A number of schizencephaly patients including 2 brothers are heterozygous for germline mutations in the homeobox gene EMX2.

We report here that some patients affected by schizencephaly are heterozygous for mutations in EMX2, a homeobox gene implicated in the patterning of the developing forebrain. Schizencephaly is a very rare human congenital disorder characterized by a full-thickness cleft within the cerebral hemispheres. Large portions of these may be absent and replaced by cerebrospinal fluid. We previously reported the presence of EMX2 mutations in 7 out of 8 sporadic cases of schizencephaly. We now extend this analysis to 10 additional patients, including 2 brothers. Six patients were found to be heterozygous for de novo mutations in EMX2. In particular, the 2 brothers show the same mutation affecting the splicing of the first intron, while this mutation is absent in their parents and in the 2 unaffected siblings.