Mutations in LARGE1 cause Congenital Muscular Dystrophy Type 1D (MDC1D), which can present with cognitive deficits that are accompanied by structural brain abnormalities including abnormal white matter and neuronal migration defects that manifest as “cobblestone” ectopias (Longman et al., 2003; Montanaro and Carbonetto, 2003). This evidence concerns the gene LARGE1 and muscular dystrophy-dystroglycanopathy type B6.