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Slavec L, Karas Kuželički N, Locatelli I, Geršak K. Genetic markers for non-syndromic orofacial clefts in populations of European ancestry: a meta-analysis. Sci Rep 2022; 12:1214. [PMID: 35075162 PMCID: PMC8786890 DOI: 10.1038/s41598-021-02159-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 11/10/2021] [Indexed: 11/25/2022] Open
Abstract
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.
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Affiliation(s)
- Lara Slavec
- University Medical Centre Ljubljana, Division of Gynaecology and Obstetrics, Research Unit, Ljubljana, Slovenia.,University of Ljubljana, Faculty of Pharmacy, Department of Clinical Biochemistry, Ljubljana, Slovenia
| | - Nataša Karas Kuželički
- University of Ljubljana, Faculty of Pharmacy, Department of Clinical Biochemistry, Ljubljana, Slovenia
| | - Igor Locatelli
- University of Ljubljana, Faculty of Pharmacy, Department of Social Pharmacy, Ljubljana, Slovenia
| | - Ksenija Geršak
- University Medical Centre Ljubljana, Division of Gynaecology and Obstetrics, Research Unit, Ljubljana, Slovenia. .,University of Ljubljana, Faculty of Medicine, Department of Gynaecology and Obstetrics, Ljubljana, Slovenia.
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2
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Amooee A, Dastgheib SA, Niktabar SM, Noorishadkam M, Lookzadeh MH, Mirjalili SR, Heiranizadeh N, Neamatzadeh H. Association of Fetal MTHFR 677C > T Polymorphism with Non-Syndromic Cleft Lip with or without Palate Risk: A Systematic Review and Meta-Analysis. Fetal Pediatr Pathol 2021; 40:337-353. [PMID: 31880477 DOI: 10.1080/15513815.2019.1707918] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
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.
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Affiliation(s)
- Abdolhamid Amooee
- Department of Surgery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Seyed Alireza Dastgheib
- Department of Medical Genetics, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | | | - Mahmood Noorishadkam
- Department of Pediatrics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Mother and Newborn Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Mohamad Hosein Lookzadeh
- Department of Pediatrics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Mother and Newborn Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Seyed Reza Mirjalili
- Department of Pediatrics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Mother and Newborn Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Naeimeh Heiranizadeh
- Department of Surgery, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Hossein Neamatzadeh
- Mother and Newborn Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Department of Medical Genetics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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3
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SNPs in folate pathway are associated with the risk of nonsyndromic cleft lip with or without cleft palate, a meta-analysis. Biosci Rep 2021; 40:222276. [PMID: 32124929 PMCID: PMC7080646 DOI: 10.1042/bsr20194261] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/18/2020] [Accepted: 02/28/2020] [Indexed: 12/18/2022] Open
Abstract
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.
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4
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Abdulla R, Kudkuli J, Kapoor S, Prabhu V, Shetty P, Aziz NZ. Single-nucleotide polymorphisms of methylenetetrahydrofolate reductase gene in a South Indian cohort with nonsyndromic cleft lip with or without palate. J Oral Maxillofac Pathol 2021; 24:453-458. [PMID: 33967480 PMCID: PMC8083445 DOI: 10.4103/jomfp.jomfp_329_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2019] [Revised: 06/03/2020] [Accepted: 07/30/2020] [Indexed: 12/04/2022] Open
Abstract
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.
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Affiliation(s)
- Riaz Abdulla
- Department of Oral Pathology and Microbiology, Yenepoya Dental College, Yenepoya (Deemed to be University), Mangalore, Karnataka, India.,Department of Biomaterials and Research Centre, Yenepoya Dental College, Yenepoya (Deemed to be University), Mangalore, Karnataka, India
| | - Jagadish Kudkuli
- Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka, India
| | - Saketh Kapoor
- Stem Cells and Regenerative Medicine Centre, Yenepoya (Deemed to be University), Mangalore, Karnataka, India
| | - Vishnudas Prabhu
- Department of Oral Pathology and Microbiology, Yenepoya Dental College, Yenepoya (Deemed to be University), Mangalore, Karnataka, India
| | - Pushparaja Shetty
- Department of Oral Pathology, A B Shetty Memorial Institute of Dental Sciences, NITTE (Deemed to be University), Mangalore, Karnataka, India
| | - Niloufa Z Aziz
- Department of Oral Pathology, Century International Institute of Dental Sciences, Poinachi, Kerala, India
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5
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Zhou Y, Sinnathamby V, Yu Y, Sikora L, Johnson CY, Mossey P, Little J. Folate intake, markers of folate status and oral clefts: An updated set of systematic reviews and meta-analyses. Birth Defects Res 2020; 112:1699-1719. [PMID: 33118705 DOI: 10.1002/bdr2.1827] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 10/04/2020] [Accepted: 10/11/2020] [Indexed: 12/17/2022]
Abstract
BACKGROUND There has been a longstanding debate about the role of folate in the etiology of orofacial clefts (OFCs). Studies of different measures of nutritional intake or folate status have been done to investigate the possible role of folate in the prevention of OFC. Only one knowledge synthesis has attempted to bring together different types of evidence. The aim of the present work was to update it. METHODS Evidence for associations between OFC and dietary folate, supplement use, folic acid fortification, biomarkers of folate status, and variants of MTHFR (C677T and A1298C) were included. Potentially eligible articles were systematically identified from PubMed, Medline, Embase, and Web of Science (2007-2020) and combined using random-effects meta-analysis when appropriate. Quality assessments were conducted using the Newcastle-Ottawa scale and Cochrane's risk of bias tool. RESULTS Sixty-four studies published since the previous knowledge synthesis were identified, with eight of these identified through a supplementary search from October, 2018 to August, 2020. There was an inverse association between folic acid-containing supplement use before or during pregnancy and cleft lip with or without cleft palate (CL/P) (OR 0.60, 95% CI 0.51-0.69), with considerable between-study heterogeneity. The prevalence of CL/P showed a small decline post-folic acid fortification in seven studies (OR 0.94, 95% CI 0.86-1.02). No association was found between OFC and genetic markers of folate status. The coronavirus-19 pandemic has threatened food availability globally and therefore there is a need to maintain and even enhance surveillance concerning maternal intake of folate and related vitamins. CONCLUSIONS The risk of non-syndromic OFC was reduced among pregnant women with folic acid-containing supplements during the etiologically relevant period. However, high heterogeneity between included studies, incomplete reporting of population characteristics and variation in timing of exposure and supplement types mean that conclusions should be drawn with caution.
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Affiliation(s)
- Yulai Zhou
- School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ontario, Canada
| | | | - Yamei Yu
- School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ontario, Canada
| | - Lindsey Sikora
- Health Sciences Library, University of Ottawa, Ontario, Canada
| | - Candice Y Johnson
- Department of Family Medicine and Community Health, Duke University, Durham, North Carolina, USA
| | - Peter Mossey
- School of Dentistry, University of Dundee, Dundee, Scotland.,WHO Collaborating Centre for Craniofacial Anomalies, Dundee, Scotland
| | - Julian Little
- School of Epidemiology and Public Health, Faculty of Medicine, University of Ottawa, Ontario, Canada
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6
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Lakkakula BV, Sengupta S, Agrawal J, Singh S, Mendhey P, Jangde P, Sharma A, Pande PA, Krishan P, Shukla P, Momin S, Nagaraju GP, Pattnaik S. Maternal and infant MTHFR gene polymorphisms and non-syndromic oral cleft susceptibility: An updated meta-analysis. Process Biochem 2020. [DOI: 10.1016/j.procbio.2019.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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7
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Imani MM, Golchin N, Safaei M, Rezaei F, Abbasi H, Sadeghi M, Lopez-Jornet P, Mozaffari HR, Sharifi R. Methylenetetrahydrofolate reductase C677T polymorphism is not associated with the risk of nonsyndromic cleft lip/palate: An updated meta-analysis. Sci Rep 2020; 10:1531. [PMID: 32001764 PMCID: PMC6992667 DOI: 10.1038/s41598-020-58357-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 12/18/2019] [Indexed: 11/08/2022] Open
Abstract
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.
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Affiliation(s)
- Mohammad Moslem Imani
- Department of Orthodontics, School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
| | - Negin Golchin
- Students Research Committee, Kermanshah University of Medical Sciences, Kermanshah, 6715847141, Iran
| | - Mohsen Safaei
- Advanced Dental Sciences Research Laboratory, School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
| | - Farzad Rezaei
- Department of Oral and Maxillofacial Surgery, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
| | - Hooshyar Abbasi
- Department of Oral and Maxillofacial Surgery, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
| | - Masoud Sadeghi
- Medical Biology Research Center, Kermanshah University of Medical Sciences, Kermanshah, 6714415185, Iran.
| | - Pia Lopez-Jornet
- Facultad de Medicina y Odontologia Universidad de Murcia, Hospital Morales Meseguer, Clinica Odontologic Adv Marques Velez s/n, 30008, Murcia, Spain
| | - Hamid Reza Mozaffari
- Department of Oral and Maxillofacial Medicine, School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
| | - Roohollah Sharifi
- Department of Endodontics, School of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, 6713954658, Iran
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8
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Shu X, Shu S, Yang L. Association between methylenetetrahydrofolate reductase polymorphisms and non-syndromic cleft lip with or without palate susceptibility: an updated systematic review and meta-analysis. Br J Oral Maxillofac Surg 2019; 57:819-830. [PMID: 31303355 DOI: 10.1016/j.bjoms.2019.06.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 06/17/2019] [Indexed: 02/05/2023]
Abstract
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.
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Affiliation(s)
- X Shu
- Cleft Lip and Palate Treatment Center, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - S Shu
- Cleft Lip and Palate Treatment Center, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - L Yang
- Cleft Lip and Palate Treatment Center, Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
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9
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Assis Machado R, de Toledo IP, Martelli-Júnior H, Reis SR, Neves Silva Guerra E, Coletta RD. Potential genetic markers for nonsyndromic oral clefts in the Brazilian population: A systematic review and meta-analysis. Birth Defects Res 2018; 110:827-839. [DOI: 10.1002/bdr2.1208] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 01/10/2018] [Accepted: 01/22/2018] [Indexed: 12/29/2022]
Affiliation(s)
- Renato Assis Machado
- Department of Oral Diagnosis, School of Dentistry; University of Campinas; Piracicaba SP Brazil
| | - Isabela Porto de Toledo
- Laboratory of Oral Histopathology, Health Sciences Faculty; University of Brasília; Brasília DF Brazil
| | | | | | - Eliete Neves Silva Guerra
- Laboratory of Oral Histopathology, Health Sciences Faculty; University of Brasília; Brasília DF Brazil
| | - Ricardo D. Coletta
- Department of Oral Diagnosis, School of Dentistry; University of Campinas; Piracicaba SP Brazil
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10
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Rai V. Strong Association of C677T Polymorphism of Methylenetetrahydrofolate Reductase Gene With Nosyndromic Cleft Lip/Palate (nsCL/P). Indian J Clin Biochem 2017; 33:5-15. [PMID: 29371764 DOI: 10.1007/s12291-017-0673-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 06/23/2017] [Indexed: 02/07/2023]
Abstract
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.
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Affiliation(s)
- Vandana Rai
- Human Molecular Genetics Laboratory, Department of Biotechnology, VBS Purvanchal University, Jaunpur, 222003 India
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11
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Ramírez-Chau C, Blanco R, Colombo A, Pardo R, Suazo J. MTHFRc.677C>T is a risk factor for non-syndromic cleft lip with or without cleft palate in Chile. Oral Dis 2016; 22:703-8. [DOI: 10.1111/odi.12533] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/15/2016] [Accepted: 07/02/2016] [Indexed: 11/29/2022]
Affiliation(s)
- C Ramírez-Chau
- Instituto de Investigación en Ciencias Odontológicas; Facultad de Odontología; Universidad de Chile; Santiago Chile
| | - R Blanco
- Programa de Genética Humana; Instituto de Ciencias Biomédicas; Facultad de Medicina; Universidad de Chile; Santiago Chile
| | - A Colombo
- Programa de Anatomía y Biología del Desarrollo; Instituto de Ciencias Biomédicas; Facultad de Medicina; Universidad de Chile; Santiago Chile
- Servicio de Anatomía Patológica; Hospital Clínico de la Universidad de Chile; Santiago Chile
| | - R Pardo
- Sección de Genética; Hospital Clínico Universidad de Chile; Santiago Chile
- Unidad de Neonatología; Hospital Clínico Universidad de Chile; Santiago Chile
- Unidad de Genética; Hospital Dr. Sótero del Río; Santiago Chile
| | - J Suazo
- Instituto de Investigación en Ciencias Odontológicas; Facultad de Odontología; Universidad de Chile; Santiago Chile
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12
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de Aguiar PKF, Coletta RD, de Oliveira AMLF, Machado RA, Furtado PGC, de Oliveira LA, de Aquino SN, Martelli-Junior H, de Almeida Reis SR, Moreira HSB, Persuhn DC. rs1801133C>T polymorphism inMTHFRis a risk factor for nonsyndromic cleft lip with or without cleft palate in the Brazilian population. ACTA ACUST UNITED AC 2015; 103:292-8. [DOI: 10.1002/bdra.23365] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
| | - Ricardo D. Coletta
- Department of Oral Diagnosis; School of Dentistry; State University of Campinas; Piracicaba São Paulo Brazil
| | | | - Renato Assis Machado
- Department of Oral Diagnosis; School of Dentistry; State University of Campinas; Piracicaba São Paulo Brazil
| | | | | | | | - Hercilio Martelli-Junior
- Stomatology Clinic; Dental School; State University of Montes Claros; Montes Claros Minas Gerais Brazil
- Center for Rehabilitation of Craniofacial Anomalies; Dental School; University of José Rosario Vellano; Alfenas Minas Gerais Brazil
| | | | | | - Darlene Camati Persuhn
- Molecular Biology Department - Federal University of Paraíba; João Pessoa Paraíba Brazil
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13
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Pan X, Wang P, Yin X, Liu X, Li D, Li X, Wang Y, Li H, Yu Z. Association between Maternal MTHFR Polymorphisms and Nonsyndromic Cleft Lip with or without Cleft Palate in Offspring, A Meta-Analysis Based on 15 Case-Control Studies. INTERNATIONAL JOURNAL OF FERTILITY & STERILITY 2015; 8:463-80. [PMID: 25780529 PMCID: PMC4355933 DOI: 10.22074/ijfs.2015.4186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Accepted: 11/25/2013] [Indexed: 11/30/2022]
Abstract
Background The methylenetetrahydrofolate reductase (MTHFR) is thought to be
involved in the development of nonsyndromic cleft lip with or without cleft palate
(NSCL/P). However, conflicting results have been obtained when evaluating the association between maternal MTHFR C677T and A1298C polymorphisms and the risk of
NSCL/P. In light of this gap, a meta-analysis of all eligible case-control studies was
conducted in the present study. Materials and Methods A total of 15 case-control studies were ultimately identified
after a comprehensive literature search and Hardy-Weinberg equilibrium (HWE) examination. Cochrane’s Q test and index of heterogeneity (I2) indicated no obvious heterogeneity among studies. Results Fixed or random-effects models were used to calculate the pooled odds ratios
(ORs). The results showed that the TT genotype in mothers increased the likelihood of having
NSCL/P offspring 1.25 times (95% CI: 1.047-1.494) more than the CC homozygotes. Meanwhile, maternal TT genotype increased the risk of producing NSCL/P offspring in recessive
model (OR=1.325, 95% CI: 1.124-1.562). However, the CT heterozygote and the CT+TT
dominant models had no association with NSCL/P offspring compared with the CC wild-type
homozygote model. Subgroup analyses based on ethnicity indicated that maternal TT genotype increased the likelihood of having NSCL/P offspring in Whites (OR=1.308, 95% CI:
1.059-1.617) and Asians (OR=1.726, 95% CI: 1.090-2.733) in recessive model. Also, subgroup analyses based on source of control showed that mothers with the 677TT genotype had
a significantly increased susceptibility of having NSCL/P children in hospital based population (HB) when compared with CC homozygotes (OR=1.248, 95% CI: 1.024-1.520) and un-
der the recessive model (OR=1.324, 95% CI: 1.104-1.588). Furthermore, maternal A1298C
polymorphism had no significant association with producing NSCL/P offspring (dominant
model OR=0.952, 95% CI: 0.816-1.111, recessive model OR=0.766, 95% CI: 0.567-1.036). Conclusion MTHFR C677T polymorphism is associated with the risk of generating NSCL/P
offspring, and being a 677TT homozygote is a risk factor. MTHFR A1298C polymorphism
was not associated with generating NSCL/P offspring. However, further work should be performed to confirm these findings.
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Affiliation(s)
- Xinjuan Pan
- College of Public Health, Zhengzhou University, Zhengzhou, China ; Medical College, Henan University of Science and Technology, Luoyang, China
| | - Ping Wang
- Medical College, Henan University of Science and Technology, Luoyang, China
| | - Xinjuan Yin
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Xiaozhuan Liu
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Di Li
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Xing Li
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Yongchao Wang
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Hongle Li
- College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Zengli Yu
- College of Public Health, Zhengzhou University, Zhengzhou, China
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14
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Li Z, Jun Y, Zhong-Bao R, Jie L, Jian-Ming L. Association between MTHFR C677T polymorphism and congenital heart disease. A family-based meta-analysis. Herz 2014; 40 Suppl 2:160-7. [PMID: 25256053 DOI: 10.1007/s00059-014-4144-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/23/2014] [Indexed: 12/22/2022]
Abstract
Congenital heart disease (CHD) is the most common type of birth defect. It is suspected that polymorphisms in folate metabolism are associated with an increased risk of CHD, but the conclusion remains unclear. Studies have reported that the MTHFR C677T polymorphism was associated with the development of structural congenital heart malformations. The objective of this study was to conduct a meta-analysis of available studies to identify common polymorphisms in the MTHFR gene in children with CHD and their mothers and to test for an association between genotype and disease. In all, 19 eligible studies comprising 4,219 cases and 20,123 controls were included in this meta-analysis. A significant association was found between the MTHFR C677T polymorphism and CHD risk (OR: 1.26; 95 % CI = 1.06-1.51; p = 0.009) with no strong evidence of heterogeneity (I(2) = 39 %) in the fetal analysis. In the maternal analysis, the MTHFR C677T polymorphism was significantly associated with CHD risk (OR = 1.52; 95 % CI = 1.09-2.11; p = 0.01) with significant heterogeneity (I(2) = 63 %).
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Affiliation(s)
- Z Li
- Department of Cardiology, Institute of Medical Research, Taizhou People's Hospital, Yingchun Road 210, 225300, Taizhou, Jiangsu Province, China
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15
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Desai AL, Dinesh MR, Amarnath BC, Dharma RM, Akshai KR, Prashanth CS. Association of Transforming Growth Factor Alpha and Methylenetetrahydrofolate reductase gene variants with nonsyndromic cleft lip and palate in the Indian population. Contemp Clin Dent 2014; 5:329-33. [PMID: 25191068 PMCID: PMC4147808 DOI: 10.4103/0976-237x.137932] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objectives: The aim was to evaluate the relationship of the K-primer variant of the transforming growth factor-alpha (TGF-α) gene and C677T variant of the methylenetetrahydrofolate reductase (MTHFR) gene with nonsyndromic cleft lip and palate (CL/P) in the Indian population. Setting and Sample Population: The study group consisted of DNA samples of 25 subjects with nonsyndromic CL with or without cleft palate and 25 unrelated controls, already existing in the Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India. Materials and Methods: The DNA samples were divided into two categories: Group A which included the 25 subjects with nonsyndromic CL/P; and Group B, which consisted of the 25 unrelated controls. The polymerase chain reaction (PCR) test was done for amplification of the region of interest from the DNA samples. Restriction digestion was then performed on the amplified product using the restriction enzyme HinfI, separately for each of the variants. The digested PCR products were separated into channels on a 1.5% agarose gel containing ethidium bromide in an electrophoretic chamber. A U.V. transilluminator was used to see the specific bands of base pairs of the digested PCR products. Results: In Group A, the TGF-α gene variant was present in 16 subjects (P = 0.001) and MTHFR gene variant was present in 8 subjects (P = 0.185). A combination of both gene variants were present in seven subjects, which was an interesting finding. In Group B, four subjects tested positive for the TGF-α and MTHFR gene variants. Conclusions: The TGF-α gene variant and a combination of TGF-α + MTHFR gene variants significantly contribute to the development of nonsyndromic CL/P and can be considered as genetic markers for Indian population. The MTHFR gene variant, though a minor risk factor, cannot be considered as a genetic marker.
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Affiliation(s)
- Asavari L Desai
- Department of Orthodontics, Manipal College of Dental Sciences, Mangalore, Karnataka, India
| | - M R Dinesh
- Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India
| | - B C Amarnath
- Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India
| | - R M Dharma
- Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India
| | - K R Akshai
- Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India
| | - C S Prashanth
- Department of Orthodontics, D.A.P.M.R.V. Dental College, Bengaluru, Karnataka, India
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16
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MTHFR C677T and A1298C polymorphisms and risk of nonsyndromic orofacial clefts in a south Indian population. Int J Pediatr Otorhinolaryngol 2014; 78:339-42. [PMID: 24380661 DOI: 10.1016/j.ijporl.2013.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 10/30/2013] [Accepted: 12/05/2013] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Several lines of evidence suggest that the decrease in folate in periconceptional period or maternal use of folate antagonists has been associated with a higher risk of orofacial clefts (OFCs). MTHFR is a critical enzyme in folate metabolism that catalyzes the irreversible conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, thus playing a vital role in DNA synthesis and DNA methylation. The aim of our study was to determine whether there is any association between the susceptibility to Nonsyndromic cleft lip with or without cleft palate (NSCL/P) amongst the variations of MTHFR genotypes in South Indian population. METHODS Our sample comprised 123 cases with NSCL/P and 141 controls without clefts or family history of clefting. The most common polymorphisms C677T (rs1801133) and A1298C (rs1801131) on the MTHFR gene were screened for the genotypes using PCR-RFLP. RESULTS Both C677T and A1298C are polymorphic with minor allele frequencies of 0.131 and 0.429, respectively, for controls. Genotype data in control and cleft groups are following the Hardy Weinberg Equilibrium. There were no significant differences in genotypes of both polymorphisms between controls and NSCL/P. The pairwise LD values (D' and r(2)) between C677T and A1298C are 1.0 and 0.096 respectively indicating no significant LD between these two SNPs. Haplotype phenotype analysis did not show the evidence for association. Gene-gene interaction showed the distribution of the observed combinations of the two MTHFR polymorphisms was not different between NSCL/P and controls (p=0.887). CONCLUSIONS Our results do not support the hypothesis, that variants in the MTHFR gene confer a risk for NSCL/P in the South Indian population.
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17
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Wehby GL, Goco N, Moretti-Ferreira D, Felix T, Richieri-Costa A, Padovani C, Queiros F, Guimaraes CVN, Pereira R, Litavecz S, Hartwell T, Chakraborty H, Javois L, Murray JC. Oral cleft prevention program (OCPP). BMC Pediatr 2012. [PMID: 23181832 PMCID: PMC3532199 DOI: 10.1186/1471-2431-12-184] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Background Oral clefts are one of the most common birth defects with significant medical, psychosocial, and economic ramifications. Oral clefts have a complex etiology with genetic and environmental risk factors. There are suggestive results for decreased risks of cleft occurrence and recurrence with folic acid supplements taken at preconception and during pregnancy with a stronger evidence for higher than lower doses in preventing recurrence. Yet previous studies have suffered from considerable design limitations particularly non-randomization into treatment. There is also well-documented effectiveness for folic acid in preventing neural tube defect occurrence at 0.4 mg and recurrence with 4 mg. Given the substantial burden of clefting on the individual and the family and the supportive data for the effectiveness of folic acid supplementation as well as its low cost, a randomized clinical trial of the effectiveness of high versus low dose folic acid for prevention of cleft recurrence is warranted. Methods/design This study will assess the effect of 4 mg and 0.4 mg doses of folic acid, taken on a daily basis during preconception and up to 3 months of pregnancy by women who are at risk of having a child with nonsyndromic cleft lip with/without palate (NSCL/P), on the recurrence of NSCL/P. The total sample will include about 6,000 women (that either have NSCL/P or that have at least one child with NSCL/P) randomly assigned to the 4 mg and the 0.4 mg folic acid study groups. The study will also compare the recurrence rates of NSCL/P in the total sample of subjects, as well as the two study groups (4mg, 0.4 mg) to that of a historical control group. The study has been approved by IRBs (ethics committees) of all involved sites. Results will be disseminated through publications and presentations at scientific meetings. Discussion The costs related to oral clefts are high, including long term psychological and socio-economic effects. This study provides an opportunity for huge savings in not only money but the overall quality of life. This may help establish more specific clinical guidelines for oral cleft prevention so that the intervention can be better tailored for at-risk women. ClinicalTrials.gov Identifier NCT00397917
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18
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Prasad VS, Shivani V. Genetic significance of muscle segment homeo box1 gene in South Indian population for cleft lip and palate. INDIAN JOURNAL OF HUMAN GENETICS 2012; 18:332-9. [PMID: 23716942 PMCID: PMC3656523 DOI: 10.4103/0971-6866.107988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Oral clefts having a prehistoric existence and the latest scientific technologies have shown new insights in identifying the cause and management. So this is a DNA/gene based study has been presented in this article which comprises the significance of MSX1 gene in cleft samples of major states of South India. AIMS To evaluate the significance of MSX1 gene in South Indian population having cleft lip and palate. SETTINGS AND DESIGN Four states of native population were set for the study. From each state renowned cleft operating center was selected with the prior ethical and suitable permission and patient consent was taken. Blood samples were collected from each effected sibling were studied and their details were coded. The collected blood samples were used for DNA isolation, PCR amplification and sequencing. MATERIALS AND METHODS Eighty patients with non-syndromic CL/CLP/CP from various cleft operating centers in southern states (Karnataka, Tamilnadu, Kerala and Andhra Pradesh) with different ethnic/cultural background were taken. Twenty samples (families) were collected from each state and sequenced and compared with earlier data. RESULTS Analysis of this study indicates that mutation of either G273A/C or C102G seems to cause cleft formation. In this analysis, we found a novel mutation (414G to T) which is submitted to NCBI Gene data bank (EF065625). CONCLUSION This study supports MSX1 gene leading to cleft lip and palate in the samples studied.
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Affiliation(s)
- Venkanna S Prasad
- Department of Oral and Maxillofacial Surgery, Government Dental College, Bangalore, Karnataka, India
| | - Venkatesh Shivani
- Department of Oral and Maxillofacial Surgery, Government Dental College, Bangalore, Karnataka, India
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19
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Pan Y, Zhang W, Ma J, Du Y, Li D, Cai Q, Jiang H, Wang M, Zhang Z, Wang L. Infants'MTHFRpolymorphisms and nonsyndromic orofacial clefts susceptibility: A meta-analysis based on 17 case-control studies. Am J Med Genet A 2012; 158A:2162-9. [DOI: 10.1002/ajmg.a.35503] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 05/07/2012] [Indexed: 11/09/2022]
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20
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Tsai SJ, Hong CJ, Yeh HL, Liou YJ, Yang AC, Liu ME, Hwang JP. Heterozygote advantage of the MTHFR C677T polymorphism on specific cognitive performance in elderly Chinese males without dementia. Dement Geriatr Cogn Disord 2012; 32:159-63. [PMID: 21997345 DOI: 10.1159/000333074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/29/2011] [Indexed: 11/19/2022] Open
Abstract
AIMS Aging is associated with cognitive deterioration, and genetic factors are implicated in individual cognitive differences in the aged. The C677T mutation in the 5,10-methylenetetrahydrofolate reductase gene (MTHFR) yields a common thermolabile variant (T) with reduced enzyme activity and consequent elevation of serum homocysteine concentrations. We designed the present study to investigate whether this functional polymorphism may affect global and specific cognitive functions in older Chinese males without dementia. METHODS The subjects included 356 elderly males without major psychiatric disorders or dementia, who were assessed by the Cognitive Abilities Screening Instruments (CASI) and the Wechsler Digit Span Task tests. RESULTS A significant association was found between the MTHFR C677T polymorphism and total CASI scores (p = 0.012), particularly in short-term memory (p = 0.002) and concentration/mental manipulation (p = 0.007). Post hoc tests indicated that the C/T heterozygotes achieved better cognitive function test results than C/C or T/T carriers. No association was found between the MTHFR genotype and the Wechsler Digit Span Task tests. CONCLUSION These results suggest that a heterozygote advantage exists for the MTHFR C677T polymorphism in specific cognitive functions in elderly Chinese males without dementia.
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Affiliation(s)
- Shih-Jen Tsai
- Department of Psychiatry, Taipei Veterans General Hospital, Taiwan, ROC
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21
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Luo YL, Cheng YL, Ye P, Wang W, Gao XH, Chen Q. Association between MTHFR polymorphisms and orofacial clefts risk: A meta-analysis. ACTA ACUST UNITED AC 2012; 94:237-44. [DOI: 10.1002/bdra.23005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 02/01/2012] [Accepted: 02/08/2012] [Indexed: 01/06/2023]
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Bhaskar L, Murthy J, Venkatesh Babu G. Polymorphisms in genes involved in folate metabolism and orofacial clefts. Arch Oral Biol 2011; 56:723-37. [DOI: 10.1016/j.archoralbio.2011.01.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 01/18/2011] [Accepted: 01/18/2011] [Indexed: 11/24/2022]
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Abstract
Nonsyndromic cleft lip and palate is a complex genetic disorder with variable phenotype, largely attributed to the interactions of the environment and multiple genes, each potentially having certain effects. Numerous genes have been reported in studies demonstrating associations and/or linkage of the cleft lip and palate phenotypes to alleles of microsatellite markers and single nucleotide polymorphisms within specific genes that regulate transcription factors, growth factors, cell signalling and detoxification metabolisms. Although the studies reporting these observations are compelling, most of them lack statistical power. This review compiles the evidence that supports linkage and associations to the various genetic loci and candidate genes. Whereas significant progress has been made in the field of cleft lip and palate genetics in the past decade, the role of the genes and genetic variations within the numerous candidate genes that have been found to associate with the expression of the orofacial cleft phenotype remain to be determined.
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Affiliation(s)
- Jyotsna Murthy
- Department of Plastic Surgery, Sri Ramachandra Medical College, Chennai, India
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24
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Abstract
Orofacial clefts are common and burdensome birth defects with a complex genetic and environmental etiology. The contribution of nutritional factors and supplements to the etiology of orofacial clefts has long been theorized and studied. Multiple studies have evaluated the role of folic acid in the occurrence and recurrence of orofacial clefts, using observational and non-randomized interventional designs. While preventive effects of folic acid on orofacial clefts are commonly reported, the evidence remains generally inconsistent. This paper reviews the findings of the main studies of the effects of folic acid on orofacial clefts, summarizes study limitations, and discusses research needs with a focus on studying the effects of high dosage folic acid on the recurrence of oral clefts using a randomized clinical trial design. The role of folic acid in the prevention of neural tube defects is also briefly summarized and discussed as a reference model for orofacial clefts.
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Affiliation(s)
- G L Wehby
- Department of Health Management and Policy, College of Public Health, University of Iowa, Iowa City, IA 52242, USA
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25
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Ali A, Singh SK, Raman R. MTHFR 677TT Alone and IRF6 820GG Together with MTHFR 677CT, but Not MTHFR A1298C, Are Risks for Nonsyndromic Cleft Lip with or without Cleft Palate in an Indian Population. Genet Test Mol Biomarkers 2009; 13:355-60. [DOI: 10.1089/gtmb.2008.0115] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Akhtar Ali
- Centre for Genetic Disorders, Banaras Hindu University, Varanasi, India
| | - Subodh Kumar Singh
- G.S. Memorial Plastic Surgery Hospital and Trauma Centre, Varanasi, India
| | - Rajiva Raman
- Centre for Genetic Disorders, Banaras Hindu University, Varanasi, India
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India
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26
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Park BY, Sull JW, Park JY, Jee SH, Beaty TH. Differential parental transmission of markers in BCL3 among Korean cleft case-parent trios. J Prev Med Public Health 2009; 42:1-4. [PMID: 19229118 DOI: 10.3961/jpmph.2009.42.1.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
OBJECTIVES Isolated cleft lip with or without cleft palate (CL/P) is among the most common human birth defects, with a prevalence of approximately 1 in 700 live births. The B-Cell Leukemia/lymphoma 3 (BCL3) gene has been suggested as a candidate gene for CL/P based on association and linkage studies in some populations. This study tests for an association between markers in BCL3 and isolated, non-syndromic CL/P using a case-parent trio design, while considering parent-of-origin effects. METHODS Forty case-parent trios were genotyped for two single nucleotide polymorphisms (SNPs) in the BCL3 gene. We performed a transmission disequilibrium test (TDT) on individual SNPs, and the FAMHAP package was used to estimate haplotype frequencies and to test for excess transmission of multi-SNP haplotypes. RESULTS The odds ratio for transmission of the minor allele, OR (transmission), was significant for SNP rs8100239 (OR=3.50, p=0.004) and rs2965169 (OR=2.08, p=0.027) when parent-of-origin was not considered. Parent-specific TDT revealed that SNP rs8100239 showed excess maternal transmission. Analysis of haplotypes of rs2965169 and rs8100239 also suggested excess maternal transmission. CONCLUSIONS BCL3 appears to influence risk of CL/P through a parent-of-origin effect with excess maternal transmission.
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27
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Little J, Gilmour M, Mossey PA, FitzPatrick D, Cardy A, Clayton-Smith J, Hill A, Duthie SJ, Fryer AE, Molloy AM, Scott JM. Folate and Clefts of the Lip and Palate—A U.K.-Based Case-Control Study: Part II: Biochemical and Genetic Analysis. Cleft Palate Craniofac J 2008; 45:428-38. [DOI: 10.1597/06-151.1] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Objective: To investigate associations between nonsyndromic oral clefts and biochemical measures of folate status and the MTHFR C677T variant in the United Kingdom, where there has been no folic acid fortification program. Method: Dietary details were obtained from the mothers of 112 cases of cleft lip with or without cleft palate (CL±P), 78 cleft palate only (CP) cases, and 248 unaffected infants. Infant and parental MTHFR C677T genotype was determined. Red blood cell (RBC) and serum folate and homocysteine levels were assessed in 12-month postpartum blood samples from a subset of mothers. The data were analyzed by logistic and log-linear regression methods. Results: There was an inverse association between CL±P and maternal MTHFR CT (odds ratio [OR] = 0.5, 95% confidence interval [CI] = 0.31–0.95) and TT (OR = 0.6, 95% CI = 0.21–1.50) genotypes, with similar risk estimates for CP. There was no clear association with infant MTHFR genotype. Higher levels of maternal postpartum RBC and serum folate were associated with a lower risk for CL±P and an increased risk for CP. Higher levels of serum homocysteine were associated with a slightly increased risk for both CL±P and CP. Conclusion: While the inverse relation between the mother's having the MTHFR C677T variant and both CL±P and CP suggests perturbation of maternal folate metabolism is of etiological importance, contrasting relations between maternal postpartum levels of RBC and serum folate by type of cleft are difficult to explain.
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Affiliation(s)
- J. Little
- Human Genome Epidemiology, University of Ottawa (Canada) (formerly Professor of Epidemiology, University of Aberdeen, Scotland)
| | - M. Gilmour
- Tayside Centre for General Practice, University of Dundee, Scotland
| | - P. A. Mossey
- Craniofacial Development, University of Dundee, Scotland
| | - D. FitzPatrick
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, Scotland
| | - A. Cardy
- Primary Care, University of Aberdeen, Scotland
| | - J. Clayton-Smith
- Medical Genetics, St. Mary's Hospital for Women and Children, Manchester, England
| | - A. Hill
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, Scotland
| | - S. J. Duthie
- Rowett Research Institute, Aberdeen, Scotland, funded by the Scottish Executive Environmental and Rural Affairs Department
| | - A. E. Fryer
- Medical Genetics, Liverpool Women's Hospital, Liverpool, England
| | - A. M. Molloy
- Department of Clinical Medicine, Trinity College, Dublin 2, Ireland
| | - J. M. Scott
- Department of Biochemistry, Trinity College, Dublin 2, Ireland
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28
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Johnson CY, Little J. Folate intake, markers of folate status and oral clefts: is the evidence converging? Int J Epidemiol 2008; 37:1041-58. [PMID: 18583393 DOI: 10.1093/ije/dyn098] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The ability of folic acid in the periconceptional period to prevent the occurrence of neural tube defects has stimulated tremendous interest in its effects on other health outcomes. Its possible effect on oral clefts has generated considerable debate. The purpose of this systematic review and meta-analysis was to assemble evidence on the role of folate in the aetiology of cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). METHODS Medline, PubMed, Embase, Science Citation Index and the HuGE Published Literature Database were searched to February 2007 for articles related to oral clefts and multivitamin use, dietary folate, folic acid fortification, biochemical markers of folate status and polymorphisms in 5,10-methylenetetrahydrofolate reductase (MTHFR) and other genes involved in folate metabolism. Random effects meta-analysis was conducted when appropriate. RESULTS Maternal multivitamin use was inversely associated with CL/P [odds ratio (OR) 0.75, 95% CI 0.65-0.88, based on 5717 cases and 59 784 controls] but to a lesser extent CPO (OR 0.88, 95% CI 0.76-1.01, 2586 cases and 59 684 controls). The volume of evidence on dietary folate, fortification and biochemical and genetic measures of folate status is substantially less; in aggregate, the evidence suggests that no association exists but there is substantial heterogeneity between studies. CONCLUSIONS The evidence is not converging and there is no strong evidence for an association between oral clefts and folic acid intake alone. Multivitamin use in early pregnancy, however, may protect against oral clefts, especially CL/P although this association may be confounded by other lifestyle factors associated with multivitamin use.
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Affiliation(s)
- Candice Y Johnson
- Department of Epidemiology and Community Medicine, University of Ottawa, Ottawa, Canada
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29
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Abstract
The focus of this work is to highlight the most recent advances in the understanding of cleft lip and palate occurrence. Information regarding research on long-term outcomes, genes and their interactions with other genes, and gene-environment interactions is compiled to provide the reader with a critical and up-to-date overview on the current knowledge of the etiology of cleft lip and palate. Recent epidemiological evidence strongly suggests that individuals born with clefts have a shorter lifespan and may have a higher incidence of cancer and psychological disorders. IRF6 has been shown to be an important contributor to cleft lip and palate, but the functional variant leading to the defect has not yet been defined. Inactivation of MSX1 and genes in the FGF family has also been shown to lead to cleft lip and palate. In addition, missense mutations in several candidate genes may cause cleft lip and palate, but definitive evidence regarding the biological consequences of these mutations is yet to be unraveled. Maternal cigarette smoking increases the risk of a baby born with clefts, in particular when the mother carries the GSTT1-null variants. The latest approaches in cleft research include the analysis of several additional phenotypical features of the population, with the goal of increasing the statistical power of genetics studies.
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Affiliation(s)
- A R Vieira
- Departments of Oral Biology and Pediatric Dentistry, School of Dental Medicine, University of Pittsburgh, PA 15261, USA.
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Boyles AL, Wilcox AJ, Taylor JA, Meyer K, Fredriksen A, Ueland PM, Drevon CA, Vollset SE, Lie RT. Folate and one-carbon metabolism gene polymorphisms and their associations with oral facial clefts. Am J Med Genet A 2008; 146A:440-9. [PMID: 18203168 DOI: 10.1002/ajmg.a.32162] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Folate metabolism plays a critical role in embryonic development. Prenatal folate supplementation reduces the risk of neural tube defects and probably oral facial clefts. Previous studies of related metabolic genes have associated polymorphisms in cystathionine-beta-synthase (CBS) and 5,10-methylenetetrahydrofolate reductase (MTHFR) with cleft risk. We explored associations between genes related to one-carbon metabolism and clefts in a Norwegian population-based study that included 362 families with cleft lip with or without cleft palate (CL/P) and 191 families with cleft palate only (CPO). We previously showed a 39% reduction in risk of CL/P with folic acid supplementation in this population. In the present study we genotyped 12 polymorphisms in nine genes related to one-carbon metabolism and looked for associations of clefting risk with fetal polymorphisms, maternal polymorphisms, as well as parent-of-origin effects, using combined likelihood-ratio tests (LRT). We also stratified by maternal periconceptional intake of folic acid (>400 microg) to explore gene-exposure interactions. We found a reduced risk of CL/P with mothers who carried the CBS C699T variant (rs234706); relative risk was 0.94 with one copy of the T allele (95% CI 0.63-1.4) and 0.50 (95% CI 0.26-0.96) with two copies (P = 0.008). We found no evidence of interaction of this variant with folate status. We saw no evidence of risk from the MTHFR C677T variant (rs1801133) either overall or after stratifying by maternal folate intake. No associations were found between any of the polymorphisms and CPO. Genetic variations in the nine metabolic genes examined here do not confer a substantial degree of risk for clefts.
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Affiliation(s)
- Abee L Boyles
- Epidemiology Branch, National Institute of Environmental Health Sciences/NIH, Durham, North Carolina 27709, USA.
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Methylenetetrahydrofolate reductase C677T and A1298C polymorphisms and susceptibility to gastric adenocarcinoma in an Italian population. PLoS One 2007; 9:e88242. [PMID: 24658649 PMCID: PMC3962346 DOI: 10.1371/journal.pone.0088242] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 01/09/2014] [Indexed: 01/16/2023] Open
Abstract
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.
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Carinci F, Scapoli L, Palmieri A, Zollino I, Pezzetti F. Human genetic factors in nonsyndromic cleft lip and palate: an update. Int J Pediatr Otorhinolaryngol 2007; 71:1509-19. [PMID: 17606301 DOI: 10.1016/j.ijporl.2007.06.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 05/30/2007] [Accepted: 06/02/2007] [Indexed: 10/23/2022]
Abstract
Nonsyndromic cleft lip and/or palate (or orofacial cleft, OFC) is a malformation characterized by an incomplete separation between nasal and oral cavities without any associated anomalies. The last point defines the distinction between syndromic and nonsyndromic OFC. Nonsyndromic OFC is one of the most common malformations among live births and is composed of two separate entities: cleft lip with or without cleft palate (CL+/-P) and cleft palate isolated (CPI). Because of the complex etiology of nonsyndromic OFC, which is due to the differences between CL+/-P and CPI, and the heterogeneity of each group, caused by the number of genes involved, the type of inheritance, and the interaction with environmental factors, we reviewed those genes and available loci in the literature whose involvement in the onset of nonsyndromic OFC has more sound scientific evidence. Genetic studies on human populations have demonstrated that CL+/-P and CPI have distinct genetic backgrounds and, therefore, environmental factors probably disclose only these malformations. In CL+/-P several loci, OFC from 1 to 10 have been identified. The first locus, OFC1, has been mapped to chromosome 6p24. Other CL+/-P loci have been mapped to 2p13 (OFC2), 19q13.2 (OFC3) and 4q (OFC4). OFC5-8 are identified by mutations in the MSX1, IRF6, PVRL1, and TP73L gene, respectively. OFC9 maps to 13q33.1-q34, whereas OFC10 is associated with haploinsufficiency of the SUMO1 gene. In addition, MTHFR, TGF-beta3, and RARalpha play a role in cleft onset. In CPI one gene has been identified (TBX22) at present, but others are probably involved. Greater efforts are necessary in order to have a complete picture of the main factors involved in lip and palate formation. These elements will permit us to better understand and better treat patients affected by OFC.
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MESH Headings
- Chromosomes, Human, Pair 13/genetics
- Chromosomes, Human, Pair 19/genetics
- Chromosomes, Human, Pair 2/genetics
- Chromosomes, Human, Pair 6/genetics
- Chromosomes, Human, Pair 8/genetics
- Cleft Lip/genetics
- Cleft Palate/genetics
- Gene Expression/genetics
- Humans
- Polymorphism, Restriction Fragment Length/genetics
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Affiliation(s)
- Francesco Carinci
- Department of D.M.C.C.C., Section of Maxillofacial Surgery, University of Ferrara, Corso, Giovecca 203, 44100 Ferrara, Italy.
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Verkleij-Hagoort A, Bliek J, Sayed-Tabatabaei F, Ursem N, Steegers E, Steegers-Theunissen R. Hyperhomocysteinemia and MTHFR polymorphisms in association with orofacial clefts and congenital heart defects: a meta-analysis. Am J Med Genet A 2007; 143A:952-60. [PMID: 17431894 DOI: 10.1002/ajmg.a.31684] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Several studies have reported an association between hyperhomocysteinemia, 5,10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and cleft lip with or without cleft palate (CLP), and congenital heart defects (CHDs). However, findings have been inconsistent. A meta-analysis was performed of published studies until September 2006 investigating these associations in both mothers and children. Homocysteine data were provided in two CLP and three CHD studies, and MTHFR polymorphisms were reported in ten CLP and eight CHD studies. Data were analyzed using the random effects model in the Cochrane Review Manager. The pooled odds ratio (OR) of maternal hyperhomocysteinemia was 2.3 (95% CI 0.4-11.9) for CLP, and 4.4 (2.6-7.3) for CHDs. The MTHFR C677T polymorphism and CLP showed pooled ORs of 1.2 (0.9-1.5) in mothers and 1.0 (0.9-1.2) in children, whereas these estimates for the A1298C polymorphism were 1.0 (0.7-1.2) in mothers and 0.9 (0.6-1.2) in children. The MTHFR C677T polymorphism in CHD studies demonstrated a pooled OR of 1.0 (0.8-1.3) for mothers and 1.1 (0.9-1.5) for children. Two studies investigating the maternal A1298C polymorphism in CHDs demonstrated a pooled OR of 1.2 (0.8-1.8). Only one CHD study reported an OR of 1.3 (0.8-2.1) for this polymorphism in children. In conclusion, this meta-analysis demonstrates that maternal hyperhomocysteinemia is a risk factor for CHDs. The MTHFR polymorphisms C677T and A1298C in both mothers and children are not independently associated with CLP or CHDs. Future studies should be performed to investigate the interactions between maternal hyperhomocysteinemia, B-vitamin intake, related polymorphisms and the risk of CLP and CHDs.
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Affiliation(s)
- Anna Verkleij-Hagoort
- Department of Obstetrics and Gynecology/Division of Obstetrics and Prenatal Medicine, Erasmus MC, University Medical Center, Rotterdam, The Netherlands
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Errera FIV, Silva MER, Yeh E, Maranduba CMC, Folco B, Takahashi W, Pereira AC, Krieger JE, Passos-Bueno MR. Effect of polymorphisms of the MTHFR and APOE genes on susceptibility to diabetes and severity of diabetic retinopathy in Brazilian patients. Braz J Med Biol Res 2006; 39:883-8. [PMID: 16862278 DOI: 10.1590/s0100-879x2006000700005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 03/27/2006] [Indexed: 02/07/2023] Open
Abstract
Diabetes mellitus (DM) is a highly prevalent complex genetic disorder. There has been a worldwide effort in the identification of susceptibility genes for DM and its complications, and the 5-10-methylenetetrahydrofolate reductase (MTHFR) and apolipoprotein-E (APOE) genes have been considered good candidate susceptibility genes to this condition. The objectives of the present study were to determine if the 677T MTHFR and epsilon2/epsilon3/epsilon4 APOE alleles are risk factors for DM and for severity of diabetic retinopathy (DR). A total of 248 individuals were studied: 107 healthy individuals and 141 diabetic patients (46 with type 1 diabetes and 95 with type 2 diabetes), who also had DR (81 with non-proliferative DR and 60 with proliferative DR). The polymorphisms were analyzed by PCR followed by digestion with restriction enzyme or the single-nucleotide primer extension method. No evidence of association between the 677TT genotype of MTHFR gene and DM [cases: TT = 10/95 (10.6%); controls: TT = 14/107 (13%)] or with severity of DR was observed [cases: TT = 5/60 (8.5%); controls: TT = 9/81 (11.1%); P > 0.05]. We also did not find evidence of an association between APOE alleles and proliferative DR (epsilon2, epsilon3 and epsilon4 in cases: 9, 76, and 15%, and in controls: 5, 88, and 12%, respectively) but the carriers of epsilon2 allele were more frequent among patients with type 2 DM and DR than in controls [cases: 15/95 (15.8%); controls: 7/107 (6.5%); P < 0.05]. Therefore, our results suggest that the epsilon2 allele/APOE might be a risk factor for diabetes in the Brazilian population.
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Affiliation(s)
- F I V Errera
- Centro de Estudos do Genoma Humano, Instituto de Biociências, USP, São Paulo, SP, Brasil
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Abstract
Mutations in the p63 gene (TP63) underlie several monogenic malformation syndromes manifesting cleft lip with or without cleft palate (CL/P). We investigated whether p63 mutations also result in non-syndromic CL/P. Specifically, we performed mutation analysis of the 16 exons of the p63 gene for 100 Thai patients with non-syndromic CL/P. In total, 21 variant sites were identified. All were single nucleotide changes, with six in coding regions, including three novel non-synonymous changes: S90L, R313G, and D564H. The R313G was concluded to be pathogenic on the basis of its amino acid change, evolutionary conservation, its occurrence in a functionally important domain, its predicted damaging function, its de novo occurrence, and its absence in 500 control individuals. Our data strongly suggest, for the first time, a causative role of a heterozygous mutation in the p63 gene in non-syndromic CL/P, highlighting the wide phenotypic spectrum of p63 gene mutations.
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Krapels IP, Vermeij-Keers C, Müller M, de Klein A, Steegers-Theunissen RP. Nutrition and Genes in the Development of Orofacial Clefting. Nutr Rev 2006; 64:280-8. [PMID: 16808114 DOI: 10.1111/j.1753-4887.2006.tb00211.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Clefts of the lip, alveolus, and/or palate, which are called orofacial clefts (OFC), occur in 0.5 to 3 per 1000 live and stillbirths. The pathogenesis of these congenital malformations remains largely unknown, but evidence is increasing that both nutritional and genetic factors are involved. Unlike genetic factors, nutritional causes can be corrected and may therefore contribute to the prevention of OFC. The goal of this review is to summarize the embryogenesis and genes involved in OFC, and to give an overview of the nutrients and related genes in humans. Improving our knowledge of the role of nutrition, genes, and their interactions in the pathogenesis of OFC may stimulate the development of nutritional interventions for OFC prevention in the future.
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Affiliation(s)
- Ingrid P Krapels
- Department of Epidemiology, Radboud University Nijmegen Medical Center, the Netherlands
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Vieira AR. Association between the transforming growth factor alpha gene and nonsyndromic oral clefts: a HuGE review. Am J Epidemiol 2006; 163:790-810. [PMID: 16495466 DOI: 10.1093/aje/kwj103] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transforming growth factor alpha (TGFA) is a well-characterized mammalian growth factor. Since the first report of an association between DNA sequence variants at the TGFA genetic locus and nonsyndromic oral clefts, 47 studies have been carried out, producing conflicting results. In this review, the author synthesizes findings from published reports on the association between the TGFA gene and clefting in humans. Bias, lack of statistical power, and genuine population diversity can explain the diverse results. In the aggregate, TGFA is probably a genetic modifier of clefting in humans, which is consistent with the oligogenic model suggested for nonsyndromic oral clefts.
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Affiliation(s)
- Alexandre R Vieira
- Department of Oral Medicine and Pathology, School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA.
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Abstract
PURPOSE OF REVIEW Orofacial clefts are common birth defects with a known genetic component to their etiology. Most orofacial clefts are nonsyndromic, isolated defects, which can be separated into two different phenotypes: (1) cleft lip with or without cleft palate and (2) cleft palate only. Both are genetically complex traits, which has limited the ability to identify disease loci or genes. The purpose of this review is to summarize recent progress of human genetic studies in identifying causal genes for isolated or nonsyndromic cleft lip with or without cleft palate. RECENT FINDINGS The results of multiple genome scans and a subsequent meta-analysis have significantly advanced our knowledge by revealing novel loci. Furthermore, candidate gene approaches have identified important roles for IRF6 and MSX1. To date, causal mutations with a known functional effect have not yet been described. SUMMARY With the implementation of genome-wide association studies and inexpensive sequencing, future studies will identify disease genes and characterize both gene-environment and gene-gene interactions to provide knowledge for risk counseling and the development of preventive therapies.
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Affiliation(s)
- Andrew C Lidral
- Department of Orthodontics, University of Iowa, Iowa City, Iowa 52242, USA.
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