Identification of novel susceptibility loci for non-syndromic cleft lip with or without cleft palate.

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.

Non-syndromic cleft lip with or without palate-susceptible SNPs is associated with hyperdontia.

BACKGROUND: Non-syndromic supernumerary teeth (NSST) or hyperdontia may share common genetic determinants with non-syndromic cleft lip with or without palate (NSCL/P). The aim of this study was to test the associations between five genome-wide-associated NSCL/P-susceptible single nucleotide polymorphisms (SNPs) (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) and the occurrence of NSST. MATERIALS AND METHODS: A total of 163 cases and 326 controls were recruited and their genomic DNA was extracted from blood samples. Five NSCL/P-susceptible SNPs (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) were genotyped by TaqMan method. Odds ratio (OR) and 95% confidence interval (CI) were used to estimate the associations between the SNPs and the risk of NSST by PLINK software. RESULTS: Rs4791774 (A > G) and rs13041247 (T > C) were associated with risk of NSST (rs4791774: Padd  = 0.011, OR, 95% CI = 0.62, 0.43-0.90; rs13041247: Phomo  = 0.031, OR, 95% CI = 1.79, 1.05-3.05) and one supernumerary tooth (rs4791774: Pdom  = 0.009, OR, 95% CI = 0.56, 0.36-0.87; rs13041247: Phomo  = 0.034, OR, 95% CI = 1.82, 1.05-3.15). Rs4791774 (A > G) was also showed association with risk of upper arch supernumerary teeth only (Padd  = 0.010, OR, 95% CI = 0.60, 0.41-0.89). CONCLUSION: Non-syndromic cleft lip with or without palate-susceptible loci rs4791774 (A > G) and rs13041247 (T > C) were associated with the risk of supernumerary teeth.

Non-syndromic cleft lip with or without palate susceptible loci is associated with tooth agenesis.

OBJECTIVE: Non-syndromic tooth agenesis (NSTA) may share common genetic factors with non-syndromic cleft lip with or without cleft palate (NSCL/P). Single-nucleotide polymorphisms (SNPs) were associated with individual's susceptibility to these anomalies. We selected five NSCL/P-associated SNPs from our previous genome-wide association study (GWAS) to test for the associations with NSTA. MATERIALS AND METHODS: A total of 677 NSTA cases and 1,144 healthy controls were recruited in this case-control study. Five genome-wide NSCL/P-associated SNPs (rs2235371, rs7078160, rs8049367, rs4791774, and rs13041247) were genotyped by TaqMan platform and evaluated for the associations with NSTA using plink software. RESULTS: No significant associations between these SNPs and risk of NSTA were observed in the overall analysis and subgroup analysis with the number of missing teeth. However, in the subgroup analysis by tooth position, rs8049367 was nominally associated with mandibular premolar agenesis (Dominant model: ORdom  = 0.66, 95% CIdom  = 0.47-0.93, pdom  = 0.016; Heterozygote model: ORhet  = 0.60, 95% CIhet  = 0.41-0.88, Phet  = 0.008). Rs4791774 showed a nominal association with congenitally missing maxillary canine (Dominant model: ORdom  = 0.53, 95% CIdom  = 0.28-0.98, pdom  = 0.041; Heterozygote model: ORhet  = 0.50, 95% CIhet  = 0.26-0.97, Phet  = 0.041) and premolar (Additive model: OR = 0.59, 95% CI = 0.36-0.96, p = 0.035). CONCLUSION: This study showed that NSCL/P susceptible loci rs8049367 and rs4791774 were probably associated with the risk of NSTA.

METTL3-dependent m6A modification of PSEN1 mRNA regulates craniofacial development through the Wnt/ß-catenin signaling pathway.

Craniofacial malformations, often associated with syndromes, are prevalent birth defects. Emerging evidence underscores the importance of m6A modifications in various bioprocesses such as stem cell differentiation, tissue development, and tumorigenesis. Here, in vivo, experiments with zebrafish models revealed that mettl3-knockdown embryos at 144 h postfertilization exhibited aberrant craniofacial features, including altered mouth opening, jaw dimensions, ethmoid plate, tooth formation and hypoactive behavior. Similarly, low METTL3 expression inhibited the proliferation and migration of BMSCs, HEPM cells, and DPSCs. Loss of METTL3 led to reduced mRNA m6A methylation and PSEN1 expression, impacting craniofacial phenotypes. Co-injection of mettl3 or psen1 mRNA rescued the level of Sox10 fusion protein, promoted voluntary movement, and mitigated abnormal craniofacial phenotypes induced by mettl3 knockdown in zebrafish. Mechanistically, YTHDF1 enhanced the mRNA stability of m6A-modified PSEN1, while decreased METTL3-mediated m6A methylation hindered ß-catenin binding to PSEN1, suppressing Wnt/ß-catenin signaling. Pharmacological activation of the Wnt/ß-catenin pathway partially alleviated the phenotypes of mettl3 morphant and reversed the decreases in cell proliferation and migration induced by METTL3 silencing. This study elucidates the pivotal role of METTL3 in craniofacial development via the METTL3/YTHDF1/PSEN1/ß-catenin signaling axis.

Application of zebrafish in the study of craniomaxillofacial developmental anomalies.

Craniomaxillofacial developmental anomalies are one of the most prevalent congenital defects worldwide and could result from any disruption of normal development processes, which is generally influenced by interactions between genes and the environment. Currently, with the advances in genetic screening strategies, an increasing number of novel variants and their roles in orofacial diseases have been explored. Zebrafish is recognized as a powerful animal model, and its homologous genes and similar oral structure and development process provide an ideal platform for studying the contributions of genetic and environmental factors to human craniofacial malformations. Here, we reviewed zebrafish models for the study of craniomaxillofacial developmental anomalies, such as human nonsyndromic cleft lip with or without an affected palate and jaw and tooth developmental anomalies. Due to its potential for gene expression and regulation research, zebrafish may provide new perspectives for understanding craniomaxillofacial diseaseand its treatment.

Genetic Variants in miRNAs Are Associated With Risk of Non-syndromic Tooth Agenesis.

Non-syndromic tooth agenesis (NSTA) is one of the most common dental abnormalities. MiRNAs participated in the craniofacial and tooth development. Therefore, single nucleotide polymorphisms (SNPs) in miRNA genes may contribute to the susceptibility of non-syndromic tooth agenesis. Here, a total of 625 non-syndromic tooth agenesis cases and 1,144 healthy controls were recruited, and four miRNA SNPs (miR-146a/rs2910164, miR-196a2/rs11614913, pre-miR-605/rs2043556, pre-miR-618/rs2682818) were genotyped by the TaqMan platform. Rs2043556 showed nominal associations with risk of non-syndromic tooth agenesis (P Add = 0.021) in the overall analysis, as well as upper lateral incisor agenesis (P Add = 0.047) and lower incisor agenesis (P Add = 0.049) in the subgroup analysis. Notably, its significant association with upper canine agenesis was observed (P Add = 0.0016). Rs2043556 affected the mature of miR-605-3p and miR-605-5p while dual-luciferase report analysis indicated that MDM2 was the binding target of miR-605-5p. Our study indicated that pre-miR-605 rs2043556 was associated with risk of non-syndromic tooth agenesis.

Associations of the microRNA gene polymorphisms with the risk of non-syndromic supernumerary teeth in a Chinese population.

OBJECTIVE: Non-syndromic supernumerary teeth (NSST) are a common type of dental anomaly. microRNAs (miRNAs) play an important role in craniofacial and tooth development. Therefore, we hypothesized that single nucleotide polymorphisms (SNPs) of miRNAs may be associated with the susceptibility of NSST. MATERIALS AND METHODS: Four miRNA SNPs (rs2910164, rs11614913, rs2043556, and rs2682818) were selected, and their associations with NSST susceptibility were evaluated in a case-control study (163 NSST patients and 326 healthy controls). RESULTS: rs2910164 was significantly associated with a risk of lower NSST (additive model: OR = 4.00, 95 % CI = 1.76-9.09, P = 0.001), and rs2682818 showed nominal association with a risk of upper NSST (additive model: OR = 1.40, 95 % CI = 1.02-1.91, P = 0.037) and NSST among male patients (additive model: OR = 1.62, 95 % CI = 1.08-2.43, P = 0.020). CONCLUSION: Genetic variants of miR-146a/rs2910164 and miR-618/rs2682818 were likely associated with the risk of NSST in the Chinese population.