Autism and the fragile X syndrome.

The fragile X chromosome is an important factor in inherited mental retardation in males. It has also been reported that infantile autism is associated with fragile X. Recently, an article reported an examination of a small sample of autistic children in whom the fragile X chromosome was not found. Its authors concluded that if an association between fragile X and autism exists, it is infrequent. In the present study of 144 autistic male subjects, 18 were found to have the fragile X chromosome, supporting other (epidemiological) findings that the association between fragile X and autism occurs relatively frequently.