OBJECTIVE: To explore the genetic characteristics of a Chinese pedigree affected with van der Woude syndrome (VWS). METHODS: A proband who had visited the Drum Tower Hospital Affiliated to Nanjing University Medical School in May 2020 for "two previous pregnancies with cleft lip and palate" was selected as the study subject. Trio-whole exome sequencing (trio-WES) was carried out for the patient. Candidate variants were verified by Sanger sequencing of her pedigree members (8 individuals from four generations) and bioinformatic analysis. Chromosomal microarray analysis (CMA) was used to rule out copy number variations in the fetuses. RESULTS: Trio-WES revealed that the proband and her father had both harbored a heterozygous c.742G>T (p.G248C) missense variant of the IRF6 gene, for which her mother was of the wild type. The variant was located in a region with important functions and has not been reported previously. Prediction with several software suggested that it is likely to have a significant impact on the protein structure/function and is highly correlated with the specific phenotypes in this pedigree. Sanger sequencing confirmed co-segregation of the genotypes and phenotypes in the pedigree. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), this variant was rated as likely pathogenic (PM1+PM2_Supporting+PP1+PP3+PP4). Based on the above results, pre-implantation genetic diagnosis was carried out for the proband, which has led to birth of a healthy offspring with normal results for both site testing and CMA. CONCLUSION The IRF6: c.742G>T (p.G248C) heterozygous variant probably underlay the VWS in this pedigree. Above finding has also enabled reproductive guidance for the proband.
Humans ; Female ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; Pedigree ; DNA Copy Number Variations ; East Asian People ; Interferon Regulatory Factors/genetics* ; Mutation

The cranial neural crest plays a fundamental role in orofacial development and morphogenesis. Accordingly, mutations with impact on the cranial neural crest and its development lead to orofacial malformations such as cleft lip and palate. As a pluripotent and dynamic cell population, the cranial neural crest undergoes vast transcriptional and epigenomic alterations throughout the formation of facial structures pointing to an essential role of factors regulating chromatin state or transcription levels. Using CRISPR/Cas9-guided genome editing and conditional mutagenesis in the mouse, we here show that inactivation of Kat5 or Ep400 as the two essential enzymatic subunits of the Tip60/Ep400 chromatin remodeling complex severely affects carbohydrate and amino acid metabolism in cranial neural crest cells. The resulting decrease in protein synthesis, proliferation and survival leads to a drastic reduction of cranial neural crest cells early in fetal development and a loss of most facial structures in the absence of either protein. Following heterozygous loss of Kat5 in neural crest cells palatogenesis was impaired. These findings point to a decisive role of the Tip60/Ep400 chromatin remodeling complex in facial morphogenesis and lead us to conclude that the orofacial clefting observed in patients with heterozygous KAT5 missense mutations is at least in part due to disturbances in the cranial neural crest.
Animals ; Mice ; Chromatin Assembly and Disassembly ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; DNA Helicases/metabolism* ; DNA-Binding Proteins ; Neural Crest/metabolism* ; Skull ; Transcription Factors/metabolism*

Non-syndromic oral cleft (NSOC), a common birth defect, remains to be a critical public health problem in China. In the context of adjustment of childbearing policy for two times in China and the increase of pregnancy at older childbearing age, NSOC risk prediction will provide evidence for high-risk population identification and prenatal counseling. Genome-wide association study and second generation sequencing have identified multiple loci associated with NSOC, facilitating the development of genetic risk prediction of NSOC. Despite the marked progress, risk prediction models of NSOC still faces multiple challenges. This paper summarizes the recent progress in research of NSOC risk prediction models based on the results of extensive literature retrieval to provide some insights for the model development regarding research design, variable selection, model-build strategy and evaluation methods.
Humans ; Cleft Palate/genetics* ; Cleft Lip/genetics* ; Genome-Wide Association Study ; Genetic Predisposition to Disease ; Risk Factors ; Polymorphism, Single Nucleotide

Genome-wide association studies (GWASs) are the most widely used method to identify genetic risk loci associated with orofacial clefts (OFC). However, despite the increasing size of cohort, GWASs are still insufficient to detect all the heritability, suggesting there are more associations under the current stringent statistical threshold. In this study, we obtained an integrated epigenomic dataset based on the chromatin conformation of a human oral epithelial cell line (HIOEC) using RNA-seq, ATAC-seq, H3K27ac ChIP-seq, and DLO Hi-C. Presumably, this epigenomic dataset could reveal the missing functional variants located in the oral epithelial cell active enhancers/promoters along with their risk target genes, despite relatively less-stringent statistical association with OFC. Taken a non-syndromic cleft palate only (NSCPO) GWAS data of the Chinese Han population as an example, 3664 SNPs that cannot reach the strict significance threshold were subjected to this functional identification pipeline. In total, 254 potential risk SNPs residing in active cis-regulatory elements interacting with 1 718 promoters of oral epithelium-expressed genes were screened. Gapped k-mer machine learning based on enhancers interacting with epithelium-expressed genes along with in vivo and in vitro reporter assays were employed as functional validation. Among all the potential SNPs, we chose and confirmed that the risk alleles of rs560789 and rs174570 reduced the epithelial-specific enhancer activity by preventing the binding of transcription factors related to epithelial development. In summary, we established chromatin conformation datasets of human oral epithelial cells and provided a framework for testing and understanding how regulatory variants impart risk for clefts.
Chromatin ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; Epithelium ; Genome-Wide Association Study ; Humans

OBJECTIVE: To explore the association between de novo mutations (DNM) and non-syndromic cleft lip with or without palate (NSCL/P) using case-parent trio design. METHODS: Whole-exome sequencing was conducted for twenty-two NSCL/P trios and Genome Analysis ToolKit (GATK) was used to identify DNM by comparing the alleles of the cases and their parents. Information of predictable functions was annotated to the locus with SnpEff. Enrichment analysis for DNM was conducted to test the difference between the actual number and the expected number of DNM, and to explore whether there were genes with more DNM than expected. NSCL/P-related genes indicated by previous studies with solid evidence were selected by literature reviewing. Protein-protein interactions analysis was conducted among the genes with protein-altering DNM and NSCL/P-related genes. R package "denovolyzeR" was used for the enrichment analysis (Bonferroni correction: P=0.05/n, n is the number of genes in the whole genome range). Protein-protein interactions among genes with DNM and genes with solid evidence on the risk factors of NSCL/P were predicted depending on the information provided by STRING database. RESULTS: A total of 339 908 SNPs were qualified for the subsequent analysis after quality control. The number of high confident DNM identified by GATK was 345. Among those DNM, forty-four DNM were missense mutations, one DNM was nonsense mutation, two DNM were splicing site mutations, twenty DNM were synonymous mutations and others were located in intron or intergenic regions. The results of enrichment analysis showed that the number of protein-altering DNM on the exome regions was larger than expected (P < 0.05), and five genes (KRTCAP2, HMCN2, ANKRD36C, ADGRL2 and DIPK2A) had more DNM than expected (P < 0.05/(2×19 618)). Protein-protein interaction analysis was conducted among forty-six genes with protein-altering DNM and thirteen genes associated with NSCL/P selected by literature reviewing. Six pairs of interactions occurred between the genes with DNM and known NSCL/P-related genes. The score measuring the confidence level of the predicted interaction between RGPD4 and SUMO1 was 0.868, which was higher than the scores for other pairs of genes. CONCLUSION Our study provided novel insights into the development of NSCL/P and demonstrated that functional analyses of genes carrying DNM were warranted to understand the genetic architecture of complex diseases.
Asians ; Case-Control Studies ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; Genetic Predisposition to Disease ; Genome-Wide Association Study ; Genotype ; Humans ; Mutation ; Parents ; Polymorphism, Single Nucleotide ; Whole Exome Sequencing

OBJECTIVE: To explore whether WNT signaling pathway genes were associated with non-syndromic oral clefts (NSOC) based on haplotypes analyses among 1 008 Chinese NSOC case-parent trios. METHODS: The genome-wide association study (GWAS) data of 806 Chinese non-syndromic cleft lip with or without cleft palate (NSCL/P) trios and 202 Chinese non-syndromic cleft palate (NSCP) case-parent trios were drawn from the International Consortium to Identify Genes and Interactions Controlling Oral Clefts (ICOCs) study GWAS data set, whose Chinese study population were recruited from four provinces in China, namely Taiwan, Shandong, Hubei, and Sichuan provinces. The process of DNA genotyping was conducted by the Center for Inherited Disease Research in the Johns Hopkins University, using Illumina Human610-Quad v.1_B Bead Chip. The method of sliding windows was used to determine the haplotypes for analyses, including 2 SNPs haplotypes and 3 SNPs haplotypes. Haplotypes with a frequency lower than 1% were excluded for further analyses. To further assess the association between haplotypes and NSOC risks, and the transmission disequilibrium test (TDT) was performed. The Bonferroni method was adopted to correct multiple tests in the study, with which the threshold of statistical significance level was set as P < 0.05 divided by the number of tests, e.g P < 3.47×10^-4 in the current stu-dy. All the statistical analyses were performed by using plink (v1.07). RESULTS: After quality control, a total of 144 single nucleotide polymorphisms (SNPs) mapped in seven genes in WNT signaling pathway were included for the analyses among the 806 Chinese NSCL/P trios and 202 Chinese NSCP trios. A total of 1 042 haplotypes with frequency higher than 1% were included for NSCL/P analyses and another 1 057 haplotypes with frequency higher than 1% were included for NSCP analyses. Results from the TDT analyses showed that a total of 69 haplotypes were nominally associated with the NSCL/P risk among Chinese (P < 0.05). Another 34 haplotypes showed nominal significant association with the NSCP risk among Chinese (P < 0.05). However, none of these haplotypes reached pre-defined statistical significance level after Bonferroni correction (P>3.47×10^-4). CONCLUSION This study failed to observe any statistically significant associations between haplotypes of seven WNT signaling pathway genes and the risk of NSOC among Chinese. Further studies are warranted to replicate the findings here.
Cleft Lip/genetics* ; Cleft Palate/genetics* ; Genetic Predisposition to Disease ; Genome-Wide Association Study ; Genotype ; Haplotypes ; Humans ; Polymorphism, Single Nucleotide ; Wnt Signaling Pathway/genetics*

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with non-syndromic cleft lip and cleft palate (NSCLP). METHODS: With informed consent obtained, members of the pedigree were subjected to clinical examination and history taking to exclude syndromic cleft lip and palate. One affected member was subjected to whole-exome sequencing and bioinformatics analysis. Candidate variant was verified by Sanger sequencing and co-segregation analysis of her family members and 100 unrelated healthy individuals. RESULTS: Whole-exome sequencing and co-segregation analysis showed that all affected members of this pedigree have carried a heterozygous missense c.253A>G (p.Cys85Arg) variant in exon 4 of the IRF6 gene, which has co-segregated with the phenotype and was not found among the 100 unrelated healthy individuals. CONCLUSION The missense c.253A>G variant in exon 4 of the IRF6 gene probably underlay the NSCLP in this pedigree.
Brain/abnormalities* ; China ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; Female ; Humans ; Interferon Regulatory Factors/genetics* ; Mutation, Missense ; Pedigree ; Whole Exome Sequencing

OBJECTIVE: To explore the genetic etiology for a fetus with congenital orofacial cleft. METHODS: Single nucleotide polymorphism microarray (SNP array) was carried out on skin tissues sampled from the fetus following induced abortion for the detection of copy number variation (CNVs). Pathogenicity of the candidate gene was validated through experiment. RESULTS: SNP array revealed that the fetus has carried a hemizygous 9.23Mb deletion at Xq21.31-q22.1(91 063 807-100 293 555), which was inherited from its mother. The region contained 13 OMIM genes and 1 ncRNA coding gene(MIR548M). Inhibiting of the expression of the MIR548M gene in oral epithelial celllines has resulted in up-regulation of the expression of SUMO1 gene which was known to involve in the pathogenesis of orofacial cleft. CONCLUSION Dosage insufficiency of the MIR548M gene may underlie the etiology of orofacial cleft in this fetus.
Cleft Lip/genetics* ; Cleft Palate/genetics* ; DNA Copy Number Variations/genetics* ; Female ; Fetus ; Humans ; MicroRNAs/genetics* ; Polymorphism, Single Nucleotide ; Pregnancy ; SUMO-1 Protein

OBJECTIVE: To explore the genetic basis for a fetus with cleft lip and palate. METHODS: Copy number variations (CNVs) in the fetus and his parents were detected with chromosomal microarray analysis (CMA). RESULTS: As revealed by the CMA assay, the fetus has carried a 228 kb deletion in Xp11.22 region and a 721 kb duplication in 9p21.1. Both CNVs were inherited from the parents. The CNV in Xp11.22 was predicted to be pathogenic by involving the PHF8 gene, whilst the CNV in 9p21.1 was predicted to be benign. CONCLUSION Deletion of the Xp11.22 region probably underlies the cleft lip and palate in this fetus.
Chromosome Deletion ; Chromosomes, Human, X ; genetics ; Cleft Lip ; diagnosis ; genetics ; Cleft Palate ; diagnosis ; genetics ; DNA Copy Number Variations ; Female ; Fetus ; Histone Demethylases ; Humans ; Microarray Analysis ; methods ; Pregnancy ; Prenatal Diagnosis ; Transcription Factors

OBJECTIVE: Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common birth defect, affecting 1.4 per 1 000 live births, and multiple genetic and environmental risk factors influencing its risk. All the known genetic risk factors accounted for a small proportion of the heritability. Several authors have suggested parent-of-origin effects (PoO) may play an important role in the etiology of this complex and heterogeneous malformation. To clarify the genetic association between PTCH1, PTCH2, SHH and SMO in hedgehog (HH) pathway and NSCL/P, as well as testing for potential PoO effects in Chinese case-parent trios. METHODS: We tested for transmission disequilibrium tests (TDT) and PoO effects using 83 common single nucleotide polymorphic (SNP) markers of HH pathway genes from 806 NSCL/P case-parent trios. These trios were drawn from an international consortium established for a genome-wide association studies (GWAS) of non-syndromic oral clefts of multiple ethnicities. DNA samples were collected from each trio. Single marker and haplotype based analysis were performed both in TDT tests and PoO effects. SNPs were excluded if they (ⅰ) had a call rate of < 95%, (ⅱ) had a minor allele frequency (MAF) of < 0.05, (ⅲ) had Mendelian errors over all trios of >5%, (ⅳ) had a genotype distribution in the parents that deviated from the Hardy-Weinberg equilibrium (HWE) (P < 0.000 1). The process was done using Plink (version 1.07, http://pngu.mgh.harvard.edu/~purcell/plink/data.shtml). TDT test was performed in Plink v1.07. A log-linear model was used to explore PoO effects using Haplin v6.2.1 as implemented in R package v3.4.2. Significance level was assessed using the Bonferroni correction. RESULTS: A total of 18 SNPs were dropped due to low MAF, thus leaving 65 SNPs available for the analysis. Thus the Bonferroni threshold was 7.7×10^-4 (0.05/65). Nominal significant association with NSCL/P was found at a SNP (rs4448343 in PTCH1, P=0.023) and six haplotypes (rs10512249-rs4448343, rs1461208-rs7786445, rs10512249-rs4448343, rs16909865-rs10512249-rs4448343, rs1461208-rs7786445-rs12698335, and rs288756-rs288758-rs1151790, P < 0.05). A total of six haplotypes (rs288765-rs1233563, rs12537550-rs11765352, rs872723-rs288765-rs1233563, rs288765-rs1233563-rs288756, rs6459952-rs12537550-rs11765352, and rs12537550-rs11765352-rs6971211) showed PoO effect (P < 0.05). None of the results remained significant after the Bonferroni correction (P>7.7×10^-4). CONCLUSION Neither significant association between SNPs within HH pathway and the risk of NSCL/P nor PoO effects was seen in this study.
Asians ; Cleft Lip/genetics* ; Cleft Palate/genetics* ; Genome-Wide Association Study ; Hedgehog Proteins/genetics* ; Humans ; Patched-2 Receptor ; Smoothened Receptor