Target Capture/Next-Generation Sequencing for Nonsyndromic Cleft Lip and Palate in the Japanese Population.

OBJECTIVE: The pathogenesis of nonsyndromic cleft lip with or without cleft palate (NSCL ± P) and nonsyndromic cleft palate only (NSCP) may be associated with genetic factors. Although some predisposing genes/loci have been reported, their attributable risk is too small to be clinically meaningful. To clarify the genetic causes and mechanisms of NSCL±P or NSCP, we conducted mutation analysis of target genes using a next-generation sequencing (NGS) approach.

METHODS: The target genes, IRF6, WNT5A, WNT9B, TP63, MSX1, TFAP2A, PAX9, DLX3, DLX4, and MN1, were selected based on previous reports of potential associations with the development of NSCL±P or NSCP from genome-wide association studies and candidate gene analyses. Mutation analysis was conducted using NGS on 74 Japanese trios (patient and parents) and 18 Japanese patients only families.

RESULTS: We detected single-nucleotide variants (SNVs) for 7 genes: IRF6, DLX4, WNT5A, TFAP2A, WNT9B, TP63, and PAX9. The SNVs found on IRF6 and DLX4 were missense mutations, whereas those identified on WNT5A, TFAP2A, WNT9B, TP63, and PAX9 were rare variants in the noncoding region; no de novo mutation was identified in the trio samples. The amino acid change on DLX4 was detected within the highly conserved homeodomain and was predicted to have a deleterious impact on the protein function by in silico analysis.

CONCLUSIONS: The DLX4 missense mutation c.359C>T (Pro120Leu) was found in 1 Japanese patient with NSCL±P and was located in the homeodomain region. This mutation likely plays a role in the development of NSCL±P in the Japanese population.