Cognitive profiles of 42 Italian school-age children with Duchenne muscular dystrophy were studied in relation to the site of mutations along the dystrophin gene, distal vs proximal, involving or sparing the expression of Dp140, respectively. Full-scale IQ was a mean of 86.43 +/- 13.7 and 1 SD below the population average in the total group. Patients with distal located mutations were more severely affected compared to patients with proximal located mutations (not involving Dp140). Duchenne dystrophy patients with distal mutations had specific impairments in visuospatial functions and visual memory and greater impairment in syntactic sentence processing. 
COMMENT. Children with Duchenne muscular dystrophy are intellectually impaired, with greater deficits in verbal compared to visuospatial cognition. Those with distal mutations on the dystrophin gene, involving Dp140 isoform, are most severely impaired intellectually.