Your review hasn't been inserted one review per article per day allowed! X chromosome inactivation is the the process by which most genes on one of the two X chromosomes in females are silenced epigenetically and randomly, and so fail to produce any product. The syndrome was named after Dr.
For example, girls who have an extra sex chromosome an extra X often appear normal physically and mentally and are fertile. Many of these syndromes are not noticed while the mother is pregnant but may be discovered if prenatal testing is done for other reasons, such as older age in the mother.
Chorionic villi sampling and amniocentesis are two common methods where the foetus tissue is extracted and their DNA is isolated and genetically tested for abnormalities. The risk for male breast cancer and osteoporosis is also increased.
These triploid genes present in cells of male, may be what is causing the symptoms for Klinefelter syndrome. Clinical indications that should raise suspicions of a sex chromosome abnormality are:.
Yes No. This is a natural process which can be seen in female mammals, XX. Its incidence is about less common than Klinefelter's and it is present in about 1. The phenotype of the affected person is basically male, tall stature with elongated lower legs and forearms.
Other possible variations include:.
In females, the effect of the mutation may be masked by the second healthy copy of the X chromosome. A gene is a segment of deoxyribonucleic acid DNA and contains the code for a specific protein that functions in one or more types of cells in the body see Genes and Chromosomes for a discussion about genetics.
The syndrome was named after Dr. The Manual was first published as the Merck Manual in as a service to the community.