Association of MMP3 and TIMP2 promoter polymorphisms with nonsyndromic oral clefts

Exploring the role of the WNT5A rs566926 polymorphism and its interactions in non-syndromic orofacial cleft: a multicenter study in Brazil

BACKGROUND

Associations between the WNT5A rs566926 variant and non-syndromic orofacial cleft (NSOC) have been reported in different populations.

OBJECTIVE

This study aimed to investigate the role of the rs566926 single nucleotide polymorphism (SNP) in WNT5A and its interactions with SNPs in BMP4, FGFR1, GREM1, MMP2, and WNT3 in the occurrence of NSOC in a Brazilian population.

METHODOLOGY

A case-control genetic association study was carried out involving participants from four regions of Brazil, totaling 801 patients with non-syndromic cleft lip with or without cleft palate (NSCL±P), 273 patients with cleft palate only (NSCPO), and 881 health volunteers without any congenital condition (control). Applying TaqMan allelic discrimination assays, we evaluated WNT5A rs566926 in an ancestry-structured multiple logistic regression analysis, considering sex and genomic ancestry as covariates. Interactions between rs566926 and variants in genes involved in the WNT5A signaling pathway (BMP4, FGFR1, GREM1, MMP2, and WNT3) were also explored.

RESULTS

WNT5A rs566926 was significantly associated with an increased risk of NSCL±P, particularly due to a strong association with non-syndromic cleft lip only (NSCLO), in which the C allele increased the risk by 32% (OR: 1.32, 95% CI: 1.04-1.67, p=0.01). According to the proportions of European and African genomic ancestry, the association of rs566926 reached significant levels only in patients with European ancestry. Multiple interactions were detected between WNT5A rs566926 and BMP4 rs2071047, GREM1 rs16969681 and rs16969862, and FGFR1 rs7829058.

CONCLUSION

The WNT5A rs566926 polymorphism was associated with NSCL±P, particularly in individuals with NSCLO and high European ancestry. Epistatic interactions involving WNT5A rs566926 and variants in BMP4, GREM1, and FGFR1 may contribute to the risk of NSCL±P in the Brazilian population.

Evaluation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in human cases with orofacial clefts: A systematic review

INTRODUCTION

The interaction between several cell populations or many genes and the coordination of multiple signal transmission pathways can lead to defects such as orofacial clefts (OFCs). Herein, a systematic review was designed to evaluate a group of important biomarkers (matrix metalloproteinases [MMPs] and tissue inhibitors of metalloproteinases [TIMPs]) in human cases with OFCs.

MATERIAL AND METHODS

Four databases including PubMed, Scopus, Web of Science, and Cochrane Library databases were searched until March 10, 2023, without any restriction. STRING, the protein-protein interaction (PPI) network software, was applied to investigate the functional interactions among the examined genes. The effect sizes including odds ratio (OR) dealing with a 95% confidence interval (CI), were extracted by the Comprehensive Meta-Analysis version 2.0 (CMA 2.0) software.

RESULTS

Thirty-one articles were entered into the systematic review that four articles were analyzed in the meta-analysis. Single studies reported that several polymorphisms of MMPs (rs243865, rs9923304, rs17576, rs6094237, rs7119194, and rs7188573); and TIMPs (rs8179096, rs7502916, rs4789936, rs6501266, rs7211674, rs7212662, and rs242082) had an association with OFC risk. There was no significant difference for MMP-3 rs3025058 polymorphism in allelic (OR: 0.832; P=0.490), dominant (OR: 1.177; P=0.873), and recessive (OR: 0.363; P=0.433) models and MMP-9 rs17576 polymorphism in an allelic model (OR: 0.885; P=0.107) between the OFC cases and the controls. Based on immunohistochemistry reports, three MMPs (MMP-2, MMP-8, and MMP-9) and TIMP-2 had significant correlations with several other biomarkers in OFC cases.

CONCLUSIONS

MMPs and TIMPs can impact the tissue and cells affected by OFCs and the process of apoptosis. The interaction between some biomarkers with MMPs and TIMPs (e.g., TGFb1) in OFCs can be interesting for future research.

Brazilian Multiethnic Association Study of Genetic Variant Interactions among FOS, CASP8, MMP2 and CRISPLD2 in the Risk of Nonsyndromic Cleft Lip with or without Cleft Palate

Associations of CRISPLD2 (cysteine-rich secretory protein LCCL domain containing 2) and genes belonging to its activation pathway, including FOS (Fos proto-oncogene), CASP8 (caspase 8) and MMP2 (matrix metalloproteinase 2), with nonsyndromic orofacial cleft risk, have been reported, but the results are yet unclear. The aim of this study was to evaluate single nucleotide polymorphisms (SNPs) in FOS, CASP8 and MMP2 and to determine their SNP-SNP interactions with CRISPLD2 variants in the risk of nonsyndromic cleft lip with or without cleft palate (NSCL±P) in the Brazilian population. The SNPs rs1046117 (FOS), rs3769825 (CASP8) and rs243836 (MMP2) were genotyped using TaqMan allelic discrimination assays in a case-control sample containing 801 NSCL±P patients (233 nonsyndromic cleft lip only (NSCLO) and 568 nonsyndromic cleft lip and palate (NSCLP)) and 881 healthy controls via logistic regression analysis adjusted for the effects of sex and genomic ancestry proportions with a multiple comparison p value set at ≤0.01. SNP-SNP interactions with rs1546124, rs8061351, rs2326398 and rs4783099 in CRISPLD2 were performed with the model-based multifactor dimensionality reduction test complemented with a 1000 permutation-based strategy. Although the association between FOS rs1046117 and risk of NSCL±P reached only nominal p values, NSCLO risk was significantly higher in carriers of the FOS rs1046117 C allele (OR: 1.28, 95% CI: 1.10-1.64, p = 0.004), TC heterozygous genotype (OR: 1.59, 95% CI: 1.16-2.18, p = 0.003), and in the dominant model (OR: 1.50, 95% CI: 1.10-2.02, p = 0.007). Individually, no significant associations between cleft risk and the SNPs in CASP8 and MMP2 were observed. SNP-SNP interactions involving CRISPLD2 variants and rs1046117 (FOS), rs3769825 (CASP8) and rs243836 (MMP2) yielded several significant p values, mostly driven by FOS rs1046117 and CASP8 rs3769825 in NSCL±P, FOS rs1046117 in NSCLO and CRISPLD2 rs8061351 in NSCLP. Our study is the first in the Brazilian population to reveal the association of FOS rs1046117 with NSCLO risk, and to support that CRISPLD2, CASP8, FOS and MMP2 interactions may be related to the pathogenesis of this common craniofacial malformation.

Evaluation of the Multiple Tissue Factors in the Cartilage of Primary and Secondary Rhinoplasty in Cleft Lip and Palate Patients

Cleft lip and palate (CLP) is one of the craniofacial defects. The objective of this study was to identify the differences in appearance between the tissue factors in cartilage of CLP patients after primary and secondary rhinoplasty. Immunohistochemistry was performed with MMP-2, MMP-8, MMP-9, TIMP-2, IL-1α, IL-10, bFGF, and TGFβ1. The quantification of the structures was performed using a semi-quantitative census method. MMP-2, -9, IL-1a, and bFGF demonstrated higher number of positive cells in patients, while the number of MMP-8, IL-1a, -10 and TGFβ1 cells was higher or equal in the control subjects. The only statistically significant difference between CLP-operated patients was found in the TIMP-2 group, where the primary CLP patient group had a higher number of TIMP-2 positive chondrocytes than the secondary CLP patient group (U = 53.5; p = 0.021). The median value of the primary CLP group was ++ number of TIMP-2 positive chondrocytes compared to +++ in the secondary CLP group. No statistically significant difference was found between primary and secondary rhinoplasty patients for other tissue factors. Commonly, the rich expression of different tissue factors suggests a stimulation of higher elasticity in cleft affected cartilage. The statistically significant TIMP-2 elevation in primary operated cartilage indicates an impact of the selective tissue remodeling for hard tissue.

Polygenic risk impacts PDGFRA mutation penetrance in non-syndromic cleft lip and palate

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common, severe craniofacial malformation that imposes significant medical, psychosocial and financial burdens. NSCL/P is a multifactorial disorder with genetic and environmental factors playing etiologic roles. Currently, only 25% of the genetic variation underlying NSCL/P has been identified by linkage, candidate gene and genome-wide association studies. In this study, whole-genome sequencing and genome-wide genotyping followed by polygenic risk score (PRS) and linkage analyses were used to identify the genetic etiology of NSCL/P in a large three-generation family. We identified a rare missense variant in PDGFRA (c.C2740T; p.R914W) as potentially etiologic in a gene-based association test using pVAAST (P = 1.78 × 10-4) and showed decreased penetrance. PRS analysis suggested that variant penetrance was likely modified by common NSCL/P risk variants, with lower scores found among unaffected carriers. Linkage analysis provided additional support for PRS-modified penetrance, with a 7.4-fold increase in likelihood after conditioning on PRS. Functional characterization experiments showed that the putatively causal variant was null for signaling activity in vitro; further, perturbation of pdgfra in zebrafish embryos resulted in unilateral orofacial clefting. Our findings show that a rare PDGFRA variant, modified by additional common NSCL/P risk variants, have a profound effect on NSCL/P risk. These data provide compelling evidence for multifactorial inheritance long postulated to underlie NSCL/P and may explain some unusual familial patterns.

Genetic markers for non-syndromic orofacial clefts in populations of European ancestry: a meta-analysis

To date, the involvement of various genetic markers in the aetiopathogenesis of non-syndromic orofacial cleft (nsOFC) has been extensively studied. In the present study, we focused on studies performed on populations of European ancestry to systematically review the available literature to define relevant genetic risk factors for nsOFC. Eligible studies were obtained by searching Ovid Medline and Ovid Embase. We gathered the genetic markers from population-based case–control studies on nsOFC, and conducted meta-analysis on the repeatedly reported markers. Whenever possible, we performed stratified analysis based on different nsOFC phenotypes, using allelic, dominant, recessive and overdominant genetic models. Effect sizes were expressed as pooled odds ratios (ORs) with 95% confidence intervals (CIs), and p ≤ 0.05 were considered statistically significant. A total of 84 studies were eligible for this systematic review, with > 700 markers included. Of these, 43 studies were included in the meta-analysis. We analysed 47 genetic variants in 30 genes/loci, which resulted in 226 forest plots. There were statistically significant associations between at least one of the nsOFC phenotypes and 19 genetic variants in 13 genes/loci. These data suggest that IRF6, GRHL3, 8q24, VAX1, TGFA, FOXE1, ABCA4, NOG, GREM1, AXIN2, DVL2, WNT3A and WNT5A have high potential as biomarkers of nsOFC in populations of European descent. Although other meta-analyses that included European samples have been performed on a limited number of genetic variants, this study represents the first meta-analysis of all genetic markers that have been studied in connection with nsOFC in populations of European ancestry.

DNA Methylation Variation Is Identified in Monozygotic Twins Discordant for Non-syndromic Cleft Lip and Palate

Non-syndromic cleft lip with or without cleft palate (NSCLP) is the most common craniofacial birth defect. The etiology of NSCLP is complex with multiple genes and environmental factors playing causal roles. Although studies have identified numerous genetic markers associated with NSCLP, the role of epigenetic variation remains relatively unexplored. Because of their identical DNA sequences, monozygotic (MZ) twins discordant for NSCLP are an ideal model for examining the potential contribution of DNA methylation to non-syndromic orofacial clefting. In this study, we compared the patterns of whole genome DNA methylation in six MZ twin pairs discordant for NSCLP. Differentially methylated positions (DMPs) and regions (DMRs) were identified in NSCLP candidate genes, including differential methylation in MAFB and ZEB2 in two independent MZ twin pairs. In addition to DNA methylation differences in NSCLP candidate genes, we found common differential methylation in genes belonging to the Hippo signaling pathway, implicating this mechanosensory pathway in the etiology of NSCLP. The results of this novel approach using MZ twins discordant for NSCLP suggests that differential methylation is one mechanism contributing to NSCLP, meriting future studies on the role of DNA methylation in familial and sporadic NSCLP.

The Association of Matrix Metalloproteinase Gene Polymorphisms and Periodontitis: An Overview

Periodontitis is a multifactorial inflammatory disease, pathogenic bacteria being the primary etiological agents. The host response and the severity of clinical manifestation are determined by genetic and environmental factors. There is some evidence that the individual response to environmental variations in the immune response in periodontitis is associated with genetic factors. Matrix metalloproteinases (MMPs) are a family of proteolytic enzymes located in the extracellular matrix. Their primary function is the breakdown of connective tissue components. Their role in the oral cavity is very vital. In this literature review, we summarized the contemporary knowledge on the function of MMPs in oral cavity and periodontal disease.

Talon Cusp Associates With MMP2 in a Cohort of Individuals Born With Oral Clefts

OBJECTIVE

The aim of this study was to use dental development as a tool to subphenotype oral clefts and investigate the association of MMP2 with dentin-pulp complex anomalies, in order to identify dental anomalies that are a part of a "cleft syndrome."

DESIGN

Two hundred and ninety individuals born with cleft lip and palate were evaluated and several clinical features, such as cleft completeness or incompleteness, laterality, and presence of dental anomalies were used to assess each individual's cleft status. We tested for overrepresentation of MMP2 single nucleotide polymorphism rs9923304 alleles depending on individuals having certain dental anomalies. Chi-square and Fisher exact tests were used in all comparisons (α = .05).

RESULTS

All individuals studied had at least one dental anomaly outside the cleft area. Significant differences between individuals born with clefts with and without talon cusp (P = .04) were observed for the frequency of the MMP2 less common allele.

CONCLUSION

All individuals born with cleft lip and palate had alterations of the dentition, and a quarter to half of the individuals had alterations of the internal anatomy of their teeth, which further indicates that dental anomalies can be considered as an extended phenotype for clefts. MMP2 was associated with talon cusp in individuals born with oral clefts.

Cellular and developmental basis of orofacial clefts

During craniofacial development, defective growth and fusion of the upper lip and/or palate can cause orofacial clefts (OFCs), which are among the most common structural birth defects in humans. The developmental basis of OFCs includes morphogenesis of the upper lip, primary palate, secondary palate, and other orofacial structures, each consisting of diverse cell types originating from all three germ layers: the ectoderm, mesoderm, and endoderm. Cranial neural crest cells and orofacial epithelial cells are two major cell types that interact with various cell lineages and play key roles in orofacial development. The cellular basis of OFCs involves defective execution in any one or several of the following processes: neural crest induction, epithelial-mesenchymal transition, migration, proliferation, differentiation, apoptosis, primary cilia formation and its signaling transduction, epithelial seam formation and disappearance, periderm formation and peeling, convergence and extrusion of palatal epithelial seam cells, cell adhesion, cytoskeleton dynamics, and extracellular matrix function. The latest cellular and developmental findings may provide a basis for better understanding of the underlying genetic, epigenetic, environmental, and molecular mechanisms of OFCs.

Evidence for craniofacial enhancer variation underlying nonsyndromic cleft lip and palate

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common birth defect for which only ~ 20% of the underlying genetic variation has been identified. Variants in noncoding regions have been increasingly suggested to contribute to the missing heritability. In this study, we investigated whether variation in craniofacial enhancers contributes to NSCLP. Candidate enhancers were identified using VISTA Enhancer Browser and previous publications. Prioritization was based on patterning defects in knockout mice, deletion/duplication of craniofacial genes in animal models and results of whole exome/whole genome sequencing studies. This resulted in 20 craniofacial enhancers to be investigated. Custom amplicon-based sequencing probes were designed and used for sequencing 380 NSCLP probands (from multiplex and simplex families of non-Hispanic white (NHW) and Hispanic ethnicities) using Illumina MiSeq. The frequencies of identified variants were compared to ethnically matched European (CEU) and Los Angeles Mexican (MXL) control genomes and used for association analyses. Variants in mm427/MSX1 and hs1582/SPRY1 showed genome-wide significant association with NSCLP (p ≤ 6.4 × 10^-11). In silico analysis showed that these enhancer variants may disrupt important transcription factor binding sites. Haplotypes involving these enhancers and also mm435/ABCA4 were significantly associated with NSCLP, especially in NHW (p ≤ 6.3 × 10^-7). Importantly, groupwise burden analysis showed several enhancer combinations significantly over-represented in NSCLP individuals, revealing novel NSCLP pathways and supporting a polygenic inheritance model. Our findings support the role of craniofacial enhancer sequence variation in the etiology of NSCLP.

Extracellular Matrix Composition and Remodeling: Current Perspectives on Secondary Palate Formation, Cleft Lip/Palate, and Palatal Reconstruction

Craniofacial development comprises a complex process in humans in which failures or disturbances frequently lead to congenital anomalies. Cleft lip with/without palate (CL/P) is a common congenital anomaly that occurs due to variations in craniofacial development genes, and may occur as part of a syndrome, or more commonly in isolated forms (non-syndromic). The etiology of CL/P is multifactorial with genes, environmental factors, and their potential interactions contributing to the condition. Rehabilitation of CL/P patients requires a multidisciplinary team to perform the multiple surgical, dental, and psychological interventions required throughout the patient's life. Despite progress, lip/palatal reconstruction is still a major treatment challenge. Genetic mutations and polymorphisms in several genes, including extracellular matrix (ECM) genes, soluble factors, and enzymes responsible for ECM remodeling (e.g., metalloproteinases), have been suggested to play a role in the etiology of CL/P; hence, these may be considered likely targets for the development of new preventive and/or therapeutic strategies. In this context, investigations are being conducted on new therapeutic approaches based on tissue bioengineering, associating stem cells with biomaterials, signaling molecules, and innovative technologies. In this review, we discuss the role of genes involved in ECM composition and remodeling during secondary palate formation and pathogenesis and genetic etiology of CL/P. We also discuss potential therapeutic approaches using bioactive molecules and principles of tissue bioengineering for state-of-the-art CL/P repair and palatal reconstruction.

TGFβ3, MSX1, and MMP3 as Candidates for NSCL±P in an Indian Population

OBJECTIVE

To evaluate the association of transforming growth factor β3 ( TGFβ3), muscle segment homeobox 1 ( MSX1), Metalloproteinases 3 ( MMP3), and MMP9 genes as candidates for nonsyndromic cleft lip and/or palate in an Indian population.

DESIGN

Case-control association study, mutational screening, and functional evaluation of obtained mutations.

SETTING

Mutational screening of the developmental genes, TGFβ3 and MSX1, along with functional evaluation and association of promoter region SNPs-one each in MMP3 and MMP9.

PATIENTS, PARTICIPANTS

Two hundred forty five NSCL±P cases from G. S. Memorial Plastic Surgery Hospital and Trauma Center, Varanasi and 201 healthy controls without a family history of congenital malformations from nearby schools, primary health centers, and the university hospital.

MAIN OUTCOME MEASURE(S)

Sequencing, SSCP, and PCR-RFLP were used for candidate gene screening. MatInspector and electrophoretic mobility shift assay (EMSA) were used to check the differential transcription factor binding of the variants at promoter region. Luciferase assay was used to test the transcriptional potential of the variant, and evaluation of the alternative splice site was carried out using exon-trapping experiment.

RESULTS

Metalloproteinases3 -1171 5A/6A was associated with NSCL±P, whereas MMP9 -1562 C/T did not show association. A rare variant in the promoter region of TGFβ3 (rs117462711) creates a differential binding site, confirmed by EMSA. Luciferase assay showed 3.7-fold increased expression level in mutant construct. A synonymous change in MSX1 (rs34165410) showed association with NSCL±P, which may create an alternative splice site or lead to low codon usage. Exon-trapping experiment failed to confirm alternative splicing, indicating low codon usage frequency of the mutant affecting the gene function.

CONCLUSIONS

TGFβ3, MSX1, and MMP3 are candidates for NSCL±P.

A Pragmatic Study Shows Failure of Dental Composite Fillings Is Genetically Determined: A Contribution to the Discussion on Dental Amalgams

Composite resins for posterior tooth restorations have become a viable alternative to dental amalgam. Failures sometimes cannot be easily explained, and we hypothesize that a genetic component may influence longevity of restorations. We aimed to determine if there is any evidence for a difference in the performance of amalgams versus composite resin in extensive posterior restorations. We also aimed to determine if risk factors such as age, sex, smoking tobacco, alcohol drinking, diabetes status, and periodontal health status may have a role in the failures of extensive anterior composite restorations. Finally, we investigated if genetic variation in matrix metalloproteinases that are present in the mineralized dentin is associated with failure of composite resin. The data used to perform this research were obtained from the Dental Registry and DNA Repository project after screening 4,856 patients. All restorations were evaluated at times of 1, 2, and 5 years after the restoration placement. 6,266 amalgam and 2,010 composite restorations were analyzed in a total of 807 patients in a period of approximately 10 years (period corresponding to the database existence). An additional 443 extensive direct composite resin restorations in anterior teeth were also studied. Failure rates of amalgam and composite restorations are similar, and by the end of 5 years, composites outperformed amalgams slightly. Failures of anterior composite restorations occurred more often in males who smoked tobacco (p = 0.05), despite a similar number of females and males that smoked tobacco in the sample (116 individuals smoked tobacco, 54 females and 62 males). Alcohol drinking increased failure rate within 2 years (p = 0.03). We found a statistically significant association between matrix metalloproteinase 2 rs9923304 and failure of composite restorations (p = 0.007). Composite resins can replace amalgam restorations. Smoking tobacco and drinking alcohol will increase the chance of restoration failure.

Association of MBL2 Gene Polymorphism with Dental Caries in Saudi Children

The high prevalence of dental caries in children worldwide is a major oral health problem which requires early intervention. Dental caries is mainly caused by the action of acids produced by bacteria in addition to many other factors. Recent genetic studies have reported that a number of genes are associated with the susceptibility to dental caries. The majority of these genes are associated with inflammation, increased susceptibility to infection, and dentine matrix formation. Using the TaqMan assay and direct DNA sequencing, the prevalence of 6 single-nucleotide polymorphisms (SNPs) in MMP9, MBL2, MMP2, and TIMP2 genes was determined in 102 children with caries and in 100 age-matched caries-free controls. Out of the 6 SNPs tested in the 4 selected genes, only rs11003125 in the MBL2 gene was shown to be associated with a high prevalence of caries in our cohort. In addition, haplotype analysis of the 6 SNPs tested revealed that certain haplotypes, namely GT of rs11003125G and rs7501477T and GT of rs7096206G and rs7501477T, were found to be associated with a high prevalence of dental caries in our cohort, while haplotype AG of rs17576A and rs7501477G was found to have a protective effect against dental caries. In conclusion, the data indicate that rs11003125 in the MBL2 gene was shown to be associated with a high prevalence of caries in our cohort, and 2 haplotypes are also involved in the increased susceptibility to dental caries.

Investigation of the effects of estrogen on skeletal gene expression during zebrafish larval head development

The development of craniofacial skeletal structures requires well-orchestrated tissue interactions controlled by distinct molecular signals. Disruptions in normal function of these molecular signals have been associated with a wide range of craniofacial malformations. A pathway mediated by estrogens is one of those molecular signals that plays role in formation of bone and cartilage including craniofacial skeletogenesis. Studies in zebrafish have shown that while higher concentrations of 17-β estradiol (E 2) cause severe craniofacial defects, treatment with lower concentrations result in subtle changes in head morphology characterized with shorter snouts and flatter faces. The molecular basis for these morphological changes, particularly the subtle skeletal effects mediated by lower E 2 concentrations, remains unexplored. In the present study we address these effects at a molecular level by quantitative expression analysis of sets of candidate genes in developing heads of zebrafish larvae treated with two different E 2 concentrations. To this end, we first validated three suitable reference genes, ppia2, rpl8 and tbp, to permit sensitive quantitative real-time PCR analysis. Next, we profiled the expression of 28 skeletogenesis-associated genes that potentially respond to estrogen signals and play role in craniofacial development. We found E 2 mediated differential expression of genes involved in extracellular matrix (ECM) remodelling, mmp2/9/13, sparc and timp2a, as well as components of skeletogenic pathways, bmp2a, erf, ptch1/2, rankl, rarab and sfrp1a. Furthermore, we identified a co-expressed network of genes, including cpn1, dnajc3, esr1, lman1, rrbp1a, ssr1 and tram1 with a stronger inductive response to a lower dose of E 2 during larval head development.

The functional EGF+61 polymorphism and nonsyndromic oral clefts susceptibility in a Brazilian population

Nonsyndromic oral clefts are considered a problem of public health in Brazil, presenting a multifactorial etiology that involves genetic and environmental components, such as maternal alcohol consumption. Several candidate genes have been investigated to identify some association with nonsyndromic clefts risk. The epidermal growth factor (EGF) gene is implicated in the normal craniofacial development and its functional +61 A>G polymorphism has been related to cancer susceptibility. It has been suggested that cancer and oral clefts may share the same molecular pathways.Objective Our goal was to evaluate the association between the EGF+61 A>G polymorphism and nonsyndromic oral clefts susceptibility.Material and Methods The case-control study included 218 cleft cases and 253 controls from Brazil. The control group was comprised of individuals without congenital malformations, dental anomalies and family history of clefts. The cleft phenotypes and subphenotypes were determined based on clinical examination. Genomic DNA was extracted from oral mucosa cells obtained by mouthwash. The EGF+61 A>G polymorphism genotype was determined by polymerase chain reaction-restriction fragment length polymorphism.Results We noticed the association between maternal alcohol consumption during pregnancy and cleft occurrence. The A allele and AA genotype were over-represented in cleft cases compared with control group when we considered the bilateral cleft lip with or without cleft palate (CL±P) cases, cleft cases with tooth agenesis and cleft cases presenting family history of cleft, but the differences were not statistically significant. Contradictorily, the G allele was higher in cleft palate only (CP) cases than in control group, showing a borderline p value. Comparing the different cleft phenotypes, we observed statistical differences between CP and CL±P cases. Our data suggest the EGF+61 A>G polymorphism was not related with nonsyndromic oral clefts susceptibility in a Brazilian population, but supported the different genetic background between CL±P and CP. Moreover, we confirmed the potential effect of maternal alcohol intake on cleft risk in our population.

Crispld2 is required for neural crest cell migration and cell viability during zebrafish craniofacial development

The CAP superfamily member, CRISPLD2, has previously been shown to be associated with nonsyndromic cleft lip and palate (NSCLP) in human populations and to be essential for normal craniofacial development in the zebrafish. Additionally, in rodent models, CRISPLD2 has been shown to play a role in normal lung and kidney development. However, the specific role of CRISPLD2 during these developmental processes has yet to be determined. In this study, it was demonstrated that Crispld2 protein localizes to the orofacial region of the zebrafish embryo and knockdown of crispld2 resulted in abnormal migration of neural crest cells (NCCs) during both early and late time points. An increase in cell death after crispld2 knockdown as well as an increase in apoptotic marker genes was also shown. This data suggests that Crispld2 modulates the migration, differentiation, and/or survival of NCCs during early craniofacial development. These results indicate an important role for Crispld2 in NCC migration during craniofacial development and suggests involvement of Crispld2 in cell viability during formation of the orofacies.

DLX1 and MMP3 contribute to oral clefts with and without positive family history of cancer

OBJECTIVE

It has been suggested that oral clefts and cancer share a common genetic background. This study aimed to investigate the epidemiological and molecular association between oral clefts and cancer.

METHODS

One hundred forty-eight nuclear families with oral clefts and 162 subjects with no birth defect were recruited. Data on self-reported family history of cancer among first, second, and third degree relatives of each patient were collected via a structured questionnaire. We also investigated the association between polymorphisms in the genes AXIN2, BMP2, BMP4, BMP7, DLX1, DLX2, and MMP3 and oral cleft with and without history of cancer. Markers in these genes were genotyped using real time PCR. Chi-square and t-test were used to assess the differences about self-reported family history of cancer between oral cleft and non-cleft individuals. The transmission disequilibrium test (TDT) was used to analyze the distortion of the inheritance of alleles from parents to their affected offspring.

RESULTS

Families with oral clefts had an increased risk of having a family history of cancer (p=0.01; odds ratio=1.79; 95% confidence interval, 1.07-1.87). TDT results showed an association between DLX1 and cleft lip and palate, in which the A allele was undertransmited (p=0.022). For MMP3, G was undertransmited among affected progeny (p=0.019) in cleft palate subgroup.

CONCLUSION

Oral clefts were associated with positive self-reported family history of cancer and with variants in DLX1 and MMP3. The association between oral clefts and cancer raises interesting possibilities to identify risk markers for cancer.

Role of angiogenesis-related genes in cleft lip/palate: review of the literature

OBJECTIVES

Cleft lip and cleft palate (CLP) are the most common congenital craniofacial anomalies. They have a multifactorial etiology and result from an incomplete fusion of the facial buds. Two main mechanisms, acting alone or interacting with each other, were evidenced in this fusion defect responsible for CLP: defective tissue development and/or defective apoptosis in normal or defective tissues. The objective of this work was to study the implication and role of angiogenesis-related genes in the etiology of CL/P.

METHODS

Our methodological approach included a systematic and thorough analysis of the genes involved in CL/P (syndromic and non-syndromic forms) including previously identified genes but also genes that could potentially be angiogenesis-related (OMIM, Pub Med).We studied the interactions of these different genes and their relationships with potential environmental factors.

RESULTS

TGFβ, FGA, PDGFc, PDGFRa, FGF, FGFR1, FGFR2 growth factors as well as MMP and TIMP2 proteolytic enzymes are involved in the genesis of CLP (P>L). Furthermore, 18 genes involved in CLP also interact with angiogenesis-related genes.

DISCUSSION

Even if the main angiogenesis-related genes involved in CLP formation are genes participating in several biological activities and their implication might not be always related to angiogenesis defects, they nevertheless remain an undeniably important research pathway. Furthermore, their interactions with environmental factors make them good candidates in the field of CLP prevention.

Clinical and genetic analysis of a nonsyndromic oligodontia in a child

The etiology of tooth agenesis may be related to several factors, among them, the genetic alterations that play a fundamental role in the development of this dental anomaly, so that knowledge about it helps the clinician to have a greater understanding of their patients. Thus, the aim of this study was to report the case of a nonsyndromic child, with tooth agenesis of one premolar, three first permanent molars, and all second permanent molars. In addition, a genetic research between polymorphic variants in genes MMP3 and BMP2 was performed in order to observe the association between changes in these genes and congenital tooth absences. For this purpose, DNA from child was extracted and polymorphisms were investigated. It was clinically and radiographically observed that this was a case of oligodontia, in which the authors suggested an association between the polymorphisms found and tooth agenesis diagnosed in that child.

Functional Significance of MMP3 and TIMP2 Polymorphisms in Cleft Lip/Palate

Evidence from biological and human studies strongly supports a role for MMP and TIMP genes as candidate genes for non-syndromic cleft lip with or without cleft palate (NSCL/P). We previously showed the association of promoter polymorphisms in MMP3 (rs3025058 and rs522616) and TIMP2 (rs8179096) with NSCL/P. In this study, we examined the functional significance of these polymorphisms. A specific DNA-protein complex for MMP3 rs522616 A was detected, and this allele by itself showed greater promoter activity than the G allele. However, the effect of rs522616 was ultimately regulated by the rs3025058 allele on the background. For TIMP2 rs8179096, the T allele showed a 2.5-fold increase in promoter activity when compared with allele C, whereas both C and T alleles were found to bind to nuclear factor kappa B. Our results provide new evidence that promoter polymorphisms in MMP3 and TIMP2 are functional and may affect gene transcription with possible effects on craniofacial development leading to NSCL/P.

Polymorphic variation within the ADAMTS2, ADAMTS14, ADAMTS5, ADAM12 and TIMP2 genes and the risk of Achilles tendon pathology: a genetic association study

OBJECTIVES

Achilles tendon pathology (ATP) is a multifactorial condition for which genetic risk factors have been identified. The ADAMTS, ADAM12 and TIMP2 genes encode enzymes that are important regulators of tendon homeostasis. ADAMTS2 and ADAMTS14 proteins are procollagen N-propeptidases for pro-collagen type I, type II, and type III. ADAMTS2, like COL5A1, has been linked to Ehlers-Danlos syndrome. Variants within ADAMTS5 and ADAM12 have been associated with osteoarthritis. TIMP2, a metalloprotease inhibitor, maintains homeostasis in the ECM by inhibiting ADAM, ADAMTS and MMP functions. We sought to determine whether single nucleotide polymorphisms (SNPs) within the ADAMTS2, ADAMTS5, ADAMTS14, ADAM12 and TIMP2 genes were associated with the risk of ATP in two independent populations.

DESIGN

213 (115 ATP cases and 98 asymptomatic controls) South African Caucasian participants and 209 (60 ATP cases and 149 asymptomatic controls) Australian Caucasian participants were recruited for this case-control genetic association study.

METHODS

All participants were genotyped using TaqMan technology for the ADAMTS2 rs1054480, ADAMTS5 rs226794, ADAMTS14 rs4747096, ADAM12 rs3740199, and TIMP2 rs4789932 SNPs.

RESULTS

We report for the first time a significant (p=0.016) genotypic association between the TIMP2 rs4789932 variant and ATP in a combined Caucasian cohort. We also identify an interaction between the ADAMTS14 rs4747096 variant and age of onset of ATP (p=0.024).

CONCLUSIONS

Our data show that DNA sequence variation within the TIMP2 gene is a risk factor for ATP in Caucasians. Furthermore, carriage of the ADAMTS14 rs4747096 GG variant appears to delay onset of the injury in the ATP group.

Further evidence of association of the ABCA4 gene with cleft lip/palate

Non-syndromic cleft lip with or without cleft palate (CL/P) is a common birth defect with a complex etiology. Numerous genes and environmental factors, and their interactions, are thought to play a role in the susceptibility to CL/P. A recent genome-wide association study with several populations revealed markers in/near transcription factor vmaf musculoaponeurtoic fibrosarcoma oncogene homolog B (MAFB) and ATP-binding cassette sub-family A member 4 (ABCA4) genes as new susceptibility loci for CL/P. We hypothesized that these genes could also contribute to CL/P in a Brazilian population, and hence we evaluated if the associated single-nucleotide polymorphisms (SNPs) in MAFB (rs13041247 and rs11696257) and ABCA4 (rs560426 and rs481931) were associated with CL/P in our case-control data set. We genotyped 812 Caucasian individuals (400 cases and 412 controls) from Brazil. Allele frequencies were compared for cases and controls as well as for cleft subgroups and controls. ABCA4 rs540426 showed strong associations with CL/P, unilateral and right CL/P, and bilateral CL/P, whereas the SNP rs481931 showed borderline associations with CL/P and bilateral CL/P . No association was found for MAFB. Our results support a potential role for ABCA4 in the etiology of CL/P in individuals from Brazil.