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Monday, February 13, 2006
(androgen insensitivity syndrome,AIS;
complete androgen insensitivity)
This is an intersex condition, in which the reproductive organs differ from the genetic sex of the person. Affected individuals are born with female external genitalia and are thought to be females at birth.

At purberty, their breasts develop, and though they usually have little body, they otherwise have normal female appearance. However, the CHROMOSOMES are those of a male; an XY chromosome pair, rather than the XX found in normal females.

Every FETUS, whether genetically male (XY) or female (XX), starts life with the capacity to develop either a male or female reproductive system. All fetuses have undifferentiated, non-specific genitals for the first few weeks after conception. After a few weeks, in an XY fetus (without AIS), these non-specific genitals develop inside the body and start to produce androgens. IN AIS, the child is onceived with male (XY) sex chromosomes. Embryonic testes develop inside the body and start to produce androgens. In AIS, these androgens cannot complete the male genital development due to a rare inability to use the androgens that are being produced by the testes. The problem lies in the androgen receptor GENE on the X CHROMOSOME received from the mother. This affects teh responsiveness, or sensitivity, ot the fetu's body tissues to androgens. The developmenty of the external genitals continues along female lines, but another hormone produced by the fetal testes acts normaly and suppresses the development of female internal organs. Thus a person with AIS has external genitals that are completely female. However, internally there are testes instead of uterus and ovaries.

Affected individuals typically come to medical attention when they fail to begin menstruating at the time of puberty. Upon examination, the vagina is shallow, and there are ni Fallopian tubes or uterus. The testicles may be in teh abdominal atrea and are incapable of producing viable sperm.

The testes are generally removed and plastic surgery can enlarge the size of the vagina, enabling continued female gender identification. (Some physician suggest that affected males never be told their true genetic sex for psychological reasons.However, most professional now view the witholding genetic and gonadal information as an old-fashioned and paternalistic attitude and recommend full disclosure with psychological support and counseling.)

Following treatment and continued estrogen theraphy, affected individuals live as normal women. Although they are sterile. Life span and intelligence are normal.

It has been proposed by one genetic researchers that Joan of Arc was actually a male with this SYNDROME. The suggestion is based on examination of extensive documentation of her physical characteristics presented at her trial for heresy in 1431 and at her posthumous Trial of Rehabilitation in 1456. This documentation includes accounts by those who lived in close quarters with her that while she had well-developed breasts, she has had no pubic hair and did not menstruate. This hypothesis had led to specualtion concerning elevated testosterone levels and her behavior. The same suggestion had been made regard Queen Elizabeth I, England's "Virgin Queen" (1533-1603)

A nationwide registry of Danish patients suggested an incidence of one in 20,400 male births. The androgen receptor gene is locted on teh X chromosome, and the disorder is therefore an X-LINKED trait. In about two-thirds of cases, AIS is inherited from the mother. The other third result from spontaneous MUTATION in the fetus. CARRIER females can be detected by biochemical means and PRENATAL DIAGNOSIS has been accomplished by CHORIONIC VILLUS SAMPLING.

(Source: GENETIC DISORDERS AND BIRTH DEFECTS BY: James Wynbrandt and Mark D. Ludman, MD., FRCPC)
posted by infraternam meam @ 12:04 AM  
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Name: infraternam meam
Home: Chicago, United States
About Me: I am now at the prime of my life and have been married for the past 25 years. Sickly at times, but wants to see the elixir vita, so that I will be able to see my grandchildren from my two boys.
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