Axonal involvement with white matter abnormalities in merosin-positive congenital muscular dystrophy: A new association

An 18-month-old infant who presented with delayed motor development, hypotonia and absent deep tendon reflexes and normal cognitive development was diagnosed to have merosin-positive congenital muscular dystrophy (MP-CMD) on the basis of raised serum levels of creatine kinase, features suggestive of myopathy on electrophysiological studies, dystrophic muscle pathology and normal immunohistochemistry for merosin (laminin- α 2). Neuroimaging studies demonstrated white matter hyperintensities on T 2 -weighted images similar to that seen in patients with merosin negative (MN-CMD). Electrophysiological studies also demonstrated features of axonal involvement. This finding has not been previously described in association with MP-CMD. Although we have not been able to exclude abnormal glycosylation of α -dystroglycan, this case expands the clinical phenotype of MP-CMD and suggests that neuroimaging of children with CMD may be useful in the identification of variants of MP-CMD.