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Although several genome‐wide association studies (GWAS) of non‐syndromic cleft lip with or without cleft palate (NSCL/P) have been reported, more novel association signals are remained to be exploited. Here, we performed an in‐depth analysis of our previously published Chinese GWAS cohort study with replication in an extra dbGaP case‐parent trios and another in‐house Nanjing cohort, and finally identified five novel significant association signals (rs11119445: 3' of SERTAD4, P = 6.44 × 10−14; rs227227 and rs12561877: intron of SYT14, P = 5.02 × 10−13 and 2.80 × 10−11, respectively; rs643118: intron of TRAF3IP3, P = 4.45 × 10−6; rs2095293: intron of NR6A1, P = 2.98 × 10−5). The mean (standard deviation) of the weighted genetic risk score (wGRS) from these SNPs was 1.83 (0.65) for NSCL/P cases and 1.58 (0.68) for controls, respectively (P = 2.67 × 10−16). Rs643118 was identified as a shared susceptible factor of NSCL/P among Asians and Europeans, while rs227227 may contribute to the risk of NSCL/P as well as NSCPO. In addition, sertad4 knockdown zebrafish models resulted in down‐regulation of sox2 and caused oedema around the heart and mandibular deficiency, compared with control embryos. Taken together, this study has improved our understanding of the genetic susceptibility to NSCL/P and provided further clues to its aetiology in the Chinese population. [ABSTRACT FROM AUTHOR]

Background The axis inhibition protein 2 ( AXIN2) is an important regulator of β-catenin degradation in the Wnt pathway, which plays a key role in craniofacial morphogenesis. The goal of this study was to investigate the potential relationship between AXIN2 polymorphisms and the risks of non-syndromic orofacial clefts ( NSOC) in a Chinese Han population. Methods Four polymorphisms of AXIN2 (rs2240307, rs11867417, rs2240308, and rs7591) were selected to perform a case-control study with 599 NSOC cases and 602 healthy individuals from a Chinese Han population. The single nucleotide polymorphisms ( SNPs) were genotyped on basis of double ligation and multiplex fluorescence PCR. Results Weak associations were found between these four SNPs and the risk of NSOC. Further stratified analysis showed that the overall genotype frequencies of rs2240307 were different between the cleft palate only ( CPO) group and the control group ( P = 0.048), and GG genotype markedly contributed to the susceptibility to CPO ( OR = 3.22, 95% CI = 1.13-9.18). The similar effect was also observed on GA/ AA genotype compared with GG homozygote ( OR = 0.30, 95% CI = 0.11-0.84). The results of LD analysis between each pair of SNPs revealed that two SNPs (rs11867417 and rs7591) were in a LD block ( r2 > 0.8). But no statistically significant was found between cases and controls from haplotype analysis in these two loci. Conclusions The borderline results gave us a hint that rs2240307 contributed to the susceptibility to CPO in a Chinese Han population, which was conductive to improving our awareness of the causes of NSOC. [ABSTRACT FROM AUTHOR]

Cleft lip with or without cleft palate (CL/P) is one of the most common birth defects worldwide and is characterized by abnormalities of the orofacial structure. Syndromic CL/P is mainly caused by Mendelian disorders such as Van der Woude Syndrome (VWS). However, > 70% of CL/P cases are nonsyndromic, characterized by isolated orofacial cleft without any known syndrome. The etiology of nonsyndromic CL/P (NSCL/P) remains elusive, but it has been suggested that causative genes of syndromic CL/P might also contribute to NSCL/P. As such, the VWS causative gene IRF6 has been extensively studied in NSCL/P. Recently, GRHL3 was identified as another VWS causative gene. Thus, it may be a novel candidate gene for NSCL/P. In the present study, we genotyped 10 tag SNPs covering GRHL3 and performed association analysis with NSCL/P in 504 cases and 455 healthy controls. Our preliminary results identified rs10903078, rs4638975, and a haplotype rs10903078-rs6659209 of GRHL3 that exceeded the significance threshold (p < 0.05), though none survived Bonferroni correction for multiple comparisons. As the first study between GRHL3 and NSCL/P, the contribution of this gene to NSCL/P etiology should be interpreted with caution based on existing evidence. Further, the robustness of association between GRHL3 and NSCL/P should be further validated in expanded cohorts. [ABSTRACT FROM AUTHOR]