This site is intended for healthcare professionals

account_circleSign in
Go to /sign-in page

You can view 5 more pages before signing in

Mental retardation group

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

To date, there are three distinct mutations on the X-chromosome which produce mental retardation. They are combined into the congenital fragile X syndrome.

The genetic lesions are characterized by:

  • expansion of CGG/CCG repeats
  • very large numbers of repeats, typically 200-2000 in affected individuals
  • there is marked genetic anticipation; larger numbers of repeats result in early onset and severe disease
  • the CGG/CCG repeats are transcribed into non-coding regions of mRNA's

Related pages

Create an account to add page annotations

Create a free account

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.