Fragile X syndrome is a common cause of inherited learning disability and can affect one in 2000 males and one in 4000 females and is due to a mutation at an inherited fragile site on the X chromosome.

The researchers in this study were interested in looking at the behavioural profile of people with fragile X syndrome during adolescence and adulthood.

They worked with 30 Individuals with fragile X syndrome and autism and compared this group with 106 people with fragile X syndrome but not autism and 135 people diagnosed with autism but not fragile X syndrome. They made comparisons on measures of autism symptoms, adaptive functioning, behaviour problems, and psychological symptoms.

They found that those people with a diagnosis of fragile X syndrome and autism had greater communication and social reciprocity impairments than those with fragile X syndrome only. They also found that those in this group also showed higher levels of repetitive and challenging behaviours than either of the comparison groups.

They conclude that this suggests “a unique profile of vulnerability for those diagnosed with both fragile X syndrome and autism.”

Behavioral Phenotype of Fragile X Syndrome in Adolescence and Adulthood, Smith, L et al in American Journal on Intellectual and Developmental Disabilities: January 2012, Vol. 117, No. 1, pp. 1-17