Second, five of the eight cognitive function genes (KDM5B (ref. 12,13) (MIM 618109), ANKRD12 (ref. 30), CACNA1A (MIM 183086, MIM 108500 and MIM 617106), GIGYF1 (refs. 12,13) and BCAS3 (MIM 619641)) are either established Mendelian DD genes or have also been identified in previous exome studies on SCZ30,51, DD13 or ASD12. The gene discussed is KDM5B; the disease is dentin dysplasia.