Androgen Insensitivity Syndrome
Return to Library
What is androgen insensitivity syndrome?Androgen insensitivity syndrome is a condition that affects sexual development before birth and during puberty. People with this condition are genetically male, with one X and one Y chromosome. Because their bodies are unable to respond to certain hormones (called androgens), they may have mostly female sexual characteristics or signs of both male and female sexual development (hermaphroditism). Complete androgen insensitivity syndrome occurs when the body cannot use androgens at all. Partial or mild androgen insensitivity syndrome results when tissues are partially sensitive to the effects of androgens. People with partial androgen insensitivity (also called Reifenstein syndrome) can have normal female sexual characteristics, both male and female sexual characteristics, or normal male sexual characteristics. People with mild androgen insensitivity appear male, but are often infertile and tend to develop female breasts at puberty. How common is androgen insensitivity syndrome?Complete androgen insensitivity syndrome affects 2 to 5 per 100,000 live male births. Partial androgen insensitivity is at least as common as complete androgen insensitivity. Mild androgen insensitivity is much less common. What genes are related to androgen insensitivity syndrome?Mutations in the AR gene cause androgen insensitivity syndrome. The AR gene provides instructions to make a protein called an androgen receptor. This protein allows cells to respond to androgens, which are hormones (such as testosterone) that direct male sexual development. Androgens and androgen receptors also have other important functions in both males and females, such as regulating hair growth and sex drive. Mutations in the AR gene prevent the androgen receptor from working properly, which makes cells less responsive to androgens or prevents cells from using these hormones at all. Depending on the level of androgen insensitivity, an affected person's sexual characteristics can vary from mostly female to mostly male. How do people inherit androgen insensitivity syndrome?This condition is inherited in an X-linked recessive pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In males (who have only one X chromosome) one altered copy of the gene in each cell is sufficient to cause the condition. Males are affected by X-linked recessive disorders much more frequently than females. A striking characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. About two-thirds of cases are inherited from mothers who carry an altered copy of the AR gene on one of their two X chromosomes. The remaining cases result from a new mutation in a mother's egg cell before the child is conceived.
Source: National Institutes of Health
|
Free Androgen Insensitivity Syndrome Articles |
|
|
|
|
Researchers from University of Cambridge, Department of Paediatrics detail findings in life sciences
2007 APR 10 -- Research findings, "Regulation of wolffian duct development," are discussed in a new report. According to recent research from Cambridge, the United Kingdom, "Wolffian ducts (WDs) are the embryonic structures that form the male internal genitalia. These ducts develop in both the male and female embryo." "However, in the female they subsequently regress, whereas in the male they are stabilised by testosterone. The WDs then develop into separate but contiguous organs, the epididymis, vas deferens and seminal vesicles. Recently, considerable progress has been made in identifying genes that are involved in these different stages of development which is described in this review. In addition, WD development in (atypical forms of) cystic fibrosis and intersex disorders, such as the complete androgen insensitivity syndrome, 17beta-hydroxysteroid dehydrogenase deficiency and LH-receptor defects, is discussed," wrote S.E. Hannema and colleagues, University of Cambridge, Department of Paediatrics. The researchers concluded: "The apparent increase in male reproductive tract disorders is briefly discussed from the perspective of the potential endocrine-disrupting effects of the numerous chemicals in the environment to which the developing male foetus can be exposed." Hannema and colleagues published their study in Hormone Research (Regulation of wolffian duct development. Hormone Research, 2007;67(3):142-51). For additional information, contact S.E. Hannema, University of Cambridge, Dept. of Paediatrics, Addenbrooke's Hospital, Cambridge, UK. Publisher contact information for the journal Hormone Research is: Karger, Allschwilerstrasse 10, CH-4009 Basel, Switzerland. Keywords: United Kingdom, Cambridge, Life Sciences. This article was prepared by Science Letter editors from staff and other reports. Copyright 2007, Science Letter via NewsRx.com.
|
