Contribution of polymorphisms in genes associated with craniofacial development to the risk of nonsyndromic cleft lip and/or palate in the Brazilian population

Background and Objective: Nonsyndromic cleft lip and/or palate (NSCL/P) is a complex disease associated with both genetic and environmental factors. One strategy for identifying of possible NSCL/P genetic causes is to evaluate polymorphic variants in genes involved in the craniofacial development. Design: We carried out a case-control analysis of 13 single nucleotide polymorphisms in 9 genes related to craniofacial development, including TBX1, PVRL1, MID1, RUNX2, TP63, TGF?3, MSX1, MYH9 and JAG2, in 367 patients with NSCL/P and 413 unaffected controls from Brazil to determine their association with NSCL/P. Results: Four out of 13 polymorphisms (rs28649236 and rs4819522 of TBX1, rs7940667 of PVRL1 and rs1057744 of JAG2) were presented in our population. Comparisons of allele and genotype frequencies revealed that the G variant allele and the AG/GG genotypes of TBX1 rs28649236 occurred in a frequency significantly higher in controls than in the NSCL/P group (OR: 0.41; 95% CI: 0.25-0.67; p=0.0002). The frequencies of rs4819522, rs7940667 and rs1057744 minor alleles and genotypes were similar between control and NSCL/P group, without significant differences. No significant associations among cleft types and polymorphisms were observed. Conclusion: The study suggests for the first time evidences to an association of the G allele of TBX1 rs28649236 polymorphism and NSCL/P. Key words:Cleft lip, cleft palate, polymorphism, genetic.     

VAX1 gene associated non-syndromic cleft lip with or without palate in Western Han Chinese

ObjectiveNon-syndromic cleft lip with or without palate (NSCL/P) is one of the most common human birth defects, it results from multiple genetic and environmental risk factors. Recently, GWA studies identified associations between NSCL/P and two genetic risk loci, rs7078160 and rs4752028, at VAX1.DesignCurrently, we tried to investigate the roles of the two loci among 302 NSCL/P trios (129 non-syndromic cleft lip only (NSCLO) trios and 173 non-syndromic cleft lip and cleft palate (NSCLP) trios) from Western Han Chinese. The two SNPs were genotyped by SNPscan method; Hardy–Weinberg equilibrium test, allelic TDT and parent-of-origin effect were performed by PLINK software, and genotypic TDT and haplotype by FBAT software.ResultsAllelic TDT analysis revealed allele A at rs7078160 was over-transmitted among NSCL/P group (P = 0.0086, OR_transmission = 1.36, 95%CI: 1.08–1.72). Parent-of-origin effect analysis revealed a paternal special over-transmission of allele A at rs708260 in NSCL/P group (P = 0.0079). Haplotype AC of rs7078160-rs4752028 was significant over-transmitted in the NSCL/P group.ConclusionsOur study firstly confirmed that allele A at rs7078160 at VAX1 gene was a risk factor for NSCL/P in Western Han Chinese population.     

Further evidence for the involvement of MYH9 in the etiology of non-syndromic cleft lip with or without cleft palate

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common birth defects and has a multifactorial etiology that includes both genetic and environmental components. MYH9 , the gene coding for the heavy chain of non-muscle myosin II, has been considered as a good candidate gene in NSCL/P on the basis of its expression profile during craniofacial morphogenesis. Reports in an Italian sample, as well as in an ethnically mixed North American sample, of a positive association between single-nucleotide polymorphisms in the MYH9 gene and NSCL/P have provided further support for the role of MYH9 in the development of NSCL/P. In the present study, we aimed to replicate these findings by conducting a family-based association study with seven single nucleotide polymorphisms in MYH9 using a sample of 248 NSCL/P patients and their parents. Single marker analysis resulted in a highly significant association for rs7078. In haplotype analysis, the most significant result was obtained for the SNP combination (rs7078; rs2071731; rs739097; rs5995288). Our results thus confirm the potential involvement of MYH9 in the etiology of NSCL/P in our patients of Central European origin, although further studies are warranted to determine its exact pathogenetic role.     

Non-syndromic cleft lip with or without cleft palate in Asian populations: Association analysis on three gene polymorphisms of the folate pathway

ObjectiveOrofacial clefts (OFCs) are one of the most common birth defects in humans. They are the subject of a number of investigations aimed at elucidating the bases of their complex mode of inheritance involving both genetic and environmental factors. Genes belonging to the folate pathway have been among the most studied. The aim of the investigation was to replicate previous studies reporting evidence of association between polymorphisms of folate related genes and the occurrence of non-syndromic cleft lip with or without cleft palate (NSCL/P), using three independent samples of different ancestry: from Tibet, Bangladesh and Iran, respectively.DesignSpecifically, the polymorphisms rs1801133 of MTHFR, rs1801198 of TCN2, and rs4920037 of CBS, were tested.ResultsA decreased risk of NSCL/P was observed in patients presenting the C677T variant at MTHFR gene (relative risk for heterozygotes = 0.53; 95% confidence interval [C.I.] = 0.32–0.87). The investigated polymorphisms mapping at TCN2 and CBS genes did not provide any evidence of association.ConclusionOverall, these results indicate that NSCL/P risk factors differ among populations and confirm the importance of testing putative susceptibility variants in different genetic backgrounds.     

DHFR基因rs11742688位点单核苷酸多态性与中国东北人群唇腭裂相关性研究

目的：探讨二氢叶酸还原酶（DHFR）基因 rs11742688位点单核苷酸多态性与中国东北部人群的非综合征唇腭裂（NSCL／P）的相关性。方法：采用聚合酶链－限制性片段长度多态性方法检测东北地区220例 NSCL／P 及其父母（其中包括138例完整的核心家系）,180例正常儿童作为对照组,进行 HW 平衡检验,用 SPSS 统计学软件对病例组和对照组进行检验及计算 OR 值和95％可信区间。结果：病例对照研究结果显示,东北地区单纯唇裂和唇腭裂 rs11742688位点的 TT 基因型频率差异无显著性（χ2＝0．439,P ＞0．05）。结论：DHFR rs11742688位点 T 等位基因与东北人群的 NSCL／P 无相关性。     

Association between BMP4 gene polymorphisms and cleft lip with or without cleft palate in a population from South China

ObjectivePrevious studies have suggested an association between several polymorphisms of the BMP4 gene and susceptibility to non-syndromic cleft lip with or without cleft palate (NSCL/P) in various populations. However, this association may vary according to ethnic group and the form of NSCL/P. This study analyzed the association between the BMP4 gene polymorphisms rs762642, rs17563, and rs10130587 with the risk of cleft lip only (CLO), cleft palate only (CPO), and cleft lip with palate (CLP) in a population from South China.MethodsThis case-control study included 165 patients with NSCL/P (53 patients with CPO, 52 with CLO, and 60 with CLP) and 52 healthy volunteers. Peripheral blood samples were collected from all subjects to genotype the rs762642, rs17563, and rs10130587 polymorphisms by direct sequencing. Genotype and allelic frequencies of these polymorphisms were compared between healthy volunteers and patients with various forms of NSCL/P.ResultsThe genotype and allelic frequencies of rs762642 differed significantly between subgroups (CPO and CLP) and normal controls, whereas a significant difference was observed only in the CLO subgroup for the rs17563 polymorphism and in the CLO and CLP groups for the rs10130587 polymorphism. In addition, we identified a novel association of a BMP4 gene polymorphism, which was in linkage disequilibrium with the rs10130587 polymorphism, with CLO and CLP.ConclusionThe BMP4 gene polymorphisms rs762642, rs17563, and rs10130587 exhibit different associations with different forms of NSCL/P, suggesting that different forms of NSCL/P may have different etiologies.     

TCN2基因与非综合征性唇腭裂的关系

目的研究叶酸代谢相关基因TCN2与中国人群中非综合征性唇腭裂的关系。方法通过聚合酶链反应-限制性片段长度多态性,在108例非综合征性唇腭裂患者和184名正常对照个体中,对TCN2基因2个单核苷酸多态性（SNP）（rs10418和rs1801198）进行检测。利用拟合优度卡方检验,分析基因型分布频率是否符合Hardy-Weinberg平衡定律;应用UNPHASED软件包分析单个单核苷酸多态性位点以及两个位点单倍型与非综合征性唇腭裂的相关性。结果 2个SNP位点基因型频率分布均符合Hardy-Weinberg平衡;等位基因分布和单倍型组合在非综合征性唇腭裂患者与对照组之间无显著性差异;rs10418 TT基因型能增加非综合征性唇腭裂患病风险。结论 TCN2基因rs10418 TT基因型是非综合征性唇腭裂的危险因素。     

MSX1基因A274V多态性与非综合征性唇腭裂的关系

目的 研究同源异型盒基因1 (muscle segment homeobox1,MSX1) A274V多态性与非综合征性唇腭裂(non-syndromic cleft lip with or without cleft palate,NSCL/P)的关系.方法 利用聚合酶链反应-限制性片段长度多态性方法,在162例非...     

IRF6 gene variants in Central European patients with non‐syndromic cleft lip with or without cleft palate

Variants in the interferon regulatory factor 6 (IRF6) gene have repeatedly been associated with non‐syndromic cleft lip with or without cleft palate (NSCL/P). A recent study has suggested that the functionally relevant variant rs642961 is the underlying cause of the observed associations. We genotyped rs642961 in our Central European case–control sample of 460 NSCL/P patients and 952 controls. In order to investigate whether other IRF6 variants contribute independently to the etiology of NSCL/P, we also genotyped the non‐synonymous coding variant V274I (rs2235371) and five IRF6‐haplotype tagging single nucleotide polymorphisms (SNPs). A highly significant result was observed for rs642961 (P = 1.44 × 10^?6) in our sample. The odds ratio was 1.75 [95% confidence interval (CI): 1.38–2.22] for the heterozygous genotype and 1.94 (95% CI: 1.21–3.10) for the homozygous genotype, values that are similar to those reported in a previously published family‐based study. Our results thus confirm the involvement of the IRF6 variant, rs642961, in the etiology of NSCL/P in the Central European population. We also found evidence suggestive of an independent protective effect of the coding variant V274I. In order to understand fully the genetic architecture of the IRF6 locus, it will be necessary to conduct additional SNP‐based and resequencing studies using large samples of patients.     

Identification of susceptibility genes in non-syndromic cleft lip with or without cleft palate using whole-exome sequencing

Background

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is among the most common congenital malformations. The etiology of NSCL/P remains poorly characterized owing to its complex genetic heterogeneity. The objective of this study was to identify genetic variants that increase susceptibility to NSCL/P.

Material and Methods

Whole-exome sequencing (WES) was performed in 8 fetuses with NSCL/P in China. Bioinformatics analysis was performed using commercially available software. Variants detected by WES were validated by Sanger sequencing.

Results

By filtering out synonymous variants in exons, we identified average 8575 nonsynonymous single nucleotide variants (SNVs). We subsequently compared the SNVs against public databases including NCBI dbSNP build 135 and 1000 Genomes Project and obtained an average of 203 SNVs. Total 12 reported candidate genes were verified by Sanger sequencing. Sanger sequencing also confirmed 16 novel SNVs shared by two or more samples.

Conclusions

We have found and confirmed 16 susceptibility genes responsible for NSCL/P, which may play important role in the etiology of NSCL/P. The susceptibility genes identified in this study will not only be useful in revealing the etiology of NSCL/P but also in diagnosis and treatment of the patients with NSCL/P. Key words:Non-syndromic cleft lip with or without cleft palate, whole-exome sequencing, sanger sequencing, susceptibility gene, single nucleotide variants (SNVs).     

Evaluating SKI as a candidate gene for non‐syndromic cleft lip with or without cleft palate

Non‐syndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common of all congenital malformations and has a multifactorial etiology. Findings in mice suggest that the v‐ski sarcoma viral oncogene homolog (SKI) gene is a candidate gene for orofacial clefting. In humans, a significant association between rs2843159 within SKI and NSCL/P has been reported in patients from the Philippines and South America. In the South American patients, the association was driven by the subgroup of patients with non‐syndromic cleft lip only (NSCLO). Here we investigated the association with rs2843159 in a Mayan Mesoamerican population (172 NSCL/P patients and 366 controls). In addition, we analyzed the phenotypic subgroups NSCLO and non‐syndromic cleft of lip and palate (NSCLP). A trend towards association between rs2843159 and NSCL/P was observed in the Mayan cohort (P = 0.097), and we found a stronger association in the NSCLP subgroup (P = 0.072) despite a limited sample size. To investigate whether other common variants within the SKI gene contribute to NSCL/P susceptibility in European and Asian populations, we also analyzed genotypic data from two recent genome‐wide association studies using set‐based statistical approaches. These analyses detected a trend toward association in the European population. Our data provide limited support for the hypothesis that common SKI variants are susceptibility factors for NSCL/P.     

宁夏回汉族人群Wnt3基因单核苷酸多态性与非综合征型唇腭裂相关性的研究

目的 探讨宁夏回汉族人群中Wnt3基因rs142167和rs7216231位点单核苷酸多态性（SNP）与非综合征型唇腭裂（NSCL/P）的相关性。方法 收集宁夏地区回汉族人群非综合征型唇腭裂患者371例为病例组,其中汉族患者166例,回族患者205例;收集患者父亲196例,患者母亲224例,其中150例患者为NSCL/P核心家系;258例健康新生儿为对照组,其中汉族190例,回族68例。采用聚合酶链反应-限制性片段长度多态性（PCR-RFLP）方法检测Wnt3基因多态位点rs142167和rs7216231基因型,对比分析2组的基因型和等位基因,并进行传递不平衡检验（TDT）和以家系为基础的相关性检验（FBAT）分析。结果 回汉族人群病例组与对照组比较及其民族分层比较,唇裂、腭裂、唇腭裂及总病例组rs142167和rs7216231位点均无统计学差异（P＞0.05）。TDT分析结果显示：rs142167和rs7216231位点的等位基因均不存在过传递（P＞0.05）。FBAT分析结果显示：单倍型G-G具有统计学意义（P<0.05）。结论 Wnt3基因多态性与宁夏地区回汉族人群非综合征型唇腭裂不存在相关性。     

亚甲基四氢叶酸还原酶C677T多态性与非综合征性唇腭裂的关系

目的研究亚甲基四氢叶酸还原酶基因C677T多态性与非综合征性唇腭裂的关系。方法利用聚合酶链反应-限制性片段长度多态性方法（PCR-RFLP）,在168例非综合征性唇腭裂患者和192名正常对照中,对MTHFR基因C677T单核苷酸多态性（SNP,rs1801133）进行检测。利用拟合优度卡方检验,分析基因型分布频率是否符合Hardy-Weinberg平衡定律;应用UNPHASED软件包分析多态性位点与非综合征性唇腭裂的相关性。结果MTHFRC677T多态性基因型频率分布符合Hardy-Weinberg平衡;MTHFR C677T等位基因分布在NSCL／P组与对照组之间有显著性差异（P〈0.05）,正常组中T等位基因的频率明显高于NSCL／P组。结论MTHFR C677T多态性位点在中国人群中与非综合征性唇腭裂形成的发生相关联。     

Familial non-syndromic cleft lip and palate--analysis of the IRF6 gene and clinical phenotypes

The aim of this study was to characterize Swedish families with non-syndromic cleft lip and/or palate (NSCL/P) for mutations or other sequence variants in the interferon regulatory factor 6 (IRF6) gene, as well as to describe their cleft phenotypes and hypodontia. Seventeen Swedish families with at least two family members with NSCL/P were identified and clinically evaluated. Extracted DNA from blood samples was used for IRF6 mutation screening. Exonic fragments of the IRF6 gene were sequenced and chromatograms were inspected. Statistical analysis was undertaken with marker- and haplotype association tests. No disease-associated IRF6 mutation could be determined in the families analyzed. One new and seven known single nucleotide polymorphisms (SNPs) were detected. The A allele of SNP rs861019 in exon 2 and the G allele of SNP rs7552506 in intron 3 showed association with cleft lip and palate (CLP; odds ratios of 3.1 and 5.45, respectively). Hypodontia was observed more commonly in individuals affected with CL/P as compared with family members without a cleft (P < 0.01). The hypodontia most often affected the cleft area, possibly representing a secondary effect. The distribution of cleft phenotypes in 15 of the 17 families with NSCL/P differed from the mixed cleft types seen in Van der Woude syndrome (VWS), in that CLP did not occur together with an isolated cleft palate within the same family. It was concluded that mutations of the IRF6 gene are not a common cause for cleft predisposition in Swedish NSCL/P families.     

Gene-gene interaction for nonsyndromic cleft lip with or without cleft palate in Chilean case-parent trios

ObjectiveNonsyndromic cleft lip with or without cleft palate (NSCL/P) is a birth defect for which several genes susceptibility genes been proposed. Consequently, it has been suggested that many of these genes belong to common inter-related pathways during craniofacial development gene-gene interaction. We evaluated the presence of gene-gene interaction for single nucleotide polymorphisms within interferon regulatory factor 6 (IRF6), muscle segment homeobox 1 (MSX1), bone morphogenetic protein 4 (BMP4) and transforming growth factor 3 (TGFB3) genes in NSCL/P risk in Chilean case-parent trios.DesignFrom previous studies, we retrieved genotypes for 13 polymorphic variants within these four genes in 152 case-parent trios. Using the trio package (R) we evaluate the gene-gen interaction in genetic markers pairs applying a 1°-of-freedom test (1df) and a confirmatory 4°-of-freedom (4df) test for epistasis followed by both a permutation test and a Benjamini-Hochberg test for multiple comparisons adjustment.ResultsWe found evidence of gene-gene interaction for rs6446693 (MSX1) and rs2268625 (TGFB3) (4df p = 0.024; permutation p = 0.015, Benjamini-Hochberg p = 0.001).ConclusionsA significant gene-gene interaction was detected for rs6446693 (MSX1) and rs2268625 (TGFB3). This finding is concordant with research in animal models showing that MSX1 and TGFB3 are expressed in common molecular pathways acting in an epistatic manner during maxillofacial development.     

宁夏地区非综合征型唇腭裂环境因素的研究

目的 探讨宁夏地区非综合征型唇腭裂（NSCL/P）发病相关环境因素。方法 采用病例对照研究方法纳入NSCL/P患者453例,正常新生儿452例。对研究对象进行问卷调查,利用SPSS 16.0统计软件对数据进行卡方检验和Logistic回归分析。结果 NSCL/P患病类型构成比为唇裂︰唇裂合并腭裂︰腭裂=1︰2.02︰1.51。Logistic回归分析显示妊娠期发生异常、妊娠期感染、流产史、孕前孕中服用药物、饮茶、吸烟、饮酒、居住地附近工厂为危险因素（P<0.05）。单胎、早孕反应、食用豆制品食物、水果为保护因素（P<0.05）。结论 加强母亲孕期饮食均衡,避免感染、流产、服用药物以及不良生活习惯对降低NSCL/P的发生具有重要意义。     

Association of muscle segment homeobox gene 1 polymorphisms with nonsyndromic cleft lip with or without cleft palate

OBJECTIVE: Muscle segment homeobox gene (MSX)1 has been proposed as a gene in which mutations may contribute to nonsyndromic cleft lip with or without cleft palate (NSCL/P). To study MSX1 polymorphisms in NSCL/ P by means of polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP), and investigate the association of MSX1 exons 1 polymorphisms with NSCL/P. METHODS: DNA were extracted from blood samples from NSCL/P and unrelated normal subjects. Genome DNA from peripheral leukocyte with these blood samples were extracted, which was used as template to amplify desired gene fragment of MSX1 exons 1 by means of polymerase chain reaction (PCR). The PCR products were examined by single-strand conformation polymorphism (SSCP). The MSX1 exons 1 polymorphisms were examined by sequencing if mutations were found. RESULTS: MSX1 genes of exon 1 mutation was not been found in the NSCL/P and unrelated normal subjects by SSCP. CONCLUSION: No correlation between MSX1 exon 1 and NSCL/P was found. MSX1 exon 1 may not be a key gene (susceptibility gene) in NSCL/P.     

非综合征性唇腭裂与同源异型盒基因1多态性的相关性研究

目的采用聚合酶链反应- 单链构象多态性（PCR- SSCP）方法研究同源异型盒基因（MSX）1外显子1的编码区，探讨非综合征性唇腭裂（NSCL/P）患者MSX1基因外显子1的编码区内是否存在基因突变。方法采用聚合酶链反应（PCR）和单链构象多态性（SSCP）方法，以45名健康人为对照组，45名NSCL/P患者作为研究对象，分析MSX1基因多态性。结果SSCP分析显示NSCL/P患者（45名）与对照组（45名）样本的电泳速率相同，提示无多态性存在。结论MSX1基因外显子1未发现多态性的存在，其与NSCL/P患者之间无明显相关性。     

Homozygote C/C at rs12543318 was risk factor for non‐syndromic cleft lip only from Western Han Chinese population

Non‐syndromic cleft lip with or without cleft palate (NSCL/P) is a complex disorder, and it results from both of the genetic modifiers and environmental factors, with genetic modifiers contributes to it more than environmental factors. GWASs made great progress in identifying the candidate genes for NSCL/P, but the findings need to be replicated in other populations. In this study, we selected eleven SNPs from recent GWASs and GWAS meta‐analysis to investigate their associations among 308 NSCL/P trios (134 non‐syndromic cleft lip only (NSCLO) trios and 174 non‐syndromic cleft lip with cleft palate (NSCLP) trios) from Han Chinese population. All SNPs were genotyped using SNPscan method and analyzed the data with FBAT, PLINK, and R package. Allelic TDT analysis showed that allele A at rs12543318 was associated with NSCLO trios (P = .0032, OR = 0.57, 95% CI: 0.39‐0.83), and parent‐of‐origin effect analysis indicated that allele A at rs12543318 was significantly maternally undertransmitted among NSCLO (P = .0046), which implied the potential influence of genomic imprinting; global TDT further confirmed this association. Individual genotypic TDT showed homozygote C/C at rs12543318 was overtransmitted among NSCLO (Z = 3.79, P = .00015) and NSCL/P groups (Z = 3.83, P = .00013), which indicated that it could increase the risk to have cleft babies. Our findings indicated that rs12543318 was associated with NSCLO from Western Han Chinese population, which will give new scientific evidence for later researches in the etiology of NSOCs.