DCX and lissencephaly spectrum disorders: Mutations of the alpha tubulin 1A, LIS1 and doublecortin genes are all associated with classical forms of lissencephaly (Gleeson et al., 1998; Keays et al., 2007; Wynshaw-Boris, 2007), with LIS1 and DCX mutations causing different malformation gradients along the fronto-occipital axis (Pilz et al., 1999).