IRF6 and cleft lip: In addition to IRF6, v-maf musculoaponeurotic fibrosarcoma oncogene homolog B (MAFB) and intron 6 of the ATP-binding cassette subfamily A member 4 (ABCA4) also contribute to the risk of cleft lip and palate (Mossey et al., 2009; Beaty et al., 2010; Huang et al., 2012).