Lower incidence of nonsyndromic cleft lip with or without cleft palate in females: Is homocysteine a factor?

Increased susceptibility for nonsyndromic cleft lip with or without cleft palate by SLC19A1 80G>A genetic variation

BACKGROUND

The disruption of craniofacial developmental pathways during early embryogenesis can lead to conditions such as nonsyndromic cleft lip with or without cleft palate (NSCL/P). Several lines of evidence indicate that inadequate maternal nutrition causes low folate levels during the periconceptional period, resulting in NSCL/P. Although substantial research has been conducted on the possible link between SLC19A1 genetic variants and NSCL/P, the association between SLC19A1 80G>A (rs1051266) and NSCL/P remains unclear. In the present study, the associations of SLC19A1 80G>A with NSCL/P risk were assessed by calculating the pooled odds ratios (ORs) and 95% confidence intervals (CIs) by meta-analyses.

METHODS

Following the PRISMA guidelines, a meta-analysis was conducted on 10 studies assessing the NSCL/P risk associated with SLC19A1 80G>A variant. To ascertain the degree of relationship between the SLC19A1 80G>A genetic variant and the risk of NSCL/P, data were analyzed in allelic, recessive and dominant genetic models. CI of OR for each study and the pooled data were obtained. All statistical analyses were conducted utilizing the MetaGenyo software tool, which integrates the adjustment of P values for multiple testing through the Bonferroni method.

RESULTS

The pooled analysis showed that SLC19A1 80G>A variant significantly increased the NSCL/P risk in the allelic model (OR 1.39; 95% CI 1.00-1.92), recessive model (OR 1.37; 95% CI 1.03-1.82) and dominant models (OR 1.7; 95% CI 1.05-2.90). Publication bias was not observed.

CONCLUSIONS

This study supports that the SLC19A1 80G>A genetic variant is associated with NSCL/P risk.

Co-Occurrence of Taurodontism in Nonsyndromic Cleft Lip and Palate Patients in Subset of Indian Population: A Case-Control Study Using CBCT

The present study aimed to assess the co-occurrence of taurodontism in nonsyndromic cleft lip and palate (NSCLP) patients in a subset of Indian population using cone beam computed tomography (CBCT).

The study was a retrospective case-control kinds assessing 1500 CBCT scans over a period of 2 years; 67 scans out of 1500 showed cleft lip and palate (CLP). After fulfilling the inclusion and exclusion criteria, 38 subjects out of 67 comprised the case group; 80 randomly selected subjects constituted the control group. The first and second permanent molars in both the arches (8 teeth) of each subject were assessed for the presence and severity of taurodontism using the objective criteria. Statistical analysis was done using the χ2 test. Inter and intraobserver agreement was evaluated by Kappa statistics.

71.05% subjects showed taurodontism in case group, while 45% subjects showed its presence in control group; results being significant for both the groups. However, the comparison of number of teeth with taurodontism in the 2 groups came out to be statistically insignificant. Also no significant association of taurodontism was seen with gender or the different types of cleft (P = .437). Hypotaurodontism was the most prevalent type.

There was a higher prevalence of taurodontism in both groups which had been underestimated in the previous studies. This emphasizes the significance of the use of CBCT in detection of dental anomalies which would otherwise go undetected.

Association of Fetal MTHFR 677C > T Polymorphism with Non-Syndromic Cleft Lip with or without Palate Risk: A Systematic Review and Meta-Analysis

This study was conducted to estimate the precise association of fetal MTHFR 677 C > T polymorphism with risk of nonsyndromic cleft lip with or without cleft palate (NSCL ± P) using a large-scale meta-analysis. Methods: A comprehensive literature search was performed using studies published on PubMed, Science Direct, Scopus and CNKI databases up to November 1, 2019. Results: A total of 38 studies with 6,525 children with NSCL ± P and 8,606 controls were selected. Overall, there was a significant association between MTHFR 677 C > T polymorphism and NSCL ± P risk. Subgroup analysis by ethnicity revealed that MTHFR 677 C > T polymorphism contributed to development of NSCL ± P in Caucasian and Mixed populations, but not in Asians. When stratified by country of origin, we found a significant association in Brazilian, Turkish and Indian populations, but not in Chinese and US-American. Conclusions: This meta-analysis provides strong evidence that fetal MTHFR 677 C > T polymorphism is significantly associated with NSCL ± P risk.

Cleft Lip and/or Palate and Associated Risks in Lower-Middle-Income Countries: A Systematic Review

OBJECTIVE

To identify and review published data on the risks associated with cleft lip and/or palate (CL/P) in lower-middle-income countries (LMICs).

DESIGN

A systematic review of literature was performed on electronic databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols. Literature on risks associated with CL/P in LMICs, from 2010 to 2020, were included.

RESULTS

Seventeen studies met the inclusion criteria. All studies adopted an observational study design. Biological and environmental risks were identified. Maternal and paternal age (n = 7) and low socioeconomic status (n = 5) were the most prominently associated environmental risk factors. A strong association was identified between family history of cleft (n = 7) and CL/P occurrence.

CONCLUSION

Environmental risk factors are now being investigated more than biological risk factors in LMICs, aiding health care workers in the early identification of possible cumulative effects of risks in CL/P. Contextually relevant tools are recommended to promote early identification of at-risk infants.

Pharmacogenetic evaluation of 6-mercaptopurine-mediated toxicity in pediatric acute lymphoblastic leukemia patients from a South Indian population

Aim: To evaluate the variants in the genes coding for the proteins involved in thiopurine and folate metabolism with treatment related adverse effects (TRAEs). Materials & methods: Eleven variants in seven candidate genes were genotyped in 127 pediatric acute lymphoblastic leukemia patients under 6-mercaptopurine (6-MP) treatment to infer the association of selected genotypes with TRAEs. Results: Among the genotypes inspected, NUDT15 (c.415C>T) and SLC19A1 (c.80G>A) showed a significant association with the TRAEs (odds ratio = 4.01, p = 0.002 and odds ratio = 7.78, p = 0.002). Conclusion: SLC19A1 and NUDT15 play an important role in the metabolism of 6-MP and it is necessary to spot other variants in associated pathways and investigate the factors that can impact 6-MP metabolism.

SNPs in folate pathway are associated with the risk of nonsyndromic cleft lip with or without cleft palate, a meta-analysis

Background: Prenatal intake of folic acid is important for prevention of NSCL/P (nonsyndromic cleft lip with or without cleft palate). Associated genes in folate pathway are major enzymes of folic acid metabolism that is crucial for preventing birth defects. The present meta-analysis aims to investigate the association between four SNPs in folate pathway genes and the risk of NSCL/P.

Methods: Comprehensive bioinformatics analysis was used to predict the functional pathogenicity of genetic variation. The PubMed, Embase database and Google Scholar were searched by two researchers. Stata 11.0 software was used to analyze the results. Subgroup analysis was carried out to assess the influence of genetic background. Sensitivity analysis, regression analysis and publication analysis were also conducted to enhance the strength of our results.

Results: It is estimated that the probability of two missense mutation rs1801133 in MTHFR and rs1801394 in MTRR are more likely to be damaging by bioinformatics analysis. A significant association between rs1801133 and risk of NSCL/P in two genetic models: TT genotype vs CC genotype (OR = 1.333 95%CI = 1.062–1.674, P = 0.013), and recessive model (OR = 1.325 95%CI = 1.075–1.634, P = 0.008). A significant protective association between rs1801394 GG genotype and NSCL/P in Asian (GG vs AA, OR = 0.520 95%CI = 0.321–0.841, P = 0.008) was observed. Meta-regression, sensitivity analysis, and publication bias analysis confirmed that the results of the present study were statistically significant.

Conclusions: The present study identified that rs1801133 in MTHFR is associated with the risk of NSCL/P, and rs1801394 GG genotype in MTRR play a protective role in Asian. Further, larger studies should be performed to confirm these findings.

Single-nucleotide polymorphisms of methylenetetrahydrofolate reductase gene in a South Indian cohort with nonsyndromic cleft lip with or without palate

Objective:

Clefts of the lip, with or without cleft palate and cleft palate only, collectively called as orofacial clefts (OFCs) are one of the most common congenital malformations with varying degrees of penetrance and phenotype expressions. The aim of this study was to investigate the association between methylenetetrahydrofolate reductase (MTHFR) cytosine-to-thymine (c. 677 C>T), adenine-to-cytosine (c.1298 A>C) single- nucleotide polymorphisms (SNPs) and South Indian patients with the nonsyndromic cleft lip with or without palate (NSCL ± P).

Methods:

A cohort consisting of 25 cases of NSCL ± P and 18 controls from a South Indian cohort were included in this case–control study. Genetic analysis of c.677C>T and c.1298A C polymorphisms in the MTHFR gene was carried out using Sanger sequencing and analyzed from chromatogram profiles. Data interpretation was done using statistical software MedCalc Statistical Software version 16.2 and the Statistical Package for the Social Sciences (SPSS version 22.0).

Results:

DNA sequence analysis of the MTHFR gene revealed c. 677C>T and c. 1298A>C polymorphisms in 16% and 76% of NSCL ± P cases, respectively. Heterozygous variant in MTHFR c. 1298A>C polymorphism was found to be a significant risk factor (P = 0.0164) for NSCL ± P in South Indian ethnic population. c.677C>T polymorphism, in particular, was apparently dormant overall in the study population. These results offer certain novelty in terms of the distinctive pattern in SNPs of genotypes observed in the study.

Conclusion:

NSCL ± P is one of the most common and challenging congenital malformations with complex etiological basis. Common risk factors such as MTHFR SNPs, namely c.677C>T and c.1298A>C, are subjected to variations in terms of ethnic group, geographic region and micro/macro-environmental factors. Overall, our study has explored part of South Indian ethnic population and revealed a different and unique distribution of mutations in this sample population.

A meta-analysis and meta-regression of association between MTHFR A1298C polymorphism and nonsyndromic cleft lip/palate risk: An evaluation based on five genetic models

OBJECTIVE

The present meta-analysis is intended to assess the association between NSCL/P risk and methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism in case-control studies.

MATERIALS AND METHODS

The Web of Science, PubMed/Medline, Scopus, and Cochrane Library databases were searched for related articles published by April 2019. Review Manager 5.3 was applied to measure the odds ratios (ORs) with 95% confidence interval (CI) in the analyses assessing the strength of the association between A1298C polymorphism and NSCL/P risk. Results Sixteen studies were involved and analysed in this meta-analysis. Altogether, the reviewed articles included 2677 NSCL/P patients and 3669 controls. The pooled ORs of the allele, homozygote, heterozygote, dominant, and recessive models were 1.11 (95% CI: 0.94, 1.30; P=0.21), 1.14 (95% CI: 0.94, 1.37; P=0.18), 0.98 (95% CI: 0.80, 1.20; P=0.87), 1.03 (95% CI: 0.86, 1.22; P=0.79), and 1.18 (95% CI: 0.99, 1.41; P=0.07), respectively. The analysis did not identify any significant association between the polymorphism and the risk of NSCL/P in any ethnicity or source of controls.

CONCLUSIONS

This meta-analysis revealed that A1298C polymorphism is not associated with NSCL/P susceptibility, and the subgroup analyses based on ethnicity and the source of cases further confirmed this result.

Methylenetetrahydrofolate reductase C677T polymorphism is not associated with the risk of nonsyndromic cleft lip/palate: An updated meta-analysis

Both genetic and environmental factors affect the risk of orofacial clefts. The present meta-analysis aimed to evaluate the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and risk of nonsyndromic cleft lip/palate (NSCL/P) in cases-control studies. The PubMed/Medline, Scopus, Web of Science, and Cochrane Library databases were searched up to April 2019 with no restrictions. The odds ratios (ORs) and 95% confidence intervals (CIs) in all analyses were calculated by Review Manager 5.3 software. The funnel plot analysis was carried out by the Comprehensive Meta-Analysis version 2.0 software. Subgroup analysis, meta-regression, and sensitivity analysis were performed for the pooled analyses. Thirty-one studies reviewed in this meta-analysis included 4710 NSCL/P patients and 7271 controls. There was no significant association between MTHFR C677T polymorphism and NSCL/P susceptibility related to allelic model (OR = 1.04; P = 0.49), homozygote model (OR = 1.11; P = 0.35), heterozygote model (OR = 0.99; P = 0.91), dominant model (OR = 1.00; P = 0.96), or recessive model (OR = 1.08; P = 0.23). There was no significant association between MTHFR C677T polymorphism and NSCL/P susceptibility based on the ethnicity or the source of cases. There was a significant linear relationship between the year of publication and log ORs for the allele model. The results of the present meta-analysis failed to show an association between MTHFR C677T polymorphism and NSCL/P susceptibility. The subgroup analyses based on the ethnicity and the source of cases further confirmed this result.

Association between RFC1 A80G polymorphism and the susceptibility to nonsyndromic cleft lip with or without cleft palate: a meta-analysis

Background

Reduced folate carrier 1 (RFC1) gene is a candidate for susceptibility to nonsyndromic cleft lip with or without cleft palate (NSCL/P). Association between RFC1 A80G polymorphism and NSCL/P have been studied. The published results are conflicting.

Methods

A meta-analysis of the association between RFC1 A80G polymorphism and NSCL/P was carried out using Stata13.0. A systematic literature search was performed through the PubMed, EMBASE, the Cochrane Library, Web of Science, ScienceDirect, EBSCOhost, China Biology Medicine databases, China National Knowledge Infrastructure and the Wanfang databases. All relevant studies up to 9 September 2019 were identified.

Results

Nine case-control studies including 4,229 total participants (1,334 NSCL/P children, 1,515 healthy children, 656 mothers of the NSCL/P children, and 724 mothers of healthy control children) were included in this study. The meta-analysis revealed that two genetic models of RFC1 A80G polymorphism in NSCL/P children increased risk of NSCL/P: the homozygote model (GG vs. AA, OR =2.346, 95% CI: 1.127-4.884) and the recessive model (GG vs. AG + AA, OR =1.503, 95% CI: 1.049-2.152). Further sensitivity analysis indicated that the frequency of G allele and GG genotype in NSCL/P children was significantly higher than those in the control. However, there was no significant statistical differences after Bonferroni correction. Subgroup analyses indicated the presence of the association of all the model with NSCL/P risk in the Indian children. RFC1 A80G polymorphism in the maternal population of NSCL/P children was not significantly associated with children NSCL/P.

Conclusions

The RFC1 A80G polymorphism was a candidate for susceptibility to NSCL/P in the Indian pediatric population. More studies with larger samples are necessary to reach more conclusive outcomes.

Association between methylenetetrahydrofolate reductase polymorphisms and non-syndromic cleft lip with or without palate susceptibility: an updated systematic review and meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) polymorphisms are thought to be involved in the development of cleft lip with or without cleft palate (NSCL/P), but published results are contradictory. We therefore designed an updated meta-analysis to pool eligible studies and to evaluate further the possible relations between MTHFR polymorphisms (c.677C>T and c.1298A>C) and susceptibility to NSCL/P. A comprehensive search based on PubMed, Medline, Web of Science, and Embase databases was made up to February 2018. Twenty-three case-control and 10 case-parent trio studies (including 1149 cases and 1161 controls) were retrieved. Odds ratio (OR) with 95% CI were used to estimate the pooled strength of association under different genetic models. The Q test and I² test were used to estimate heterogeneity among studies, the quality of which was assessed using the Newcastle-Ottawa scale. In the MTHFR c.677C>T polymorphism group, there were significant overall results for the recessive (OR 1.231, 95%CI 1.092 to 1.387) and homozygote (OR 1.252, 95%CI 1.078 to 1.456) models. Subgroup analysis by subjects and ethnicity identified only associations in European mothers for the recessive model and the homozygote model. For the c.1298A>C group, there were no significant results for either European or Asian patients for all genetic models. The MTHFR c.677C>T polymorphism might increase susceptibility to NSCL/P in European mothers, but was negatively associated in Asian patients, and the MTHFR c.1298A>C polymorphism is not involved in the development of NSCL/P in either European or Asian patients.

Accumulation of rare coding variants in genes implicated in risk of human cleft lip with or without cleft palate

Cleft lip with/without cleft palate (CLP) is a common craniofacial malformation with complex etiologies, reflecting both genetic and environmental factors. Most of the suspected genetic risk for CLP has yet to be identified. To further classify risk loci and estimate the contribution of rare variants, we sequenced the exons in 49 candidate genes in 323 CLP cases and 211 nonmalformed controls. Our findings indicated that rare, protein-altering variants displayed markedly higher burdens in CLP cases at relevant loci. First, putative loss-of-function mutations (nonsense, frameshift) were significantly enriched among cases: 13 of 323 cases (~4%) harbored such alleles within these 49 genes, versus one such change in controls (p = 0.01). Second, in gene-level analyses, the burden of rare alleles showed greater case-association for several genes previously implicated in cleft risk. For example, BHMT displayed a 10-fold increase in protein-altering variants in CLP cases (p = .03), including multiple case occurrences of a rare frameshift mutation (K400 fs). Other loci with greater rare, coding allele burdens in cases were in signaling pathways relevant to craniofacial development (WNT9B, BMP4, BMPR1B) as well as the methionine cycle (MTRR). We conclude that rare coding variants may confer risk for isolated CLP.

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.

[Clinical-epidemiological study in children with cleft lip palate in a secondary-level hospital]

BACKGROUND

One of the most common congenital disorders that affects the facial structures is the cleft lip palate (CLP). The aim of this study was to generate the clinical-epidemiological profile of CLP patients from Hospital de Especialidades del Niño y la Mujer (HENM) Dr. Felipe Nuñez Lara, from the Ministry of Health, Queretaro, Mexico, from 2011 to 2014, who received treatment from the Cleft Lip Palate Clinic in order to provide interdisciplinary treatments for CLP patients based on the information from the pediatric records.

METHODS

Retrospective, cross-sectional, observational study using univariate analysis frequencies for qualitative variables; central statistical and dispersion for quantitative variables and clinical profile. One hundred records were reviewed, from which 15 were discarded for being syndromic cases. Epidemiological, clinical, and socio-demographic variables were studied.

RESULTS

The epidemiological profile (variables associated with mother's pregnancy, patient's health at birth, nutritional and psychomotor development; family medical records, addictions, and socioeconomic factors) and clinical profile (disease classification by sex, structure, and side; surgeries classification and order in which they took place) of the treated population were registered.

CONCLUSIONS

The results showed the need to standardize the data registration on medical records to improve the monitoring and treatment of patients and emphasize actions to maintain low incidence of CLP in Queretaro.

Maternal exposures and risk of oral clefts in South Vietnam

BACKGROUND

Oral clefts are among the most common congenital anomalies. Most studies on risk factors of oral clefts have been carried out in developed countries. We investigated the associations between maternal exposures in the first trimester and oral clefts in South Vietnam.

METHODS

We conducted a hospital-based case-control study during October 2014-November 2015. Cases included 170 patients with nonsyndromic cleft lip with or without cleft palate and those with cleft palate only. Controls were 170 children without oral clefts, matched to each case by age and gender. Mothers were interviewed using structured questionnaire. We performed conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

Passive smoking was associated with increased risk of oral clefts in univariate analysis, but not in multivariable analysis (adjusted OR [aOR] = 1.68; 95% CI, 0.53-5.37). No association was observed between liver intake and oral clefts. Compared with nondrinkers, mothers who reported consumption of caffeine-containing beverages were more likely to have an infant with oral cleft (aOR = 5.89; 95% CI, 1.08-32.00). Periconceptional use of folic acid and multivitamins supplementation was associated with reduced risk of oral clefts (aOR = 0.01; 95% CI, 0.00-0.09 and aOR = 0.03; 95% CI, 0.01-0.13, respectively).

CONCLUSIONS

The results suggest no associations of maternal passive smoking or liver intake with oral clefts. Periconceptional use of folic acid or multivitamins may protect against oral clefts. Further studies are warranted to examine the roles of caffeine consumption in pregnant mothers on occurrence of oral clefts in offspring.

Association of Kaphaja and Kapha-Pittaja Prakriti and methylenetetrahydrofolate reductase C677T allele with type 2 diabetes

Background and Objectives:

Type 2 diabetes is a multifactorial disorder that results from the interaction between genetic predisposition and environmental factors. Different Prakriti (body constitution) individuals have different susceptibility for the diseases, and this Prakriti is determined by both genetic and environmental factor. This study was undertaken to determine the association status of Methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C with type 2 diabetes and Prakriti.

Materials and Methods:

After informed consent, 54 patients with type 2 diabetes and 56 individuals as normal controls were analyzed. Their constitution and pathological data were collected and MTHFR C677T and A1298C genotypes were determined.

Results:

Kapha/Kapha-Pittaja Prakriti were associated and found to be strong risk factors (Chi-square test = 39.67, P < 0.00001, odds ratio [OR] = 16.133, 95% confidence interval [CI] = 6.32–41.20) for type 2 diabetes. MTHFR C677T was associated (Chi-square test = 7.743, P = 0.02) with type 2 diabetes where the major CC genotype was found to be a risk for type 2 diabetes (OR = 3.78, 95% CI = 1.14–12.45). A1298C was not associated with type 2 diabetes (Chi-square test = 2.264, P = 0.322). None of the Prakriti was associated with C677T and A1298C variants.

Interpretation and Conclusion:

In the present study, an extremely strong association between Prakriti (Kaphaja/Kapha-Pittaja) and type 2 diabetes (P < 0.00001) was detected. The present study gives a strong clue for the association of Prakriti (body constitutional) and clinical phenotype.

The study of association between reduced folate carrier 1 (RFC1) polymorphism and non-syndromic cleft lip/palate in Iranian population

Introduction: Cleft lip/palate is one of the most common congenital defects and is supposed to have multifactorial etiology, including a complex interaction between genetics and environment. Reduced folate carrier 1 (RFC1) gene takes part in folate transportation within the cells. In this study, the association of A80G polymorphism in the RFC1 gene with the non-syndromic cleft lip/palate (nsCL/P) was investigated in Iranian infants for the first time. Methods: In this case-control survey, 122 Iranian infants with nsCL/P and 164 healthy infants were investigated for RFC1 polymorphism by PCR and RFLP methods. The results were statistically compared with control group, odds ratios with 95% CI were estimated by univariate and multivariate logistic regression model and a P <0.05 was considered statistically significant. Results: The RFC1 G allele was significantly higher (P=0.001; OR=7, 95% CI: 4.7-10.2) in the cases (60.3%) compared with the controls (17.9%). Not only the RFC1 AG genotype was significantly higher (P<0.001; OR=44, 95% CI: 14.6-133) in cases (67.8%) than the controls (27.4%), but also GG genotype (P<0.001; OR=85, 95% CI: 20.5-352) was much higher in cases (26.4%) than the controls (4.3%). Conclusion: Our study indicated that the RFC1 (A80G) polymorphism was associated with the nsCL/P in Iranian population. Moreover, 80GG homozygosity was significant in the cases. The presence of G allele can be considered as a risk factor for the nsCL/P. Infants with the GG and AG genotypes were more prone to cleft lip/palate as compared to the AA ones. This finding emphasizes the role of RFC1 gene and the intracellular levels of folate.

Strong Association of C677T Polymorphism of Methylenetetrahydrofolate Reductase Gene With Nosyndromic Cleft Lip/Palate (nsCL/P)

Methylenetetrahydrofolate reductase (MTHFR) is essential for DNA biosynthesis and the epigentic process of DNA methylation. It has been reported that abnormal DNA methylation contributes to the pathogenesis of congenital anomalies. There were many published case control studies assessing the associations of MTHFR C677T polymorphism with risks of nosyndromic cleft lip with and without palate (nsCL/P), but with inconsistent results. To derive a more precise estimation of the relationship, a meta-analysis was performed. Eligible articles were identified by search of databases including PubMed, Science Direct, Google Scholar and Springer Link up to December, 2015. Finally, a total of 22 studies with 3724 nsCL/P cases and 5275 controls were included in the present meta-analysis. Odds ratios (ORs) with corresponding 95% confidence intervals (95% CIs) were pooled to assess the association. Subgroup analysis based on ethnicity was also performed. All statistical analyses were done by MIX program. Meta-analysis results suggested that MTHFR C677T polymorphism contributed to the increased nsCL/P risk in overall population using four genetic models except homozygote model (for T vs. C: OR = 1.24, 95% CI = 1.1-1.4; for TT + CT vs. CC: OR = 1.29, 95% CI = 1.04-1.59; for CT vs. CC: OR = 1.26, 95% CI = 0.98-1.63; for TT vs. CC: OR = 1.02, 95% CI = 0.74-1.4; for TT vs. CT + CC: OR = 1.36, 95% CI = 1.05-1.74). In conclusion, results of present meta-analysis suggested that MTHFR C677T polymorphism is significantly associated with nonsyndromic orofacial cleft.

Sequence variation in folate pathway genes and risks of human cleft lip with or without cleft palate

In an effort to comprehensively interrogate genetic variation in the folate pathway for risk of cleft lip with or without cleft palate (CLP), we evaluated 504 common and rare variants in 35 folate-related genes in a panel of 330 infants with CLP and 367 non-malformed controls. Odds ratios (OR) with 95% confidence intervals were computed for common genotypes. A Case-Control Difference metric was calculated for rare variants to highlight differentially occurring alleles. Interactions between variants and a maternal folate intake variable were also evaluated. In gene-only results, significant odds ratios were observed for multiple variants in the BHMT/BHMT2/DMGDH gene cluster, particularly in Hispanic infants. Also in this cluster, rare variant analysis highlighted a substantial case-control difference in BHMT rs60340837 (synonymous Y284Y). In Hispanics, the ALDH1L1 I812V variant (rs4646750) was the most significant risk allele: OR = 3.8 (95%CI = 1.6-9.2) when heterozygous. In non-Hispanic white infants, we observed significant risk for AHCYL2 rs1095423 (homozygous OR = 3.0, 95%CI 1.1-7.8) and the 68 bp CBS insertion (c.844ins68; heterozygous OR = 2.4, 95%CI = 1.1-5.3). Rare variant analysis in this group revealed case-control differences in MTRR and several other methionine cycle genes, a process implicated previously in clefting risk. In women with low folate intake specifically, increased risks were observed for CBS rs2851391 (OR = 3.6, 95%CI = 1.3-9.6) and the R259P nonsynonymous variant of TCN2 (rs1801198; OR = 2.8, 95%CI = 1.2-6.3). This comprehensive study provides further direction on candidate loci to help disentangle the folate-related developmental phenomena in human clefting risk. © 2016 Wiley Periodicals, Inc.

Evaluation of homocysteine levels in individuals having nonsyndromic cleft lip with or without palate

CONTEXT

Nonsyndromic cleft lip with or without palate (NSCL ± P) is a genetic predisposition involving defects in shape and makeup of the lip and palate. Elevation of homocysteine (Hcy) levels is seen in medical complications such as developmental anomalies causing neural tube defects, congenital vascular diseases, neurodegenerative and psychiatric conditions. Evaluation of serum Hcy levels forms an important feature to look further into molecular aspects.

AIMS

The aim of this study was to evaluate the Hcy levels in NSCL ± P cases by comparing with control cases having no orofacial deformities.

SETTINGS AND DESIGN

This study was performed with a biochemical assay in a research laboratory.

MATERIALS AND METHODS

A cross-sectional prevalence study was done to compare the concentrations of Hcy between 25 NSCL ± P patients and 15 healthy controls. Blood samples were collected from both the patients and controls and assessed for serum Hcy level using competent chemiluminescent immunoassay technique.

STATISTICAL ANALYSIS USED

Student's t-test was used for statistical analysis.

RESULTS

The average Hcy concentration was 9.5 μmol/L in control group. There was an increase in Hcy concentration among the NSCL ± P cases with an average value of 18.4 μmol/L. The results were found to be statistically significant using Student's t-test.

CONCLUSIONS

The results of this study indicate that Hcy concentration has a significant elevation in NSCL ± P patients when compared with that of control cases.

Relationship between reduced folate carrier gene polymorphism and non-syndromic cleft lip and palate in Indian population

OBJECTIVE

Folate metabolism involves absorption, transport, modifications and interconversions of folates. The reduced folate carrier does not participate directly in folate metabolism but plays a major role in intracellular transport of metabolically active 5-methyltetrahydrofolate and maintains the intracellular concentrations of folate. The purpose of this study was to identify the prevalence of reduced folate carrier 1 (RFC1) A80G polymorphism and to further delineate its association with non-syndromic cleft lip and palate (NSCLP) in a south Indian population.

METHODS

In the present case-control study, we studied RFC1 gene A80G polymorphism to evaluate its impact on NSCLP risk in south Indian population. Blood samples of 142 cases with NSCLP and 141 controls were collected and genotyped using PCR-RFLP.

RESULTS

The genotype distribution in the control group followed Hardy-Weinberg equilibrium (p = 0.633). The G allele frequency of cases was 64.8% (184/284) and was significantly lower than that found in the control group 56.4% (160/282). The genotype distributions between NSCLP cases and controls was not significantly different (p = 0.131). The allelic model significantly increased the risk of NSCLP (G versus A; OR = 1.40; 95% CI: 1.00-1.97; p = 0.050). In subgroup analysis, the A80G variant showed significant association for the CLP group in dominant and allelic models.

CONCLUSIONS

Altogether, our findings support the hypothesis that RFC1 A80G variant may contribute to NSCLP susceptibility in a south Indian population.

A case-control study of environmental exposures for nonsyndromic cleft of the lip and/or palate in eastern Guangdong, China

OBJECTIVE

To study the relationship between environmental factors and nonsyndromic cleft of the lip and/or palate (NSCLP) in eastern Guangdong for the prevention of NSCLP.

METHODS

A 1:1 retrospective case-control study was carried out. Data from 479 children with NSCLP who accepted comprehensive care in our center were recruited as cases from April 2010 to April 2013. An equal number of controls were recruited from pediatrics during the same period. Then we conducted face-to-face interviews with both parents using a structural questionnaire to identify the relationship between NSCLP and environmental risk factors.

RESULTS

Univariate Chi-square analysis identified 23 factors (P<0.05) as being significantly related to NSCLP. Stepwise multiple logistic regression analyses demonstrated that there were 16 factors significantly associated with this disease. Being male (OR=0.609), parental childbearing age of 25-29 years (ORfather=0.633; ORmother=0.469), higher parental education level (high school or greater) and folic acid supplementation (OR=0.360) were protective factors against NSCLP. However, positive family history of NSCLP (OR=54.132), positive maternal abortion history (OR=3.698), high or low parental age at time of childbirth, poor maternal education level (primary school) (OR=2.258), maternal common cold during pregnancy (OR=1.464), and drug use during pregnancy (OR=3.364) were significant risk factors for NSCLP.

CONCLUSION

The findings are beneficial for researchers to understand the etiology of NSCLP and to lay a solid foundation for the prevention of NSCLP in eastern Guangdong through educational programs to teach parents about the benefits of folic acid supplementation, adequate parental age at childbirth (25-29 years), higher parental education level (high school or higher), and the dangers of common cold and drug use during the first trimester of pregnancy, positive family history and maternal abortion history.

The Prevalence of Factor V Leiden (G1691A) and Methylenetetrahydrofolate Reductase C677T Mutations in Sickle Cell Disease in Western India

The prevalence of the Factor V Leiden (FVL; G1691A) mutation and the methylenetetrahydrofolate reductase (MTHFR; C677T) mutation was determined in 180 patients with sickle cell (SS) disease (126 sickle homozygous and 54 sickle β-thalassaemia—age 1-47 years) and in 130 healthy controls. The FVL mutation in the heterozygous state was present in only 3 patients with SS disease and was absent in the controls. Genotyping of MTHFR 677C > T revealed increased frequency of the C allele than the T allele in patients as well as in controls. This suggests that these genetic markers may not be major risk factors for a hypercoagulable state in Indian patients with SS disease.

Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and susceptibility to gastric adenocarcinoma in an Italian population

Objective

Several studies have reported the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms and nonsyndromic cleft lip with or without palate (NSCL/P) in Asian populations. However, findings have been conflicting. In order to investigate the association, a meta-analysis was performed.

Methods

We searched Pubmed, MedLine and EmBase database to selected eligible studies. The pooled odds ratios (ORs) with 95% confidence intervals (95%CIs) were calculated using fixed effects model or random effects model to assess the association between MTHFR polymorphisms and NSCL/P in both Asian children and mothers.

Results

Finally, nine case-control studies were included. Overall, the MTHFR C677T polymorphism and NSCL/P showed pooled ORs (95%CI) of 1.41(1.23–1.61) in Asian children, and 1.70(1.19–2.42) in Asian mothers. Subgroup analyses by geographical locations further identified the association in Eastern Asian children, Western/Central Asian children and mothers, but not in Eastern Asian mothers. However, no significant relationship between MTHFR A1298C polymorphism and NSCL/P was found in this meta-analysis.

Conclusions

The MTHFR 677T allele was associated with an increased risk of NSCL/P in Asian populations.