Understanding Fragile X

Fragile X syndrome, or Martin-Bell syndrome, is a genetic syndrome which results in a spectrum of characteristic physical, intellectual, emotional and behavioural features which range from severe to mild in manifestation. Fragile X syndrome (also called FXS) is the most common cause of inherited mental retardation. It is also the most common known cause of autism.  It affects about 1 in 4000 males and 1 in 8000 females.

There are four generally accepted forms of Fragile X syndrome which relate to the length of the repeated CGG sequence:

Normal (29-31 CGG repeats), Premutation (55-200 CGG repeats), Full Mutation (more than 200 CGG repeats), and Intermediate or Gray Zone Alleles (40 – 60 repeats).

6-minute version of the Understanding Fragile X DVD produced by Fragile X Association. Covers symptoms, diagnosis, and treatments.