Whereas LIS1 mutations generally manifest as classical lissencephaly (lissencephaly-1), characterized by disorganized lamination of the cortex without microcephaly, NDE1 encephalopathy presents itself as extreme brain atrophy that includes microcephaly and lissencephaly (lissencephaly-4) (Saillour et al., 2009). This evidence concerns the gene PAFAH1B1 and lissencephaly spectrum disorders.