X-linked lissencephaly with absent corpus callosum and ambiguous genitalia.

Lissencephaly has been described in over 10 distinct malformation syndromes. Recently, we have recognized 5 children from four unrelated families with an almost identical disorder comprising lissencephaly with a posterior-to-anterior gradient and only moderate increase in thickness of the cortex, absent corpus callosum, neonatal-onset epilepsy, hypothalamic dysfunction including deficient temperature regulation, and ambiguous genitalia in genotypic males. Our observation of 5 affected males in one of these families is consistent with an X-linked pattern of inheritance. However, it differs in many regards from the X-linked form of isolated lissencephaly sequence that is associated with mutations of the XLIS (DCX) gene. Therefore, we propose that this disorder comprises a new X-linked malformation syndrome, which we refer to as X-linked lissencephaly with ambiguous genitalia (XLA-G).