ABSTRACT
The National Fragile X Foundation defines this condition as follows: Fragile X is the most common identifiable cause of inherited intellectual disability. It can cause a wide range of difficulties with learning, as well as social, language, attention, emotional and behavioural problems. It occurs in children from any social or ethnic background. It derives its name from the presence of an unusual chromosomal finding called the fragile X site. Specifically, the fragile X site describes a portion of chromosomal material located on the bottom of the X chromosome which looks as though it is hanging by a thread from the main body of the chromosome. The appearance is caused by an excess DNA material which prevents normal coiling of the DNA to form a chromosome. This interferes with production of the fragile X protein which is thought to be important for normal brain development. Chromosome testing used in the past to diagnose an individual with fragile X syndrome.
