COL4A1 and polymicrogyria: The most typical is through predisposition to hemorrhagic and ischemic insults, as demonstrated by mouse models.3,4 MCD were also associated with Col4a1 mutations, as a result of defects of cortical lamination.44 Here, we found a notably high prevalence (28.9% of new cases) of polymicrogyria, schizencephaly, or focal cortical dysplasia.