The classical thick lissencephaly appearance with P > A gradient and prominent cell-sparse zone seen in the CAMSAP1-related neuronal migration disorder is analogous to the findings seen in PAFAH1B1(LIS1)-related lissencephaly3 and thus predictive of a four-layer cortical histopathology. The gene discussed is PAFAH1B1; the disease is Abnormality of neuronal migration.