Neuropsychological profiles of FMR-1 premutation and full-mutation carrierfemales

The present French-German investigation of fragile-X syndrome (fra-X) was u ndertaken to disentangle genetic from environmental effects on cognitive pe rformance as assessed with the following measures: Wechsler Adult Intellige nce Scale-Revised (WAIS-R), Wisconsin Card Sorting Test, Trail-Making Test, Tower of Hanai, Verbal Fluency Test, Stroop Test, short-term and consolida tion memory, and the d2 task. Groups with different genotypes (n = 11 mothe rs with a full mutation in the FMR-1 gene of fra-X children; n = 65 mothers with a premutation in the FMR-1 gene of fra-X children; n=18 siblings of t hese mothers with normal CGG repeats) and with different psychosocial stres sors from fra-X families (n = 14 siblings with a premutation but without af fected children of their own) were examined. A group of mothers of non-fra- X autistic children (n = 39) formed an external control group. Previous fin dings were replicated concerning cognitive performance of FMR-1 full-mutati on carrier mothers, who were characterized by lower overall IQ and poorer p erformance than the group of mothers with the FMR-1 premutation in verbal a nd performance subtests of the WAIS-R, tests of executive-frontal lobe func tioning, and tests of sustained attention. Carriers of the FMR-1 premutatio n, whether they were mothers of affected children or not, performed in a si milar way on all neuropsychological tasks to the intrafamilial control grou p without CGG amplification. On the basis of these results, it is concluded that there is no neuropsychological evidence of reduced cognitive performa nce of FMR-1 premutation carriers compared with performance of two control groups with normal CGG repeats. Furthermore, the psychosocial burden of rai sing fra-X children does not exert an environmental effect on neuropsycholo gical test performance. (C) 1999 Elsevier Science Ireland Ltd. All rights r eserved.