Clinical Trial: X-chromosome Inactivation, Epigenetics and the Transcriptome

Study Status: Completed
Recruit Status: Completed
Study Type: Observational




Official Title: X-chromosome Inactivation, Epigenetics and the Transcriptome

Brief Summary:

The human genetic material consists of 46 chromosomes of which two are sex chromosomes. The sex-chromosome from the mother is the X and from the father the Y-chromosome. Hence a male consist of one Y and one X chromosome and a female of 2 X-chromosomes. Alterations in the number of sex-chromosomes and in particular the X-chromosome is fundamental to the development of numerous syndromes such as Turner syndrome (45,X), Klinefelter syndrome (47,XXY), triple X syndrome (47,XXX) and double Y syndrome (47,XYY). Despite the obvious association between the X-chromosome and disease only one gene has been shown to be of significance, namely the short stature homeobox gene (SHOX). Turner syndrome is the most well characterized and the typical diseases affecting the syndrome are:

  • An Increased risk of diseases where one's own immune system reacts against one's own body (autoimmune diseases) and where the cause of this is not known; For example diabetes and hypothyroidism.
  • Increased risk of abortion and death in uteri
  • Underdeveloped ovaries with the inability to produce sex hormones and being infertile.
  • Congenital malformations of the major arteries and the heart of unknown origin.
  • Alterations in the development of the brain, especially with respect to the social and cognitive dimensions.
  • Increased incidence obesity, hypertension, diabetes and osteoporosis.

In healthy women with to normal X-chromosomes, the one of the X-chromosomes is switched off (silenced). The X-chromosome which is silenced varies from cell to cell. The silencing is controlled by a part of the X-chromosome designated XIC (X-inactivation center). The inacti