The figure displays the map of the deletions in chromosomal band 1q44 identified by aCGH. Black horizontal bars indicate the deletions in the 11 patients with ID and seizures. The vertical region shaded in red indicates the smallest region of overlap (SRO) implicated in ID and seizures; yellow indicates the SRO implicated in microcephaly and blue, the SRO implicated in corpus callosum abnormalities. B. Detailed map of the proposed critical region for ID and seizures, which contains three candidate genes: HNRNPU, FAM36A and NCRNA00201. See article by Thierry et al. in this issue.