Cause Of Neural Tube Defects Research Articles

Maternal Smoking during Pregnancy and its effects on Neural Tube Defects.

Maternal smoking is a potent teratogen among congenital malformations, however its role in the development of Neural Tube Defects (NTDs) is still unclear. In this systematic review, we intend to further investigate the interaction of smoking during pregnancy and the incidence of NTDs. This article was written according to PRISMA criteria from February 2015 and August 2022. After examining the four stages of PRISMA criteria, we selected clinical articles. These articles were selected from PubMed, Scopus and Google scholar (for results follow-up) databases. We gathered NTDs effect and types, smoking type and habit of parents, from neonates. Eventually, 8 articles were included by two separated authors, Smoking was associated with an increase NTDs in the population of pregnant mothers and also among children whose fathers smoked. The main side effects that were considered to be the cause of NTDs besides smoking were alcohol and BMI (18.5-24.9). Smoking also affects the level of folic acid as a substance with an essential role that affects the closure of the neural tube. folic acid available to infants changing along with the level of other blood elements such as zinc, that necessary prevent for NTDs condition. Parental smoking can be considered as one of the strong teratogens in the occurrence of NTDs. Smoking, whether active or passive by the mother, or by the father, is associated with the occurrence of NTDs, In order to reduce the prevalence this disorder, we advise pregnant mothers and neonate's fathers to quit smoking.

A Shared Pathogenic Mechanism for Valproic Acid and SHROOM3 Knockout in a Brain Organoid Model of Neural Tube Defects.

Neural tube defects (NTDs), including anencephaly and spina bifida, are common major malformations of fetal development resulting from incomplete closure of the neural tube. These conditions lead to either universal death (anencephaly) or severe lifelong complications (spina bifida). Despite hundreds of genetic mouse models of neural tube defect phenotypes, the genetics of human NTDs are poorly understood. Furthermore, pharmaceuticals, such as antiseizure medications, have been found clinically to increase the risk of NTDs when administered during pregnancy. Therefore, a model that recapitulates human neurodevelopment would be of immense benefit to understand the genetics underlying NTDs and identify teratogenic mechanisms. Using our self-organizing single rosette cortical organoid (SOSR-COs) system, we have developed a high-throughput image analysis pipeline for evaluating the SOSR-CO structure for NTD-like phenotypes. Similar to small molecule inhibition of apical constriction, the antiseizure medication valproic acid (VPA), a known cause of NTDs, increases the apical lumen size and apical cell surface area in a dose-responsive manner. GSK3β and HDAC inhibitors caused similar lumen expansion; however, RNA sequencing suggests VPA does not inhibit GSK3β at these concentrations. The knockout of SHROOM3, a well-known NTD-related gene, also caused expansion of the lumen, as well as reduced f-actin polarization. The increased lumen sizes were caused by reduced cell apical constriction, suggesting that impingement of this process is a shared mechanism for VPA treatment and SHROOM3-KO, two well-known causes of NTDs. Our system allows the rapid identification of NTD-like phenotypes for both compounds and genetic variants and should prove useful for understanding specific NTD mechanisms and predicting drug teratogenicity.

Craniorachischisis in a 33-week-old Female Fetus: A Case Report

We report the case of a 33-week-old female fetus born with craniorachischisis to a gravida 5, para 4 (3104) mother with no previous history of conceiving a child with a neural tube defect. Craniorachischisis is characterized by anencephaly and an open defect extending from the brain to the spine and is the most severe and fatal type of neural tube defect. Although the cause of neural tube defects is hypothesized to be multifactorial and is usually sporadic, the risk is increased in neonates born to mothers with a family history or a previous pregnancy with neural tube defect, both of which are not present in the index case. This case is unique in that only during the fifth pregnancy did the couple conceive a child with a neural tube defect, emphasizing that folic acid supplementation, the sole preventive measure proven to decrease the risk of neural tube defects, remains to be important in the periconceptual period for all women of childbearing age. &nbsp

Folic acid deficiency and neural tube defects: the awareness dilemma

One of the most common vitamin deficiencies among childbearing-aged women is folic acid deficiency. Folic acid deficiency is a leading cause of neural tube defects (NTDs) such as anencephaly, spina bifida, and encephalocele, which represents a major cause of serious disabilities and mortality among the infant population. Several studies showed that up to 50% of NTDs cases can be prevented by using folic acid containing supplement. Hence, planned pregnancy and awareness of mother toward this preventable method, plays a crucial role in decreasing NTDs burden. In this mini-review, we explore the prevalence and awareness of folic acid supplementation among childbearing women in different countries around the world, especially in low and middle income countries (LMICs), as well as, reveal the importance of food fortification with folic acid on NTDs burden. The overall awareness about the role of folic acid supplements in prevention of NTDs is low globally, especially in LMICs. Furthermore, compliance of folic acid supplements among childbearing-aged women during periconceptional period is also low. In summary, the findings indicate the importance of improving the awareness level of the importance of folic acid supplementation among women of childbearing age globally, especially in LMICs. It is suggested to promote the advantage of taking folic acid during the ideal time to reduce incidents of NTDs through proper education provided to women by health-care providers. Moreover, LMICs may have food fortification programs, nevertheless, the desirable effects have not achieved due to several limitations. Accordingly, improvement of these programs are required to decrease this dilemma and then to decrease NTDs burden globally, especially in LMICs.

Lessons from dolutegravir and neural tube defects

The relatively uncommon neural tube defects (NTDs) are among the most severe birth defects that affect an estimated 300 000 births annually. 1 Zaganjor I Sekkarie A Tsang BL et al. Describing the prevalence of neural tube defects worldwide: a systematic literature review. PLoS One. 2016; 11e0151586 Crossref PubMed Scopus (214) Google Scholar Although the causes of NTDs are multifactorial and difficult to study, folate supplementation is well established in their prevention. In this context, the 2018 announcement that preconception use of dolutegravir was associated with four NTDs in a population-based surveillance study in Botswana generated immediate and massive concern. 2 Zash R Shapiro R Neural-tube defects with dolutegravir treatment from the time of conception. N Engl J Med. 2018; 379: 979-981 Crossref PubMed Scopus (202) Google Scholar Dolutegravir was at that time poised to become the preferred first-line antiretroviral agent throughout international guidelines; the announcement sent shockwaves through the HIV world, as regulators, scientists, policy makers and people living with HIV sought to grapple with this possible association. 3 Laker EA Arinaitwe A Owarwo N et al. The potential teratogenicity alert for women conceiving on dolutegravir-based regimens: an assessment of risk communication by an urban HIV clinic in Uganda and choices made by women. Drug Saf. 2020; 43: 1133-1140 Crossref PubMed Scopus (3) Google Scholar

A homozygous pathogenic variant in SHROOM3 associated with anencephaly and cleft lip and palate.

Neural tube defects (NTD) are among the most common congenital anomalies, affecting about 1:1000 births. In most cases, the etiology of NTD is multifactorial and the genetic variants associated with them remain largely unknown. There is extensive evidence from animal models over the past two decades implicating SHROOM3 in neural tube formation; however, its exact role in human disease has remained elusive. In this report, we present the first case of a human fetus with a homozygous loss of function variant in SHROOM3. The fetus presents with anencephaly and cleft lip and palate, similar to previously described Shroom3 mouse mutants and is suggestive of a novel monogenic cause of NTD. Our case provides clarification on the contribution of SHROOM3 to human development after decades of model organism research.

Folic Acid Supplementation can Reduce the Risk of Neural Tube Defects in Fetus

Neural tube defects are among the abnormalities in the fetus that most often occur after heart defects and abnormalities in the genitourinary system. The causes of neural tube accidents are generally multifactorial. One of the causes of neural tube defects is a folic acid deficiency. Folic acid is essential for embryological development during pregnancy. Most cases of folic acid deficiency often go undiagnosed. Many pregnant women do not realize that they have a folic acid deficiency. The purpose of this paper is to examine the effect of folic acid supplementation on reducing the risk of neural tube defects in the fetus. This study uses the literature review method with searches sourced from the NCBI database, the researcher only captures articles published in the period between 2010 - 2020. Of all the articles obtained, 25 selected articles were analyzed using the systematic literature review method by comparing it from the title, approach, objectives, results, and discussion, then analyzed and arranged systematically. From several sources that have been found, it is stated that folic acid supplementation can reduce the risk of neural tubes in the fetus.

Role of Congenital Cytomegalovirus Infection and Protein 53 in Neural tube Defect

Background: Neural tube defects (NTDs) are the greatest shared severely disabling birth defects, they resulted from compound and many etiologies in which both hereditary, life style and ecological factors appear to be convoluted. Objective: To study the role congenital cytomegalovirus and the biomarker Protein 53 (p 53) in pathogenesis of neural tube defects. Patients and Methods: This is a cross sectional comparative study done on 47 mothers of different age group and their babies who have NTD and 47 mothers with their healthy babies at AL-Batool Teaching Hospital/ Diyala/ Iraq from Sept 2017 to May 2018. Rapid serological test to detect anti- CMV IgG and IgM Abs for all case and control groups and their mothers, together with ELISA test to detect P53. The statistical analysis of data was achieved by using SPSS V.20. Results: There was high rate of anti- CMV IgG Abs in NTD cases and their mothers ( n= 10,21.3%, p value= 0.08), out of them, one case had positive anti-IgM Abs together with his mother, whereas in control group, anti CMV IgG was positive in 4(8.5%)in both mothers and their healthy babies with no anti IgM detected. P53 titer is higher to a significant level ( p<0.05) in the mother and their NTD affected baby than control groups ( corresponding babies and mothers). Conclusion: CMV virus might be an important cause of NTD and p53 is a likely to be involved in pathogenesis of NTD.

Effect of periconceptional folic acid supplementation on the risk of neural tube defects associated with a previous spontaneous abortion or maternal first-trimester fever.

Does maternal periconceptional no folic acid supplementation have an increased risk of neural tube defects (NTDs) associated with previous spontaneous abortion or first-trimester fever? Maternal periconceptional no folic acid supplementation can increase the risk of NTDs associated with previous spontaneous abortion or first-trimester fever, independent of known confounding factors. Maternal periconceptional folic acid deficiency can increase the risk of NTDs. However, whether an interaction between periconceptional no folic acid supplementation and history of spontaneous abortion or first-trimester fever may have an increased risk of NTDs remains unknown. A population-based case-control study was performed including 104 nuclear families with offspring with NTDs and 100 control families with normal offspring between 1993 and 2002. We investigated the potential interaction between periconceptional no folic acid use and a maternal history of spontaneous abortion or first-trimester fever in the risk for NTDs. Information on exposure factors was obtained at the onset of pregnancy, and pregnancy outcomes were collected during the first week after delivery or at the time of termination of the pregnancy. A multivariate logistic regression analysis was performed. The interaction between periconceptional no folic acid use and a maternal history of spontaneous abortion markedly increased the risk of NTDs (adjusted odds ratio (aOR) 18.68, 95% CI, 4.43-78.76) after adjusting for potential confounding factors. The interaction coefficient was found to be 2.08, higher than 1, indicating that there is a significant interaction between two factors. Mothers who did not take periconceptional folic acid and had first-trimester fever had an increased risk of NTDs (aOR 21.81, 95% CI, 8.81-80.73). However, the interaction coefficient was found to be 0.62, less than 1, indicating that there is no significant interaction between two factors. A potential limitation was that the interval between the previous spontaneous abortion and the beginning of the subsequent pregnancy could not be estimated accurately, but was at least 1year or more. We emphasize that a previous spontaneous abortion may represent a first occurrence of NTDs rather than be the cause of NTDs. Our findings indicate that mothers with a history of spontaneous abortion are ideal candidates for periconceptional folic acid supplementation. This work was supported by National Natural Science Foundation of China (41871360) and Danone Nutrition Center for Dietary Nutrition Research and Education Foundation (DIC2015-05). There are no competing interests to declare.

Clinical Extrapolation of the Effects of Dolutegravir and Other HIV Integrase Inhibitors on Folate Transport Pathways.

Preliminary analysis of ongoing birth surveillance study identified evidence of potential increased risk for neural tube defects (NTDs) in newborns associated with exposure to dolutegravir at the time of conception. Folate deficiency is a common cause of NTDs. Dolutegravir and other HIV integrase inhibitor drugs were evaluated in vitro for inhibition of folate transport pathways: proton-coupled folate transporter (PCFT), reduced folate carrier (RFC), and folate receptor α (FRα)-mediated endocytosis. Inhibition of folate transport was extrapolated to the clinic by using established approaches for transporters in intestine, distribution tissues, and basolateral and apical membranes of renal proximal tubules (2017 FDA Guidance). The positive controls, methotrexate and pemetrexed, demonstrated clinically relevant inhibition of PCFT, RFC, and FRα in folate absorption, distribution, and renal sparing. Valproic acid was used as a negative control that elicits folate-independent NTDs; valproic acid did not inhibit PCFT, RFC, or FRα At clinical doses and exposures, the observed in vitro inhibition of FRα by dolutegravir and cabotegravir was not flagged as clinically relevant; PCFT and RFC inhibition was not observed in vitro. Bictegravir inhibited both PCFT and FRα, but the observed inhibition did not reach the criteria for clinical relevance. Elvitegravir and raltegravir inhibited PCFT, but only raltegravir inhibition of intestinal PCFT was flagged as potentially clinically relevant at the highest 1.2-g dose (not the 400-mg dose). These studies showed that dolutegravir is not a clinical inhibitor of folate transport pathways, and it is not predicted to elicit clinical decreases in maternal and fetal folate levels. Clinically relevant HIV integrase inhibitor drug class effect on folate transport pathways was not observed. SIGNIFICANCE STATEMENT: Preliminary analysis of ongoing birth surveillance study identified evidence of potential increased risk for neural tube defects (NTDs) in newborns associated with exposure to the HIV integrase inhibitor dolutegravir at the time of conception; folate deficiency is a common cause of NTDs. Dolutegravir and other HIV integrase inhibitor drugs were evaluated in vitro for inhibition of the major folate transport pathways: proton-coupled folate transporter, reduced folate carrier, and folate receptor α-mediated endocytosis. The present studies showed that dolutegravir is not a clinical inhibitor of folate transport pathways, and it is not predicted to elicit clinical decreases in maternal and fetal folate levels. Furthermore, clinically relevant HIV integrase inhibitor drug class effect on folate transport pathways was not observed.

Nutritional status among women whose pregnancy outcome was afflicted with neural tube defects in Tigray region of Ethiopia

BackgroundNutritional deficiency in pregnant women is a confirmed cause of neural tube defects (NTDs). Alongside to this background, We sought to determine the nutritional status and level of awareness on the issue of the NTDs as well as folic acid (FA) utilization among women who born infants with NTDs in Tigray region of Ethiopia. MethodA standard interviewer and a food frequency questionnaire was used to obtain information from mothers of cases with neural tube defects (n = 205) and their controls (n = 412). Demographic information, weekly food frequency consumption, information on awareness on the issue of the NTDs as well as folic acid (FA) use was collected. ResultThe mean age of the mothers of the cases and controls was 26.5 years (range 17–43 years) and 26.05 years (range 18–40 years), respectively. Approximately 92.2% (189/205) of the cases and 90.5% (373/412) control mothers do not know the term folic acid (FA). Notably, all participant mothers (100%) did not understand that NTDs are a serious health problem associated with inadequate intake of FA and none of them used FA prior to conception. Food frequency analysis revealed that except for cereals (p = 0.12) and milk products (p = 0.8), the proportion of the consumed food type within seven days recalls period showed a statistically significant difference (p < 0.05) as compared with controls. The dietary diversity score assessment showed those attained low and high dietary diversity score were a statistically significant difference (p = 0.0003) and (p = 0.0002) respectively) as compared with controls, but the medium dietary diversity score no significant variation was found (p = 0.35). ConclusionThis study has shown none of the study participants do understand that NTDs are a serious health problem associated with inadequate intake of FA. Dietary diversity score was significantly associated with incidence of NTDs. This Ethiopian study also highlighted the need of considering the basic food in future programs of food fortification with folic acid, preconceptional folic acid supplementation and adequate dietary intake counseling. Advance research is required to find out the gene-nutrient and gene environment interactions, as well as particular causative factors associated with NTDs in Ethiopia.

LRP2 gene variants and their haplotypes strongly influence the risk of developing neural tube defects in the fetus: a family-triad study from South India.

Neural tube defects (NTDs) are the leading cause of infant deaths worldwide. Lipoprotein related receptor 2 (LRP2) has been shown to play a crucial role in neural tube development in mouse models. However, the role of LRP2 gene in the development of human NTDs is not yet known. In view of this, family-based triad approach has been followed considering 924 subjects comprising 124 NTD case-parent trios and 184 control-parent trios diagnosed at Institute of Genetics and Hospital for Genetic Diseases, Hyderabad. Blood and tissue samples were genotyped for rs3755166 (-G759A) and rs2544390 (C835T) variants of LRP2 gene for their association with NTDs. Assessment of maternal-paternal genotype incompatibility risk for NTD revealed 3.77-folds risk with a combination of maternal GA and paternal GG genotypes (GAxGG = GA,p < 0.001), while CT genotypes of both the parents showed 4.19-folds risk for NTDs (CTxCT = CT,p = 0.009). Haplotype analysis revealed significant risk of maternal A-T (OR = 4.48,p < 0.001) and paternal G-T haplotypes (OR = 5.22,p < 0.001) for NTD development. Further, linkage analysis for parent-of-origin effects (POE) also revealed significant transmission of maternal 'A' allele (OR = 2.33,p = 0.028) and paternal 'T' allele (OR = 6.00,p = 0.016) to NTDs. Analysis of serum folate and active-B12 levels revealed significant association with LRP2 gene variants in the causation of NTDs. In conclusion, the present family-based triad study provides the first report on association of LRP2 gene variants with human NTDs.

The Association of Single Nucleotide Polymorphisms of the Iodothyronine Deiodinase Gene in Neural Tube Defects: A Case Control Study

Background/Aim: Although adequate folic acid or multivitamins can prevent up to 70% of neural tube defects (NTDs), the cause of NTDs in some cases remains unknown. Other risk factors are thought to...

Homocysteine and vitamin B12: Other causes of neural tube defects in Eastern Uttar Pradesh and Western Bihar population.

Neural tube defects (NTDs) are congenital malformations with an incidence of 1-10/1000 live births. Homocysteine and vitamin B12 metabolism have been shown to be associated with NTDs. To investigate the status of maternal and neonate's folic acid, homocysteine, and vitamin B12 levels and their association with the risk of development of NTDs in the population of Eastern Uttar Pradeshand Western Bihar, India. This study is a cross-sectional, retrospective study where 96 mothers who either had a first NTD child or had a history of NTD child in the family and 126 neonates with spina bifida were recruited during the period 2012-2015. Eighty-four control mothers whose previous and current pregnancies were normal, and 87 control neonates who had no defects and were within the same age range as the NTD affected neonates, recruited from the department of pediatric surgery, were enrolled in the study. Plasma concentrations of folic acid, vitamin B12, and homocysteine were compared between cases and controls. The folic acid level in the mothers and neonates was within the normal limit. A significant increase in the level of homocysteine in mothers with affected pregnancy and in neonate cases in comparison to control mothers was obseved. Further, a significant decrease in the level of vitamin B12 in mothers with NTD neonates and in the affected neonates was noted. A negative correlation was found between homocysteine and vitamin B12 levels in case and control mothers. A correlation of an increase in serum homocysteine with a decrease in vitamin B12 was seen in mothers of neonates with NTD. A similar observation as made in the neonates with NTDs. It may be suggested that maternal decrease in vitamin B12, in mothers who have normal folic acid may be associated with NTD in their children.

The effect of acetazolamide on intracerebral hemorrhage in stoke patients

Background: 10-20% of all strokes are caused by intracerebral haemorrhage which is the world's leading cause of neural tube defects and the second cause of mortality in the world. The aim of this study was to assessment the effect of acetazolamide in the symptom improvement, decreasing rankin scale and mortality rate in patients with intracerebral haemorrhage.Methods: This is a clinical trial study that has been done on 120 stroke patients which divided randomly in two groups each with 60 patients. Patients in intervention group take acetazolamide 750 mg/day and in control group take placebo. The status of patients investigated by Rankin scale in three times baseline, 72 hours and 3 weeks after Cerebral haemorrhage.Results: Of all patients, 49 (40.8%) were male and 71 (59.1%) were female. Putamen haemorrhage is the most location for cerebral haemorrhage (n = 43, 35.8%). According to the Rankin scale, 53 (44.2%) of patients were in the status 4 “moderately severe disability. Unable to attend to own bodily needs without assistance and unable to walk unassisted” in baseline. In the intervention group based on Rankin scale after 72 hour and three week the recovery rate was significantly more than control group.Conclusions: Acetazolamide can be effective in treatment haemorrhagic stroke, decreasing Rankin scale and mortality rate in patients with cerebral haemorrhage.

Peri-conceptional supplementation of folic acid-knowledge and practices of pregnant women and health providers.

Context:Neural tube defects (NTDs) are one of the most common congenital anomalies. NTDs are preventable if folic acid (FA) is supplemented before and during conception. Knowledge and supplementation of FA by pregnant women as well as it's timely provision by health providers is crucial in reducing the burden of NTDs in the community.Aim:To study the knowledge and supplementation of FA by pregnant women and it's prescription/provision by health providers.Settings and Design:A cross-sectional study was conducted in the block Doiwala, District Dehradun, Uttarakhand.Subjects and Methods:A total of 400 pregnant women and 121 government health providers (5 medical officers, 25 auxiliary nurse midwives [ANMs], and 91 accredited social health activists [ASHAs]) were interviewed on predesigned, pretested questionnaire by study/field investigator.Statistical Analysis Used:Proportion of different variables calculated and Chi-square test with Yates correction was applied.Results:Of 400, 73.50% of women had heard of FA. Overall, knowledge scores suggested intermediate to low level of knowledge about FA. Totally 94.25% of women had planned pregnancies; however, only 4.75% of women reported FA supplementation before conception. This indicates that if these women would have been properly counseled and prescribed FA, they might have taken it. About 60% of medical officers, 4% of ANMs, and 3.3% of ASHAs knew FA deficiency as one of the causes of NTD. None of the health providers reported to be prescribing/counseling FA to pregnant women. FA was out of supply on the block at the time of the study.Conclusions:Knowledge and supplementation practices related with FA are poor.

When folic acid fails: Insights from 20 years of neural tube defect surveillance in South Carolina.

Neural tube defects (NTDs) are the most common of the severe malformations of the brain and spinal cord. Increased maternal intake of folic acid (FA) during the periconceptional period is known to reduce NTD risk. Data from 1046 NTD cases in South Carolina were gathered over 20 years of surveillance. It was possible to determine maternal periconceptional FA use in 615 NTD-affected pregnancies. In 163 occurrent (26.9%) and two recurrent (22%) NTD cases, the mothers reported periconceptional FA use. These women were older and more likely to be white. Maternal periconceptional FA usage was reported in 40.4% of cases of spina bifida with other anomalies but in only 25.2% of isolated spina bifida cases (P = 0.02). This enrichment for associated anomalies was not noted among cases of anencephaly or of encephalocele. Among the 563 subsequent pregnancies to mothers with previous NTD-affected pregnancies, those taking FA had a 0.4% NTD recurrence rate, but the recurrence without FA was 8.5%. NTDs with other associated findings were less likely to be prevented by FA, suggesting there is a background NTD rate that cannot be further reduced by FA. Nonetheless, the majority (73.9%) of NTDs in pregnancies in which the mothers reported periconceptional FA use were isolated NTDs of usual types. Cases in which FA failed in prevention of NTDs provide potential areas for further study into the causation of NTDs. The measures and techniques implemented in South Carolina can serve as an effective and successful model for prevention of NTD occurrence and recurrence.

Drinking water treatment is not associated with an observed increase in neural tube defects in mice

Disinfection by-products (DBPs) arise when natural organic matter in source water reacts with disinfectants used in the water treatment process. Studies have suggested an association between DBPs and birth defects. Neural tube defects (NTDs) in embryos of untreated control mice were first observed in-house in May 2006 and have continued to date. The source of the NTD-inducing agent was previously determined to be a component of drinking water. Tap water samples from a variety of sources were analyzed for trihalomethanes (THMs) to determine if they were causing the malformations. NTDs were observed in CD-1 mice provided with treated and untreated surface water. Occurrence of NTDs varied by water source and treatment regimens. THMs were detected in tap water derived from surface water but not detected in tap water derived from a groundwater source. THMs were absent in untreated river water and laboratory purified waters, yet the percentage of NTDs in untreated river water were similar to the treated water counterpart. These findings indicate that THMs were not the primary cause of NTDs in the mice since the occurrence of NTDs was unrelated to drinking water disinfection.

Epigenetic profiles in children with a neural tube defect; a case-control study in two populations.

Folate deficiency is implicated in the causation of neural tube defects (NTDs). The preventive effect of periconceptional folic acid supplement use is partially explained by the treatment of a deranged folate-dependent one carbon metabolism, which provides methyl groups for DNA-methylation as an epigenetic mechanism. Here, we hypothesize that variations in DNA-methylation of genes implicated in the development of NTDs and embryonic growth are part of the underlying mechanism. In 48 children with a neural tube defect and 62 controls from a Dutch case-control study and 34 children with a neural tube defect and 78 controls from a Texan case-control study, we measured the DNA-methylation levels of imprinted candidate genes (IGF2-DMR, H19, KCNQ1OT1) and non-imprinted genes (the LEKR/CCNL gene region associated with birth weight, and MTHFR and VANGL1 associated with NTD). We used the MassARRAY EpiTYPER assay from Sequenom for the assessment of DNA-methylation. Linear mixed model analysis was used to estimate associations between DNA-methylation levels of the genes and a neural tube defect. In the Dutch study group, but not in the Texan study group we found a significant association between the risk of having an NTD and DNA methylation levels of MTHFR (absolute decrease in methylation of −0.33% in cases, P-value = 0.001), and LEKR/CCNL (absolute increase in methylation: 1.36% in cases, P-value = 0.048), and a borderline significant association for VANGL (absolute increase in methylation: 0.17% in cases, P-value = 0.063). Only the association between MTHFR and NTD-risk remained significant after multiple testing correction. The associations in the Dutch study were not replicated in the Texan study. We conclude that the associations between NTDs and the methylation of the MTHFR gene, and maybe VANGL and LEKKR/CNNL, are in line with previous studies showing polymorphisms in the same genes in association with NTDs and embryonic development, respectively.

Altered methylation of IGF2 DMR0 is associated with neural tube defects

Neural tube defects (NTDs) are serious congenital malformation of fusion failure of the neural tube during early embryogenesis. DNA methylation disorders have been found in NTD-affected fetuses, and are correlated to the risk of NTDs. The insulin-like growth factor 2 (IGF2) gene, maternally imprinted, has a key role in fetal development. IGF2 transcription is partly controlled by differentially methylated regions (DMRs) 0 and 2. To assess whether disturbed methylation pattern increases the incidence of NTDs, we employed matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to quantify CpG methylation levels of DMR2 and 0 in fetuses with or without NTDs. We found that the methylation level of IGF2 DMR0 increased significantly in the brain tissues of NTD-affected fetuses. And hypermethylation of DMR0 was associated with an increased risk of NTDs, with an odds ratio of 5.375 (95 % CI: 1.447-19.965; p = 0.007). IGF2 mRNA expression was negatively correlated with the methylation level of DMR0 (R (2) = 0.893; p = 0.000) in HCT15 cells. These results highlights that IGF2 DMR0 hypermethylation is a potential risk factor of NTD, and IGF2 gene is a promising candidate gene to study for a greater understanding of the cause of NTDs.