WHAT IS ASSOCIATED WITH THE FRAGILE-X SYNDROME

In addition to mental retardation (MR), fragile X [fra(X)] syndrome ha s been associated with a variety of other disorders. Despite earlier r eports, it has been shown that MR fra(X) males are at no greater risk for autism than is any MR male. Therefore, studies in which fra(X) has been associated with behavioral, developmental, and psychopathologica l disabilities were examined to determine whether fra(X) individuals w ere at an increased risk for these dysfunctions as well. Psychiatric d isorders among fra(X) individuals were found not to occur more frequen tly than in other individuals with cognitive deficits. It was also obs erved that hyperactivity and attention deficit disorder among MR fra(X ) individuals do not occur more frequently than in other MR individual s. Pooled results from studies of cognitive profiles used to character ize fra(X) phenotypes also indicated that there are no consistent patt erns in either males or females. Plausible explanations for a variable phenotype include allelic heterogeneity and pleitropy. (C) 1993 Wiley -Liss, Inc.