The 49,XXXXY syndrome: clinical and psychological findings in five patients.

In this study clinical and psychological findings are presented in five 49,XXXXY patients. Their degree of mental retardation varied greatly, i.e. from moderately to profoundly retarded. A decline in intelligence performance with age was observed in one boy. Language development was severely retarded with a remarkable discrepancy between language expression and comprehension. Emotional disturbances with low frustration level, timidity and shyness were noted in all five and their level of adaptive functioning was much higher than the cognitive level.