IRF6 and orofacial cleft: We selected 18 nonsyndromic orofacial cleft-related candidate genes, including ABCA4, BMP4, CRISPLD2, GSTT1, FGF8, FGFR2, FOXE1, IRF6, MAFB, MSX1, MTHFR, MYH9, PDGFC, PVRL1, SUMO1, TGFA, TGFB3, and VAX1, based on previous associated studies [7, 17] to conduct a customized NGS panel and subsequently manipulated a whole-exon targeted-sequencing study based on the NGS system of an Ion Torrent Personal Genome Machine (IT-PGM).