DCX and lissencephaly spectrum disorders: The primary pathology of lissencephaly due to the DCX mutations shows only minor differences compared with that caused by LIS1 mutations, for example, inferior olivary ectopia is present in LIS1 mutation brains but is absent in DCX mutation brain (Berg et al., 1998); however, Viot et al. report a different cortical architecture for DCX lissencephaly (Viot et al., 2004).