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BACKGROUND AND PURPOSE: Duchenne muscular dystrophy is an X-linked disorder characterized by progressive muscle weakness and prominent nonmotor manifestations, such as a low intelligence quotient and neuropsychiatric disturbance. We investigated WM integrity in patients with Duchenne muscular dystrophy using DTI. MATERIALS AND METHODS:Fractional anisotropy and mean, axial, and radial diffusivity (DTI measures) were used to assess WM microstructural integrity along with neuropsychological evaluation in patients with Duchenne muscular dystrophy (n ¼ 60) and controls (n ¼ 40). Exon deletions in the DMD gene were confirmed using multiplex ligation-dependent probe amplification. Patients were classified into proximal (DMD Dp1401) and distal (DMD Dp140-) subgroups based on the location of the exon deletion and expression of short dystrophin Dp140 isoform. WM integrity was examined using whole-brain Tract-Based Spatial Statistics and atlas-based analysis of DTI data. The Pearson correlation was performed to investigate the possible relationship between neuropsychological scores and DTI metrics. RESULTS:The mean ages of Duchenne muscular dystrophy and control participants were 8.0 6 1.2 years and 8.2 6 1.4 years, respectively. The mean age at disease onset was 4.1 6 1.8 years, and mean illness duration was 40.8 6 25.2 months. Significant differences in neuropsychological scores were observed between the proximal and distal gene-deletion subgroups, with more severe impairment in the distal-deletion subgroup (P , .05). Localized fractional anisotropy changes were seen in the corpus callosum, parietal WM, and fornices in the patient subgroup with Dp1401, while widespread changes were noted in the Dp140-subgroup. The Dp1401 subgroup showed increased axial diffusivity in multiple WM regions relative to the Dp140-subgroup. No significant correlation was observed between clinical and neuropsychological scores and diffusion metrics.CONCLUSIONS: Widespread WM differences are evident in patients with Duchenne muscular dystrophy relative to healthy controls. Distal mutations in particular are associated with extensive WM abnormalities and poor neuropsychological profiles.

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