Pathogenic variants in MLL3 were identified in large whole exon sequencing studies in patients with ASD (De Rubeis et al., 2014; Iossifov et al., 2014), and have been associated with an ID/ASD related syndrome that presents microcephaly in 50% of the cases reported (Koemans et al., 2017). The gene discussed is KMT2C; the disease is microcephaly.