Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a complex disease with a strong genetic component. More than 40 loci have been identified to be associated with the risk of NSCL/P by genome-wide association studies (GWASs), but the majority of these variants are mapped to non-coding regions of the genome. Expression quantitative trait locus (eQTL) studies have increasingly been integrated with GWASs to identify target genes for these non-coding variants. In this study, we generated a unique, lip-specific eQTL dataset from 40 NSCL/P patients. A total of 5158 eQTL SNPs (eSNPs) -689 eQTL genes were identified after multiple corrections. Then, we integrated nominal eQTL SNPs with NSCL/P risk SNPs and identified 243 variants associated with the expression of 18 genes in lip tissues. Functional annotation analysis indicated that these risk eSNPs were significantly enriched in transcription regulation and chromatin open regions on the genome. These susceptible genes were enriched in cell fate determination, the pluripotency of stem cells, and Wnt signaling pathways. Finally, 8 of the 18 susceptible genes were differentially expressed in NSCL/P case-control studies. In summary, we have generated a unique lip-specific eQTL resource and identified multiple associations for NSCL/P risk loci, which should inform functional studies of NSCL/P biology.

Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is a common craniofacial birth defect with complex etiologies. Recently, the dysregulation of long noncoding RNAs (lncRNAs) has been implicated in many developmental diseases, including NSCL/P. However, the functions and mechanisms of lncRNAs in NSCL/P have not been fully elucidated. In this study, we found that lncRNA MIR31HG in NSCL/P patients was significantly downregulated than that in healthy individuals (GSE42589, GSE183527). In addition, single nucleotide polymorphism rs58751040 in MIR31HG was nominally associated with NSCL/P susceptibility (odds ratio: 1.29, 95% confidence interval: 1.03–1.54, p = 4.93 × 10 ⁻² ) through a case–control study (504 NSCL/P cases and 455 controls). Luciferase activity assay showed that the C allele of rs58751040 revealed a decreased transcription activity of MIR31HG than the G allele. Moreover, knockdown of MIR31HG promoted cell proliferation and migration in human oral keratinocytes and human embryonic palate mesenchyme. Bioinformatic analysis and cellular studies suggested that MIR31HG may confer susceptibility to risk of NSCL/P through matrix Gla protein ( MGP ) signaling. In summary, we identified a novel lncRNA involved in the development of NSCL/P.