Circle of Angels Research Fund - Rett Syndrome / Part 2.

Most individuals with Rett syndrome are female. One explanation given for this was that the genetic defect that caused Rett syndrome in females caused embryonic lethality in males (that is, males with disease-causing MECP2 mutations died before they were born). While a plausible hypothesis, more recent research has contradicted this explanation. The incidence of Rett in males is unknown.The severity of Rett syndrome in females can vary depending on the type and position of the MECP2 mutation and the pattern of X-chromosome inactivation. It is generally assumed that 50% of a female's cells use the maternal X chromosome while the other 50% uses the paternal X chromosome (see X-inactivation). However, if most cells in the brain activate the X chromosome with the functional MECP2 allele, the individual will have very mild Rett syndrome; likewise, if most neurons activate the X chromosome with the mutated MECP2 allele, the individual will have very severe Rett syndrome just as males with MECP2 mutations do (as they only have one X chromosome).

Channel: People & Blogs
Uploaded: November 30, 1999 at 12:00 am
Author: SzChristie

Length: 05:17
Rating: 4.33
Views: 966

Tags: Autism  Diseases  Rett  Syndrome  

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