types of the syndrome of androgen insensitivity (AIS). There is a complete and incomplete AIS. Completely prevents the full development of any male characteristics. The child was born and grew up with absolute feminine appearance. The body is that of a woman, breasts, vagina and hips. The only irregularity is the absence of menstruation. This does not occur because the individual lacks the uterus and ovaries. If performed genetic mapping shows that actually has XY chromosomes but their cells do not respond to androgens.

In the incomplete AIS is a mixture of feminine and masculine characteristics.
For example, there are cases of men who have developed breasts. Also from this evil can be derived from others such as cryptorchidism, which is when one or both undescended testes.

The descent of the testes not can lead to cancer, so it is common to remove them when you discover the evil, which is usually in adolescence. Another common treatment is the use of estrogen to replace the ineffective androgens and start the normal development of female characteristics. This is not a deadly disease and removed promptly if the testes do not produce any complication apart from the obvious infertility. There is a common syndrome, affecting 1 in every 64,000 men.