Etiology of intellectual impairment in Duchenne muscular dystrophy.

The precise etiology of intellectual impairment in Duchenne muscular dystrophy (DMD) is unknown. Histopathologic and computed tomographic studies have revealed structural brain changes; however, to our knowledge, no cranial magnetic resonance imaging (MRI) studies have been performed on DMD patients to further delineate these structural changes. We prospectively studied 4 DMD patients by cranial MRI, DNA deletion analysis, clinical evaluation, and intelligence testing. There was no significant correlation between verbal intelligence scores and MRI findings, DNA deletion, or the clinical severity of the disease. These first MRI studies of DMD did not reveal any significant anatomic brain alteration, other than mild atrophy in 2 patients. We believe these results must be considered when investigating the etiology of intellectual impairment in DMD in future studies with larger patient samples.