IRF6 rs2235375 single nucleotide polymorphism is associated with isolated non-syndromic cleft palate but not with cleft lip with or without palate in South Indian population

Simultaneous Occurrence of Hypospadias and Bilateral Cleft Lip and Jaw in a Crossbred Calf: Clinical, Computer Tomographic, and Genomic Characterization

Congenital abnormalities in animals, including abnormalities of the cleft lip and jaw and hypospadias have been reported in all domesticated species. They are a major concern for breeders due to the increased economic loss they entail. In this article, we described a congenital bilateral cheilognathoschisis (cleft lip and jaw) with campylognathia in association with penile hypospadias and preputial hypoplasia with failure of preputial fusion in a Bos taurus crossbred Piedmontese × Wagyu calf. Clinical examination, computed tomography, and whole genome sequencing were performed to describe and identify a possible cause of the abnormalities. Clinical examination revealed a bilateral cheilognathoschisis of approximately 4 cm in length and 3 cm in width in the widest part, with computer tomography analyses confirming the bilateral absence of the processus nasalis of the incisive bone and the lateral deviation of the processus palatinus towards the left side. Genomic data analyses identified 13 mutations with a high impact on the products of the following overlapped genes: ACVR1, ADGRA2, BHMT2, BMPR1B, CCDC8, CDH1, EGF, F13A1, GSTP1, IRF6, MMP14, MYBPHL, and PHC2 with ADGRA2, EGF, F13A1, GSTP1, and IRF6 having mutations in a homozygous state. The whole genome investigation indicates the involvement of multiple genes in the birth defects observed in this case.

Association of single nucleotide polymorphisms in the IRF6 gene with nonsyndromic cleft lip with or without cleft palate in Kinh Vietnamese patients

BACKGROUND

The interferon regulatory factor 6 (IRF6) gene, which causes Van der Woude syndrome, is associated with nonsyndromic cleft lip with or without cleft palate (NSCL/P). Single nucleotide polymorphisms (SNPs) in the IRF6 gene were identified as susceptibility indicators of this defect in several populations. To further evaluate its role in this birth defect, we conducted this study with the aim of identifying allele frequencies, genotype frequencies, and associations of 5 SNPs (rs2235373, rs2235371, rs2235375, rs2013162, and rs2236907) in the IRF6 gene with NSCL/P in Kinh Vietnamese patients.

METHODS

A total of 132 patients with NSCL/P and 132 healthy individuals were included in our study group. Direct sequencing was performed to genotype the tag SNPs. Genetic models were used to compare genotype and allele frequencies between the case and control groups.

RESULTS

In the recessive model, the genotypes C/C of rs2236907, C/C of rs2013162, G/G of rs2235375, and A/A of rs2235373 were associated with an increased risk of NSCL/P, whereas there was no clear association between rs2235371 and the malformation in any genetic model. When subgroup analysis was performed, we observed a similar risk trend in the cleft lip and palate, cleft palate only and cleft lip only phenotypes. In haplotype analysis, haplotype models of 5 tag SNPs were associated with increased risks of this defect in all phenotypic models (OR_GCGCC/CCAA = 23.64, 95% CI 12.28-45.49, p < 0.0001).

CONCLUSIONS

These findings point to a considerable contribution of rs2236907, rs2013162, rs2235373, and rs2235375 to the NSCL/P defect in Kinh Vietnamese individuals.

Association of Axis Inhibition Protein 2 Polymorphisms with Non-Syndromic Cleft Lip with or without Cleft Palate in Iranian Children

Background: Previously, only a few studies have investigated the association of AXIN2 polymorphisms with nonsyndromic cleft lip with or without cleft palate (NSCLP) risk. Objective: The aim of this study was to examine the association of rs2240308 C > T, rs1133683 C > T, and rs7224837 A > G polymorphisms of the AXIN2 gene with NSCLP risk in Iranian children. Methods: The study was comprised of 120 NSCLP cases and 120 controls. The AXIN2 polymorphisms were genotyped using PCR-RFLP assay. Results: The mutant homozygote genotype (TT) of AXIN2 rs1133683 C > T polymorphism was associated with increased risk of NSCLP. There was no significant association between rs2240308 C > T and rs7224837 A > G polymorphisms of the AXIN2 gene with an increased risk of NSCLP. Conclusion: This study indicates that AXIN2 rs1133683 C > T polymorphism may modify NSCLP susceptibility in the Iranian children, but not the rs2240308 C > T and rs7224837 A > G polymorphisms.

Genetic factors define CPO and CLO subtypes of nonsyndromicorofacial cleft

Nonsyndromic orofacial cleft (NSOFC) is a severe birth defect that occurs early in embryonic development and includes the subtypes cleft palate only (CPO), cleft lip only (CLO) and cleft lip with cleft palate (CLP). Given a lack of specific genetic factor analysis for CPO and CLO, the present study aimed to dissect the landscape of genetic factors underlying the pathogenesis of these two subtypes using 6,986 cases and 10,165 controls. By combining a genome-wide association study (GWAS) for specific subtypes of CPO and CLO, as well as functional gene network and ontology pathway analysis, we identified 18 genes/loci that surpassed genome-wide significance (P < 5 × 10⁻⁸) responsible for NSOFC, including nine for CPO, seven for CLO, two for both conditions and four that contribute to the CLP subtype. Among these 18 genes/loci, 14 are novel and identified in this study and 12 contain developmental transcription factors (TFs), suggesting that TFs are the key factors for the pathogenesis of NSOFC subtypes. Interestingly, we observed an opposite effect of the genetic variants in the IRF6 gene for CPO and CLO. Moreover, the gene expression dosage effect of IRF6 with two different alleles at the same single-nucleotide polymorphism (SNP) plays important roles in driving CPO or CLO. In addition, PAX9 is a key TF for CPO. Our findings define subtypes of NSOFC using genetic factors and their functional ontologies and provide a clue to improve their diagnosis and treatment in the future.

Although GWAS have discovered 43 genes/loci associated with NSOFC, most previous studies used mixed samples of CL/P subtypes rather than CPO or CLO separately. Our findings define the CPO and CLO subtypes using genetic factors and their functional ontologies based on CPO and CLO GWAS data. In this study, we identified 18 genes/loci that contribute to CPO, CLO or CLP. Fourteen of them are novel and identified, and 12 contain developmental transcription factors (TFs), suggesting that TFs are the key factors for the pathogenesis of NSOFC subtypes. We observed an opposite effect in the strongest associated locus IRF6 for CPO and CLO; this information was omitted by previous CL/P GWAS. Furthermore, we reveal that the gene expression dosage of IRF6 plays important roles in driving CPO or CLO. In addition, we found that PAX9 is a strong genetic factor for CPO. These results suggest that transcription factors are the key genetic reason for the pathogenesis of NSOFC subtypes.

IRF6 polymorphisms in Brazilian patients with non-syndromic cleft lip with or without palate

INTRODUCTION

Non-syndromic orofacial clefts have a complex etiology due to the contribution from both genetic and environmental risk factors, as well as the interaction between them. Among the more than 15 susceptibility loci for non-syndromic orofacial clefts with considerable statistical and biological support, the IRF6 is the most validated gene by the majority of studies. Nonetheless, in genetically heterogeneous populations such as Brazilian, the confirmation of association between non-syndromic orofacial clefts and IRF6 common variants is not a consolidated fact and unrecognized IRF6 variants are poorly investigated.

OBJECTIVE

The aim of this study was to investigate the association of IRF6 polymorphisms with non-syndromic orofacial clefts development in a population from northeast Brazil.

METHODS

Blood samples of 186 non-syndromic orofacial clefts patients and 182 controls from Rio Grande do Norte, Brazil, were obtained to analyze IRF6 polymorphisms (rs2235371, rs642961, rs2236907, rs861019, and rs1044516) by real-time polymerase chain reaction. Non-syndromic orofacial clefts patients were classified in cleft lip and palate, cleft palate only and cleft lip only groups.

RESULTS

The genotype and allele frequencies of single nucleotide polymorphism rs2235371 in IRF6 showed significant differences in patients with cleft palate when compared to the controls, whereas no association was shown between rs642961, rs2236907, rs861019, and rs1044516 and non-syndromic orofacial clefts.

CONCLUSION

The association found between rs2235371 and isolated cleft palate should be interpreted with caution due to the low number of individuals investigated, and more studies with larger sample size are needed to confirm these association. In addition, there is a lack of association of the rs642961, rs2236907 and rs861019 polymorphisms with non-syndromic orofacial clefts susceptibility.

The Densitometric Analysis of Protein Pattern in Cleft Lip and Palate Patients

Objectives

Cleft lip and palate (CLP) belongs to the congenital anomaly that is clinically seen as cleft in lip, alveolar bone, palate, and nasal septum. The patients suffer from esthetic and various functional defects. CLP is resulted from impaired palatogenesis during the embryonic phase. The etiology of CLP is influenced by genetic, environmental, and combination of both. According to the literature, CLP is highly associated with defect in interferon regulatory factor 6 (IRF6) and poliovirus receptor-like (PVRL1) genes. The present study aimed to investigate the total protein profile and to identify protein IRF6 and PVRL1 in plasma of CLP patients.

Materials and Methods

Dot-Blot analysis was performed to identify protein target of IRF6 and PVRL1. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed in gel concentration 12% using plasma of CLP patients, their parents, and control population. The gels were stained by Coomassie blue afterward. Gels were analyzed through ImageLab 5.2.1 software.

Results

The intensity of major bands in CLP patients was darker than control group, but remains similar to the parents group. The target protein IRF6 and PVRL1 were positively identified through Dot-Blot. Retardation factor value was significantly different in major bands of CLP patients compared to control group.

Conclusion

There pattern of protein profile in CLP patients was different compared to non-CLP.