Maternal biomarkers of methylation status and non-syndromic orofacial cleft risk: a meta-analysis

Maternal micronutrient biomarkers and risk of non-syndromic cleft lip/palate: A case-control study

OBJECTIVE

This case-control study investigated the associations between maternal plasma vitamin B12, homocysteine, and red blood cell (RBC) folate levels and the risk of cleft lip with or without cleft palate (CL/P) in offspring.

SUBJECTS AND METHODS

The study compared 94 mothers and children with non-syndromic CL/P from a teaching hospital in Thailand to 94 mother-infant controls from local well-baby clinics, frequency-matched by birth date and mother's education. Data included anthropometric measurements, blood sample analyses, and a questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) estimated the associations through multiple logistic regression, adjusting for confounders.

RESULTS

Mothers with higher plasma vitamin B12 levels had a lower risk of having a child with CL/P compared to those in the lowest quartile. This association was more pronounced among mothers without a family history of orofacial clefts and those who were not underweight. Conversely, elevated homocysteine levels, a marker of impaired B vitamin metabolism, increased the risk of CL/P. No association was found between RBC folate and CL/P.

CONCLUSION

Higher maternal vitamin B12 levels are associated with a reduced risk of CL/P, while elevated homocysteine levels may increase the risk.

PEMT variants are associated with nonsyndromic cleft lip with or without cleft palate in Chile

Aim: To assess the association between PEMT variants and nonsyndromic cleft lip with or without cleft palate in Chile and the effects of these variants on global DNA methylation. Subjects & methods: The authors obtained genotypes for nine variants from 247 cases and 453 controls for genotype-phenotype associations. The effect of significant polymorphisms on global DNA methylation (percentage of long interspersed element-1 methylation) was evaluated in a subsample of 95 controls. Results: After multiple comparison corrections, variants rs7649 and rs4646409 were associated with nonsyndromic cleft lip with or without cleft palate. Carriers of risk alleles presented lower DNA methylation levels than noncarriers. Conclusion: According to functional analysis for risk variants from previous reports, the authors infer that a decrease of methyl group availability is occurring in affected subjects.

Association and Interaction Effect of BHMT Gene Polymorphisms and Maternal Dietary Habits with Ventricular Septal Defect in Offspring

This study attempted to learn the association between maternal betaine-homocysteine methyltransferase (BHMT) gene polymorphisms, maternal dietary habits, and their interactions with the risk of ventricular septal defects (VSD) in offspring. A total of 426 mothers of VSD children and 740 control mothers were included in the study. Logistic regression was used to evaluate the level of associations and interaction effects. Our study suggested that mothers reporting excessive intake of smoked foods (aOR = 2.44, 95%CI: 1.89–3.13), barbecued foods (aOR = 1.86, 95%CI: 1.39–2.48), fried foods (aOR = 1.93, 95%CI: 1.51–2.46), and pickled vegetables (aOR = 2.50, 95%CI: 1.92–3.25) were at a significantly higher risk of VSD in offspring, instead, mothers reporting regular intake of fresh fruits (aOR = 0.47, 95%CI: 0.36–0.62), fish and shrimp (aOR = 0.35, 95%CI: 0.28–0.44), fresh eggs, (aOR = 0.56, 95%CI: 0.45–0.71), beans (aOR = 0.68, 95%CI: 0.56–0.83), and milk products (aOR = 0.67, 95%CI: 0.56–0.80) were at a lower risk of VSD in offspring. In addition, maternal BHMT gene polymorphisms at rs1316753 (CG vs. CC: aOR = 2.01, 95%CI: 1.43–2.83) and rs1915706 (CT vs. TT: (aOR = 1.81, 95%CI: 1.33–2.46) were significantly associated with increased risk of VSD in offspring. Furthermore, a significant interaction between BHMT polymorphisms and maternal bean intake was identified in the study. In conclusion, Maternal BHMT polymorphisms at rs1316753 and rs1915706, dietary habits as well as their interaction were observed to be significantly associated with the risk of VSD in offspring.

Environmental factors in non-syndromic orofacial clefts: A review based on meta-analyses results

Non-syndromic orofacial clefts (NSOFCs) are prevalent birth defects with a complex etiology where several interacting genetic and environmental factors have been observed. This narrative review describes maternal exposures that have been significantly associated with protective effects or risk factors. The statistically significant information reported here was found in meta-analysis studies, taking advantage of their precision in defining intervention effects and their management of heterogeneity between studies. In addition, I propose a hypothesis explaining the biological basis for the results of the meta-analyses. This review aims to improve the evidence available in parent counseling, to prevent the occurrence of orofacial clefts by suggesting lifestyle changes.

Maternal genotypes of folate/one-carbon metabolism gene variants and nonsyndromic cleft lip with or without cleft palate risk in Chile

The aim of this study was to evaluate, in a case-control design, the association between maternal genotypes for variants in 23 genes involved in folate/one-carbon metabolism and nonsyndromic cleft lip with or without cleft palate (NSCL/P) in a Chilean population. After applying several filters to an Illumina array, we extracted 175 single nucleotide polymorphisms (SNPs) from 150 mothers of NSCL/P cases and 150 control women. Association was evaluated using computed odds ratio (OR) with a 95% confidence interval (95% CI) in additive, recessive, and dominant models. After multiple comparison correction, only SNP rs4451422 (A>C), located 237 bp downstream of the gene encoding the human folylpolyglutamate synthetase (FPGS), maintained a significant association with NSCL/P in the offspring (OR 3.03; 95% CI 1.69-5.26). The variant rs4451422 is associated with a decrease in FPGS expression according to database annotation. Our results lead to a new hypothesis that a lower activity of FPGS enzyme reduces intracellular folate levels and increases the risk of an offspring having NSCL/P.

Maternal Vitamin B12 Status and Risk of Cleft Lip and Cleft Palate Birth Defects in Tamil Nadu State, India

BACKGROUND AND OBJECTIVE

The causal role of maternal nutrition in orofacial clefts is uncertain. We tested hypotheses that low maternal vitamin B₁₂ and low folate status are each associated with an increased risk of isolated cleft lip with or without cleft palate (CL±P) in a case-control study in Tamil Nadu state, India.

METHODS

Case-mothers of CL±P children (n = 47) and control-mothers of unaffected children (n = 50) were recruited an average of 1.4 years after birth of the index child and plasma vitamin B₁₂, methylmalonic acid (MMA), total homocysteine (tHcy), and folate were measured at that time. Logistic regression analyses estimated associations between nutrient biomarkers and case-control status.

RESULTS

Odds ratios (ORs) contrasting biomarker levels showed associations between case-mothers and low versus high plasma vitamin B₁₂ (OR = 2.48, 95% CI, 1.02-6.01) and high versus low plasma MMA, an indicator of poor B₁₂ status (OR = 3.65 95% CI, 1.21-11.05). Case-control status was not consistently associated with folate or tHcy levels. Low vitamin B₁₂ status, when defined by a combination of both plasma vitamin B₁₂ and MMA levels, had an even stronger association with case-mothers (OR = 6.54, 95% CI, 1.33-32.09).

CONCLUSIONS

Mothers of CL±P children in southern India were 6.5 times more likely to have poor vitamin B₁₂ status, defined by multiple biomarkers, compared to control-mothers. Further studies in populations with diverse nutritional backgrounds are required to determine whether poor maternal vitamin B₁₂ or folate levels or their interactions are causally related to CL±P.

Orofacial clefts embryology, classification, epidemiology, and genetics

Orofacial clefts (OFCs) rank as the second most common congenital birth defect in the United States after Down syndrome and are the most common head and neck congenital malformations. They are classified as cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). OFCs have significant psychological and socio-economic impact on patients and their families and require a multidisciplinary approach for management and counseling. A complex interaction between genetic and environmental factors contributes to the incidence and clinical presentation of OFCs. In this comprehensive review, the embryology, classification, epidemiology and etiology of clefts are thoroughly discussed and a "state-of-the-art" snapshot of the recent advances in the genetics of OFCs is presented.

Effect of folic acid on animal models, cell cultures, and human oral clefts: a literature review

Background

Folate is a naturally occurring, water-soluble B vitamin. The synthetic form of this compound is folic acid (FA), the deficiency of which is linked to neural tube disorders (NTD), which can be prevented by consuming it before, or during the early months of, pregnancy. However, the effect of FA on oral cleft formation remains controversial. The aim of the present study was to review the evidence concerning the effect of FA on the formation of cleft lip and palate (CLP) in both animals and humans, as well as its impact on different cell types. A search was conducted on various databases, including MEDLINE, EMBASE, and Central, for articles published until January 2020.

Main body

Current systematic reviews indicate that FA, alone or in combination with other vitamins, prevents NTD; however, there is no consensus on whether its consumption can prevent CLP formation. Conversely, the protective effect of FA on palatal cleft (CP) induction has been inferred from animal models; additionally, in vitro studies enumerate a cell-type and dose-dependent effect of FA on cell viability, proliferation, and differentiation, hence bolstering evidence from epidemiological studies.

Conclusions

Meta-analysis, animal models, and in vitro studies demonstrated the protective effect of FA against isolated CP; however, the heterogeneity of treatment protocols, doses, and FA administration method, as well as the different cell types used in in vitro studies, does not conclusively establish whether FA prevents CLP formation.

Folate intake, markers of folate status and oral clefts: An updated set of systematic reviews and meta-analyses

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.

Maternal intake of caffeinated products and birth defects: a systematic review and meta-analysis of observational studies

Caffeinated products are frequently consumed by women of childbearing age worldwide. It still unclear that whether maternal intake of caffeine associated with an increased risk of birth defects. We searched the databases of PubMed, Embase, the Cochrane Library, and Web of Science for eligible studies through July 2020. All studies examining the association between maternal consumption of caffeine or caffeinated products and birth defects were included. Twenty-nine studies were included in this meta-analysis. Among all the birth defects, maternal caffeine consumption was associated with a higher risk of cardiovascular defects, [odds ratio (OR) 1.17; 95% confidence interval (CI), 1.07-1.28], craniofacial defects (OR 1.09; 95% CI, 1.02-1.17), alimentary tract defects (OR 1.35; 95% CI, 1.16-1.56), and abdominal-wall defects and hernia (OR 1.13; 95% CI, 1.03-1.25). No association was found between maternal caffeine intake and musculoskeletal system defects, genitourinary system defects, nervous system defects, or chromosomal abnormalities. Meanwhile, all three of the caffeine consumption categories (low, moderate, and high) were associated with a higher risk of cardiovascular defects and alimentary tract defects.

Nucleic acid methylation and orofacial morphogenesis

In this review, we highlight the current state of knowledge of the diverse roles nucleic acid methylation plays in the embryonic development of the orofacial region and how aberrant methylation may contribute to orofacial clefts. We also consider the role of methylation in the regulation of neural crest cell function as it pertains to orofacial ontogeny. Changes in DNA methylation, as a consequence of environmental effects, have been observed in the regulatory regions of several genes, potentially identifying new candidate genes for orofacial clefting and opening promising new avenues for further research. While the focus of this review is primarily on the nonsyndromic forms of orofacial clefting, syndromic forms are briefly discussed in the context of aberrant nucleic acid methylation.

Methyl Donor Micronutrients that Modify DNA Methylation and Cancer Outcome

DNA methylation is an epigenetic mechanism that is essential for regulating gene transcription. However, aberrant DNA methylation, which is a nearly universal finding in cancer, can result in disturbed gene expression. DNA methylation is modified by environmental factors such as diet that may modify cancer risk and tumor behavior. Abnormal DNA methylation has been observed in several cancers such as colon, stomach, cervical, prostate, and breast cancers. These alterations in DNA methylation may play a critical role in cancer development and progression. Dietary nutrient intake and bioactive food components are essential environmental factors that may influence DNA methylation either by directly inhibiting enzymes that catalyze DNA methylation or by changing the availability of substrates required for those enzymatic reactions such as the availability and utilization of methyl groups. In this review, we focused on nutrients that act as methyl donors or methylation co-factors and presented intriguing evidence for the role of these bioactive food components in altering DNA methylation patterns in cancer. Such a role is likely to have a mechanistic impact on the process of carcinogenesis and offer possible therapeutic potentials.

Periconceptional maternal one-carbon biomarkers are associated with embryonic development according to the Carnegie stages

STUDY QUESTION

Is periconceptional maternal one-carbon (I-C) metabolism associated with embryonic morphological development in non-malformed ongoing pregnancies?

SUMMARY ANSWER

Serum vitamin B12, red blood cell (RBC) folate and plasma total homocysteine (tHcy) are associated with embryonic development according to the Carnegie stages.

WHAT IS KNOWN ALREADY

Derangements in maternal I-C metabolism affect reproductive and pregnancy outcomes, as well as future health of the offspring.

STUDY DESIGN, SIZE, DURATION

Between 2010 and 2014, women with singleton ongoing pregnancies were enrolled in a prospective periconceptional cohort study.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 234 pregnancies, including 138 spontaneous or IUI pregnancies with strict pregnancy dating and 96 pregnancies derived from IVF, ICSI or cryopreserved embryo transfer (IVF/ICSI pregnancies), underwent longitudinal transvaginal three-dimensional ultrasound (3D US) scans from 6+0 up to 10+2 weeks of gestation. Carnegie stages were defined using internal and external morphologic criteria in a virtual reality system. Maternal venous blood samples were collected at enrollment for serum vitamin B12, RBC folate and plasma tHcy assessment. Associations between biomarker concentrations and longitudinal Carnegie stages were investigated using linear mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

We performed a median of three 3D US scans per pregnancy (range 1-5) resulting in 600 good quality data sets for the Carnegie stage annotation (80.5%). Vitamin B12 was positively associated with embryonic development in the total study population (β = 0.001 (95% CI: 0.000; 0.002), P < 0.05) and in the subgroup of strictly dated spontaneous pregnancies (β = 0.002 (95% CI: 0.001; 0.003), P < 0.05). Low vitamin B12 concentrations (-2SD, 73.4 pmol/l) were associated with delayed embryonic development by 1.4 days (95% CI: 1.3-1.4) compared with high concentrations (+2SD, 563.1 pmol/l). RBC folate was positively associated with Carnegie stages only in IVF/ICSI pregnancies (β = 0.001 (95% CI: 0.0005; 0.0015), P < 0.05). In this group, low RBC folate concentrations (-2SD, 875.4 nmol/l) were associated with a 1.8-day delay (95% CI: 1.7-1.8) in development compared with high concentrations (+2SD, 2119.9 nmol/l). tHcy was negatively associated with embryonic development in the total study population (β = -0.08 (95% CI: -0.14; -0.02), P < 0.01), as well as in the IVF/ICSI subgroup (β = -0.08 (95% CI: -0.15; -0.01), P < 0.05). High tHcy concentrations (+2SD, 10.4 µmol/l) were associated with a delay of 1.6 days (95% CI: 1.5-1.7) in embryonic development compared with low concentrations (-2SD, 3.0 µmol/l).

LIMITATIONS, REASONS FOR CAUTION

The study was performed in a tertiary care center, resulting in high rates of folic acid supplement use and comorbidity that may reduce the external validity of our findings.

WIDER IMPLICATIONS OF THE FINDINGS

In periconceptional care, maternal I-C biomarkers should be taken into account as predictors of embryonic morphological development. Combining embryonic size measurements with morphological assessment could better define normal embryonic development.

STUDY FUNDING/COMPETING INTEREST(S)

The work was funded by the Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Centre, Rotterdam, The Netherlands. RPMST is CSO of the startup company Slimmere Zorg and CEO of eHealth Care Solutions. The authors declare no conflicts of interest.

TRIAL REGISTRATION NUMBER

Not applicable.

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.