Maternal hyperhomocysteinaemia is a risk factor for congenital heart disease

Association of maternal and paternal risk factors with risk of congenital heart disease in infants: a case-control study

OBJECTIVE

We aimed to explore maternal and paternal risk factors with risk of congenital heart disease in infants.

METHODS

A total of 125 congenital heart disease (CHD) infants and 125 controls were included in Heping Hospital Affiliated to Changzhi Medical College, Shanxi, China. Subjects were diagnosed between Jan 1, 2016 and Dec 31, 2021 in the present study. All the characteristics were collected with questionnaire by face-to-face interview, including maternal and paternal risk factors. Conditional logistic regression was conducted to explore the risk factors with risk of congenital heart disease in infants.

RESULTS

For maternal risk factors, we found that age, number of pregnancies, systolic blood pressure (SBP), diastolic blood pressure (DBP), and body mass index (BMI) were risk factors for CHD infants, and the ORs (95%CIs) were 1.15 (1.06-1.23) for age, 1.13 (1.02-1.29) for SBP, 1.06 (1.02-1.18) for DBP, 1.22 (1.16-1.31) for BMI. Compared with one pregnancy, the ORs (95%CIs) were 1.17 (1.05-1.29) for two pregnancies and 1.25 (1.16-1.47) for more pregnancies. For paternal risk factors, we found that age (OR = 1.07, 95%CI = 1.01-1.19), smoking (OR = 1.11, 95%CI = 1.03-1.27), drinking (OR = 1.04, 95%CI = 1.02-1.19), and BMI (OR = 1.15, 95%CI = 1.03-1.28) were risk factors for CHD infants.

CONCLUSION

We found that age, number of pregnancies, SBP, DBP, and BMI are maternal risk factors for CHD infants. And age, smoking, drinking, and BMI are paternal risk factors for CHD infants.

The prevalence of thyroid dysfunction and hyperprolactinemia in women with PCOS

Introduction

Ovulatory dysfunction is usually caused by an endocrine disorder, of which polycystic ovary syndrome (PCOS) is the most common cause. PCOS is usually associated with estrogen levels within the normal range and can be characterized by oligo-/anovulation resulting in decreased progesterone levels. It is suggested that decreased progesterone levels may lead to more autoimmune diseases in women with PCOS. In addition, it is often claimed that there is an association between hyperprolactinemia and PCOS. In this large well-phenotyped cohort of women with PCOS, we have studied the prevalence of thyroid dysfunction and hyperprolactinemia compared to controls, and compared this between the four PCOS phenotypes.

Methods

This retrospective cross-sectional study contains data of 1429 women with PCOS and 299 women without PCOS. Main outcome measures included thyroid stimulating hormone (TSH), Free Thyroxine (FT4), and anti-thyroid peroxidase antibodies (TPOab) levels in serum, the prevalence of thyroid diseases and hyperprolactinemia.

Results

The prevalence of thyroid disease in PCOS women was similar to that of controls (1.9% versus 2.7%; P = 0.39 for hypothyroidism and 0.5% versus 0%; P = 0.99 for hyperthyroidism). TSH levels were also similar (1.55 mIU/L versus 1.48 mIU/L; P = 0.54). FT4 levels were slightly elevated in the PCOS group, although within the normal range (18.1 pmol/L versus 17.7 pmol/L; P < 0.05). The prevalence of positive TPOab was similar in both groups (5.7% versus 8.7%; P = 0.12). The prevalence of hyperprolactinemia was similarly not increased in women with PCOS (1.3%% versus 3%; P = 0.05). In a subanalysis of 235 women with PCOS and 235 age- and BMI-matched controls, we found no differences in thyroid dysfunction or hyperprolactinemia. In according to differences between PCOS phenotypes, only the prevalence of subclinical hypothyroidism was significantly higher in phenotype B (6.3%, n = 6) compared to the other phenotypes.

Conclusion

Women with PCOS do not suffer from thyroid dysfunction more often than controls. Also, the prevalence of positive TPOab, being a marker for future risk of thyroid pathology, was similar in both groups. Furthermore, the prevalence of hyperprolactinemia was similar in women with PCOS compared to controls.

Association of Maternal Betaine-Homocysteine Methyltransferase (BHMT) and BHMT2 Genes Polymorphisms with Congenital Heart Disease in Offspring

To systematically explore the association of single nucleotide polymorphisms (SNPs) of maternal BHMT and BHMT2 genes with the risk of congenital heart disease (CHD) and its three subtypes including atrial septal defect (ASD), ventricular septal defect (VSD), and patent ductus arteriosus (PDA) in offspring. A hospital-based case-control study involving 683 mothers of CHD children and 740 controls was performed. Necessary exposure information was captured through epidemiological investigation. Totally twelve SNPs of maternal BHMT and BHMT2 genes were detected and analyzed systematically. The study showed that maternal BHMT gene polymorphisms at rs1316753 (CG vs. CC: OR = 1.96 [95% CI 1.41-2.71]; GG vs. CC: OR = 1.99 [95% CI 1.32-3.00]; dominant model: OR = 1.97 [95% CI 1.44-2.68]) and rs1915706 (TC vs. TT: OR = 1.93 [95% CI 1.44-2.59]; CC vs. TT: OR = 2.55 [95% CI 1.38-4.72]; additive model: OR = 1.77 [95% CI 1.40-2.24]) were significantly associated with increased risk of total CHD in offspring. And two haplotypes were observed to be significantly associated with risk of total CHD, including C-C haplotype involving rs1915706 and rs3829809 in BHMT gene (OR = 1.30 [95% CI 1.07-1.58]) and C-A-A-C haplotype involving rs642431, rs592052, rs626105, and rs682985 in BHMT2 gene (OR = 0.71 [95% CI 0.58-0.88]). Besides, a three-locus model involving rs1316753 (BHMT), rs1915706 (BHMT), and rs642431 (BHMT2) was identified through gene-gene interaction analyses (P < 0.01). As for three subtypes including ASD, VSD, and PDA, significant SNPs and haplotypes were also identified. The results indicated that maternal BHMT gene polymorphisms at rs1316753 and rs1915706 are significantly associated with increased risk of total CHD and its three subtypes in offspring. Besides, significant interactions between different SNPs do exist on risk of CHD. Nevertheless, studies with larger sample size in different ethnic populations and involving more SNPs in more genes are expected to further define the genetic contribution underlying CHD and its subtypes.

Different effects of maternal homocysteine concentration, MTHFR and MTRR genetic polymorphisms on the occurrence of fetal aneuploidy

RESEARCH QUESTION

Do maternal homocysteine (Hcy) concentrations, MTHFR and MTRR genes have effects on the occurrence of fetal aneuploidy?

DESIGN

A total of 619 aneuploidy mothers and 192 control mothers were recruited in this study. Differences in distributions of maternal MTHFR 677C>T, MTHFR 1298A>C and MTRR 66A>G genetic polymorphisms and maternal Hcy concentrations between aneuploidy mothers and control mothers were analysed.

RESULTS

The maternal MTHFR 677C>T polymorphism was found to be a risk factor for the occurrence of many fetal non-mosaic aneuploidies studied here, including trisomies 13, 15, 16, 18, 21, 22, TRA and TS. The maternal MTHFR 1298A>C polymorphism was found to be a risk factor specifically associated with the occurrence of fetal trisomy 15 and fetal TS. The maternal MTRR 66A>G polymorphism was found to be a risk factor only specifically associated with the occurrence of fetal trisomy 21. The Hcy concentrations of mothers of trisomies 22, 21, 18, 16, 15 and TS fetuses were significantly higher than the Hcy concentrations of control mothers.

CONCLUSIONS

Overall, data suggested an association between these maternal polymorphisms and the susceptibility of fetal non-mosaic trisomy and Turner syndrome. However, these three maternal polymorphisms had different associations with the susceptibility of different fetal aneuploidies, and the elevated maternal Hcy concentration appeared to be a likely risk factor for fetal Turner syndrome and fetal trisomies.

Maternal micronutrient deficiency and congenital heart disease risk: A systematic review of observational studies

BACKGROUND

Congenital anomalies affect over 2% of pregnancies, with congenital heart disease (CHD) the most common. Understanding of causal factors is limited. Micronutrients are essential trace elements with key roles in growth and development. We aimed to investigate whether maternal micronutrient deficiencies increase the risk of fetal CHD through systematic review of published literature.

METHOD

We performed a systematic review registered at PROSPERO as CRD42021276699. Ovid-MEDLINE, Ovid-EMBASE, and Cochrane Library were searched from their inception until September 7, 2021. Case control trials were included with a population of biological mothers of fetuses with and without CHD. The exposure was maternal micronutrient level measured in pregnancy or the postpartum period. Data extraction was performed by one author and checked by a second. Risk of bias assessment was performed according to the Scottish Intercollegiate Guidelines Network guidance. We performed a narrative synthesis for analysis.

RESULTS

726 articles were identified of which 8 met our inclusion criteria. Final analysis incorporated data from 2,427 pregnancies, 1,199 of which were complicated by fetal CHD assessing 8 maternal micronutrients: vitamin D, vitamin B12, folate, vitamin A, zinc, copper, selenium, and ferritin. Studies were heterogenous with limited sample sizes and differing methods and timing of maternal micronutrient sampling. Definitions of deficiency varied and differed from published literature. Published results were contradictory.

CONCLUSION

There is not enough evidence to confidently conclude if maternal micronutrient deficiencies increase the risk of fetal CHD. Further large-scale prospective study is required to answer this question.

The UA Doppler Index, Plasma HCY, and Cys C in Pregnancies Complicated by Congenital Heart Disease of the Fetus

Background: Congenital heart disease/defect (CHD) is one of the most common congenital disabilities. Early diagnosis of CHD can improve the prognosis of newborns with CHD. The aim of this study was to evaluate the relationship between the factors and the onset of fetal congenital heart disease by measuring fetal umbilical artery (UA) Doppler index, maternal HCY, and Cys C levels during pregnancy. Methods: This retrospective study analyzed 202 fetuses with CHD, including 77 cases (39.1%) of simple CHD and 120 cases (60.9%) of complex CHD. Singleton pregnant women who were examined at the same time and whose malformation screening did not suggest any structural abnormalities in the fetus were assigned to the control group (n = 400). The UA Doppler index, plasma HCY, and Cys C levels were compared among the pregnant women across the three groups, and logistic regression analysis was performed on statistically significant markers. The ROC of UA S/D, PI, RI, HCY, and Cys C were plotted, and the area under the ROC (AUC) was calculated. Results: The UA S/D, PI, and RI in the complex CHD group were significantly higher than those in the control group (p < 0.05). The levels of HCY and Cys C in the CHD group were significantly higher than those in the control group (p < 0.05). HCY and S/D revealed a positive correlation (r = 0.157), and the difference was statistically significant (p < 0.001). Cys C and S/D were positively correlated (r = 0.131), and the difference was statistically significant (p < 0.05). The levels of UA Doppler indices, maternal plasma HCY, and Cys C were elevated in fetuses with CHD. The AUC of the combined test of the UA index, HCY, and Cys C was higher than that of each individual test. Conclusions: Elevated levels of the UA doppler indices, HCY, and Cys C during pregnancy are positively associated with the development of congenital heart disease in offspring. The combination of HCY and Cys C was the most efficient test for the diagnosis of CHD. We are the first to report that plasma Cys C levels of women pregnant with fetuses with CHD were higher than those of women pregnant with normal fetuses.

Periconception Red Blood Cell Folate and Offspring Congenital Heart Disease : Nested Case-Control and Mendelian Randomization Studies

BACKGROUND

Periconception folic acid supplementation has been suggested to protect against congenital heart disease (CHD), but the association between maternal red blood cell (RBC) folate, the gold-standard biomarker of folate exposure, and subsequent offspring CHD risk is lacking.

OBJECTIVE

To quantify the association between periconception maternal RBC folate and offspring CHD risk.

DESIGN

Prospective, nested, case-control study and 1-sample Mendelian randomization. (ClinicalTrials.gov: NCT02737644).

SETTING

29 maternity institutions in 12 districts of Greater Shanghai, China.

PARTICIPANTS

All 197 mothers of offspring with CHD and 788 individually matched mothers of unaffected offspring from the SPCC (Shanghai Preconception Cohort).

MEASUREMENTS

Maternal RBC folate was measured before or at early pregnancy. Odds ratios [ORs] were estimated using conditional logistic regression after adjustment for covariates. Mendelian randomization was done using the methylenetetrahydrofolate reductase (MTHFR) C677T as the genetic instrument.

RESULTS

Case patients had lower median maternal RBC folate concentrations than control participants (714 nmol/L [interquartile range, 482 to 1008 nmol/L] vs. 788 nmol/L [557 to 1094 nmol/L]). Maternal RBC folate concentrations were inversely associated with offspring CHD (adjusted OR per 100 nmol/L, 0.93 [95% CI, 0.89 to 0.99]). The adjusted OR for mothers with periconception RBC folate of 906 nmol/L or more (vs. <906 nmol/L) was 0.61 (CI, 0.40 to 0.93). Mendelian randomization showed that each 100-nmol increase in maternal RBC folate concentrations was significantly associated with reduced offspring CHD risk (OR, 0.75 [CI, 0.61 to 0.92]).

LIMITATION

Potential confounding due to unmeasured covariates in the nested case-control study.

CONCLUSION

Higher maternal RBC folate is associated with reduced offspring CHD risk. For primary CHD prevention, higher target RBC folate levels than currently recommended for neural tube defect prevention may be needed and warrant further study.

PRIMARY FUNDING SOURCE

National Key Research and Development Program of China, National Natural Science Foundation of China, China Postdoctoral Science Foundation, and Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences.

Association of MTHFD1 gene polymorphisms and maternal smoking with risk of congenital heart disease: a hospital-based case-control study

Background

MTHFD1 gene may affect the embryonic development by elevated homocysteine levels, DNA synthesis and DNA methylation, but limited number of genetic variants of MTHFD1 gene was focused on the association with congenital heart disease (CHD). This study examined the role of MTHFD1 gene and maternal smoking on infant CHD risk, and investigated their interaction effects in Chinese populations.

Methods

A case-control study of 464 mothers of CHD infants and 504 mothers of health controls was performed. The exposures of interest were maternal tobacco exposure, single nucleotide polymorphisms (SNPs) of maternal MTHFD1 gene. The logistic regression model was used for accessing the strength of association.

Results

Mothers exposed to secondhand smoke during 3 months before pregnancy (adjusted odds ratio [aOR] = 1.56; 95% confidence interval [CI]: 1.13–2.15) and in the first trimester of pregnancy (aOR = 2.24; 95%CI: 1.57–3.20) were observed an increased risk of CHD. Our study also found that polymorphisms of maternal MTHFD1 gene at rs1950902 (AA vs. GG: aOR = 1.73, 95% CI: 1.01–2.97), rs2236222 (GG vs. AA: aOR = 2.38, 95% CI: 1.38–4.12), rs1256142 (GA vs.GG: aOR = 1.57, 95% CI: 1.01–2.45) and rs11849530 (GG vs. AA: aOR = 1.68, 95% CI: 1.02–2.77) were significantly associated with higher risk of CHD. However, we did not observe a significant association between maternal MTHFD1 rs2236225 and offspring CHD risk. Furthermore, we found the different degrees of interaction effects between polymorphisms of the MTHFD1 gene including rs1950902, rs2236222, rs1256142, rs11849530 and rs2236225, and maternal tobacco exposure.

Conclusions

Maternal polymorphisms of MTHFD1 gene, maternal tobacco exposure and their interactions are significantly associated with the risk of CHD in offspring in Han Chinese populations. However, more studies in different ethnic populations with a larger sample and prospective designs are required to confirm our findings.

Trial registration

Registration number: ChiCTR1800016635.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04419-2.

Environmental Exposures and Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital abnormality worldwide, affecting 8 to 12 infants per 1000 births globally and causing >40% of prenatal deaths. However, its causes remain mainly unknown, with only up to 15% of CHD cases having a determined genetic cause. Exploring the complex relationship between genetics and environmental exposures is key in understanding the multifactorial nature of the development of CHD. Multiple population-level association studies have been conducted on maternal environmental exposures and their association with CHD, including evaluating the effect of maternal disease, medication exposure, environmental pollution, and tobacco and alcohol use on the incidence of CHD. However, these studies have been done in a siloed manner, with few examining the interplay between multiple environmental exposures. Here, we broadly and qualitatively review the current literature on maternal and paternal prenatal exposures and their association with CHD. We propose using the framework of the emerging field of the exposome, the environmental complement to the genome, to review all internal and external prenatal environmental exposures and identify potentiating or alleviating synergy between exposures. Finally, we propose mechanistic pathways through which susceptibility to development of CHD may be induced via the totality of prenatal environmental exposures, including the interplay between placental and cardiac development and the internal vasculature and placental morphology in early stages of pregnancy.

An update on the CHDGKB for the systematic understanding of risk factors associated with non-syndromic congenital heart disease

The Congenital Heart Disease Genetic Knowledge Base (CHDGKB) was established in 2020 to provide comprehensive knowledge about the genetics and pathogenesis of non-syndromic CHD (NS-CHD). In addition to the genetic causes of NS-CHD, environmental factors such as maternal drug use and gene-environment interactions can also lead to CHD. There is a need to integrate this information into a platform for clinicians and researchers to better understand the overall risk factors associated with NS-CHD. The updated CHDGKB contains the genetic and non-genetic risk factors from over 4200 records from PubMed that was manually curated to include the information associated with NS-CHD. The current version of CHDGKB, named CHD-RF-KB (KnowledgeBase for non-syndromic Congenital Heart Disease-associated Risk Factors), is an important tool that allows users to evaluate the recurrence risk and prognosis of NS-CHD, to guide treatment and highlight the precautions of NS-CHD. In this update, we performed extensive functional analyses of the genetic and non-genetic risk information in CHD-RF-KB. These data can be used to systematically understand the heterogeneous relationship between risk factors and NS-CHD phenotypes.

Association of maternal folate use and reduced folate carrier gene polymorphisms with the risk of congenital heart disease in offspring

Although it is generally recognized that genetic and environmental factors are associated with the risk of congenital heart disease (CHD), the mechanism remains largely uncertain. This study aimed to investigate the association of maternal folate use, the time when folate use was started, and polymorphisms of the reduced folate carrier (RFC1) gene with the risk of CHD in offspring of Chinese descent, which can help provide new insight into the etiology of folate-related birth defects. A case-control study of 683 mothers of CHD patients and 740 mothers of healthy children was performed. The present study showed that mothers who did not use folate were at a significantly increased risk of CHD (OR=2.04; 95% CI: 1.42-2.93). When compared with those who started using folate prior to conception, mothers who started using folate from the first trimester of pregnancy (OR=1.90; 95% CI: 1.43-2.54) or from the second trimester of pregnancy (OR=8.92; 95% CI: 4.20-18.97) had a significantly higher risk of CHD. Maternal RFC1 gene polymorphisms at rs2236484 (AG vs AA: OR=1.79 [95% CI: 1.33-2.39]; GG vs AA: OR=1.64 [95% CI: 1.15-2.35]) and rs2330183 (CT vs CC: OR=1.54 [95% CI: 1.14-2.09]) were also significantly associated with CHD risk. Additionally, the risk of CHD was significantly decreased among mothers who had variant genotypes but used folate when compared with those who had variant genotypes and did not use folate.Conclusion: In those of Chinese descent, maternal folate use and the time when use started are significantly associated with the risk of CHD in offspring. Furthermore, maternal folate supplementation may help to offset some of the risks of CHD in offspring due to maternal RFC1 genetic variants. What is Known: • Folate use could help prevent CHD, but the relationship between the time when folate use is started and CHD has not received sufficient attention. • Studies have assessed the associations of folate metabolism-related genes with CHD, but genes involved in cellular transportation of folate, such as the RFC1 gene, have not garnered enough attention. What is New: • In those of Chinese descents, the time when folate use is started is significantly associated with the risk of CHD in offspring. • Maternal RFC1 polymorphisms were significantly associated with the risk of CHD. • Folate supplementation may help to offset some risks of CHD due to RFC1 genetic variants.

Association of homocysteine with IVF/ICSI outcomes stratified by MTHFR C677T polymorphisms: a prospective cohort study

RESEARCH QUESTION

What is the association between homocysteine (Hcy) and IVF/intracytoplasmic sperm injection (ICSI) outcomes, stratified by methylenetetrahydrofolate reductase (MTHFR) C677T polymorphisms?

DESIGN

This prospective cohort study recruited 1011 infertile women undergoing IVF/ICSI treatment for the first time at the International Peace Maternity and Child Health Hospital between June 2015 and March 2018.

RESULTS

The concentration of total serum Hcy was significantly negatively associated with clinical pregnancy and implantation rate. When adjusted for maternal and paternal age and educational level, maternal body mass index, and FSH and oestradiol concentrations, logistic regression analysis showed that women with higher Hcy had a higher risk of unsuccessful pregnancy. After stratification by MTHFR C677T polymorphisms and adjustment for confounding factors, a higher risk of unsuccessful pregnancy and a significantly lower implantation rate only existed in women with higher Hcy concentration in the MTHFR C677T TT genotype. There was no significant association between Hcy concentrations and other ovarian stimulation outcomes (oocytes retrieved, metaphase II stage oocytes, fertilization rate, cleavage rate, high-quality embryo rate) or neonatal outcomes (preterm birth, gestational age at delivery, Caesarean section, birthweight, small for gestational age, large for gestational age or birth defects).

CONCLUSIONS

Hcy is highly negatively associated with clinical pregnancy and implantation rate during the first IVF/ICSI cycle, especially in women carrying the MTHFR C677T TT genotype. Other factors with impacts on reproductive outcomes, such as stage of embryo transferred, other factors involved in folate metabolism, preimplantation genetic testing, etc., should be taken into account in further research.

Paternal genetic variants and risk of obstructive heart defects: A parent-of-origin approach

Previous research on risk factors for obstructive heart defects (OHDs) focused on maternal and infant genetic variants, prenatal environmental exposures, and their potential interaction effects. Less is known about the role of paternal genetic variants or environmental exposures and risk of OHDs. We examined parent-of-origin effects in transmission of alleles in the folate, homocysteine, or transsulfuration pathway genes on OHD occurrence in offspring. We used data on 569 families of liveborn infants with OHDs born between October 1997 and August 2008 from the National Birth Defects Prevention Study to conduct a family-based case-only study. Maternal, paternal, and infant DNA were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. Relative risks (RR), 95% confidence interval (CI), and likelihood ratio tests from log-linear models were used to estimate the parent-of-origin effect of 877 SNPs in 60 candidate genes in the folate, homocysteine, and transsulfuration pathways on the risk of OHDs. Bonferroni correction was applied for multiple testing. We identified 3 SNPs in the transsulfuration pathway and 1 SNP in the folate pathway that were statistically significant after Bonferroni correction. Among infants who inherited paternally-derived copies of the G allele for rs6812588 in the RFC1 gene, the G allele for rs1762430 in the MGMT gene, and the A allele for rs9296695 and rs4712023 in the GSTA3 gene, RRs for OHD were 0.11 (95% CI: 0.04, 0.29, P = 9.16x10^-7), 0.30 (95% CI: 0.17, 0.53, P = 9.80x10^-6), 0.34 (95% CI: 0.20, 0.57, P = 2.28x10^-5), and 0.34 (95% CI: 0.20, 0.58, P = 3.77x10^-5), respectively, compared to infants who inherited maternally-derived copies of the same alleles. We observed statistically significant decreased risk of OHDs among infants who inherited paternal gene variants involved in folate and transsulfuration pathways.

Obstructive heart defects are birth defects that cause obstruction to the blood flow of the developing heart. Common OHDs include coarctation of the aorta, aortic stenosis and pulmonary stenosis. While there is a fair amount of literature indicating an association between maternal genetic variants and OHDs, less is known about the role of paternal genetic variants in the etiology of OHDs. We used a genotype clustering algorithm, SNPMClust, that was developed in-house at the Arkansas Center for Birth Defects Research and Prevention to study the role of paternal genetic variants in the folate, homocysteine and transsulfuration pathways. Maternal, paternal, and infant DNA specimens were collected from participants of the National Birth Defects Prevention Study, a large population-based case-control study in the United States, and were genotyped using an Illumina Golden Gate custom single nucleotide polymorphism (SNP) panel. We identified 4 SNPs in the folate and transsulfuration pathways, rs6812588, rs1762430, rs9296695, and rs4712023, that were associated with a statistically significant decreased risk of OHDs for infants who inherited a paternally-derived copy of the variant allele compared to infants who inherited a maternal copy of the variant allele. In conclusion, we observed a significantly decreased risk and less epigenetic influence of paternal genetic variants on OHDs compared to maternally-derived variants.

Epigenetics of the developing and aging brain: Mechanisms that regulate onset and outcomes of brain reorganization

Brain development is a life-long process that encompasses several critical periods of transition, during which significant cognitive changes occur. Embryonic development, puberty, and reproductive senescence are all periods of transition that are hypersensitive to environmental factors. Rather than isolated episodes, each transition builds upon the last and is influenced by consequential changes that occur in the transition before it. Epigenetic marks, such as DNA methylation and histone modifications, provide mechanisms by which early events can influence development, cognition, and health outcomes. For example, parental environment influences imprinting patterns in gamete cells, which ultimately impacts gene expression in the embryo which may result in hypersensitivity to poor maternal nutrition during pregnancy, raising the risks for cognitive impairment later in life. This review explores how epigenetics induce and regulate critical periods, and also discusses how early environmental interactions prime a system towards a particular health outcome and influence susceptibility to disease or cognitive impairment throughout life.

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.

Environmental Risk Factors for Congenital Heart Disease

Congenital heart disease (CHD) has many forms and a wide range of causes. Clinically, it is important to understand the causes. This allows estimation of recurrence rate, guides treatment options, and may also be used to formulate public health advice to reduce the population prevalence of CHD. The recent advent of sophisticated genetic and genomic methods has led to the identification of more than 100 genes associated with CHD. However, despite these great strides, to date only one-third of CHD cases have been shown to have a simple genetic cause. This is because CHD can also be caused by oligogenic factors, environmental factors, and/or gene-environment interaction. Although solid evidence for environmental causes of CHD have been available for almost 80 years, it is only very recently that the molecular mechanisms for these risk factors have begun to be investigated. In this review, we describe the most important environmental CHD risk factors, and what is known about how they cause CHD.

Analysis of MTR and MTRR Gene Polymorphisms in Chinese Patients With Ventricular Septal Defect

Background:

Congenital heart defects (CHDs) are the most common birth defects and ventricular septal defects (VSDs) are one of the most common types of CHDs. Genes involved in homocysteine/folate metabolism may play important roles in CHDs. Methionine synthase and methionine synthase reductase (MTRR) are key regulatory enzymes involved in the metabolic pathway of homocysteine.

Methods:

We investigated whether a polymorphism (A2756G) of the methionine synthase and 2 polymorphisms (A66G and C524T) of the MTRR gene are associated with VSDs. A total of 183 children with VSDs and 201 healthy children were studied.

Results:

The polymorphisms were detected by polymerase chain reaction amplification and sequencing of the amplified product. Significant differences in the distributions of the A66G and C524T alleles were observed between VSD cases and controls, and a slightly increased risk of VSDs was associated with either of the 66AG, 524CT, and 524TT genotypes [odds ratios (OR)=1.796, 1.909, and 2.088, respectively]. The genotype frequency of 66AG in VSDs patients was significantly different from those of controls (ORs=3.147). In addition, the combined 66AG/524CT and 66GG/524TT in VSDs had ORs 2.937 and 5.344, respectively.

Conclusions:

MTRR A66G and C524T polymorphisms are associated with increased risk of VSDs.

Modulation of ADAR mRNA expression in patients with congenital heart defects

Adenosine (A) to inosine (I) RNA editing is a hydrolytic deamination reaction catalyzed by the adenosine deaminase (ADAR) enzyme acting on double-stranded RNA. This posttranscriptional process diversifies a plethora of transcripts, including coding and noncoding RNAs. Interestingly, few studies have been carried out to determine the role of RNA editing in vascular disease. The aim of this study was to determine the potential role of ADARs in congenital heart disease. Strong downregulation of ADAR2 and increase in ADAR1 expression was observed in blood samples from congenital heart disease (CHD) patients. The decrease in expression of ADAR2 was in line with its downregulation in ventricular tissues of dilated cardiomyopathy patients. To further decipher the plausible regulatory pathway of ADAR2 with respect to heart physiology, miRNA profiling of ADAR2 was performed on tissues from ADAR2-/- mouse hearts. Downregulation of miRNAs (miR-29b, miR-405, and miR-19) associated with cardiomyopathy and cardiac fibrosis was observed. Moreover, the upregulation of miR-29b targets COL1A2 and IGF1, indicated that ADAR2 might be involved in cardiac myopathy. The ADAR2 target vascular development associated protein-coding gene filamin B (FLNB) was selected. The editing levels of FLNB were dramatically reduced in ADAR2^-/- mice; however, no observable changes in FLNB expression were noted in ADAR2^-/- mice compared to wild-type mice. This study proposes that sufficient ADAR2 enzyme activity might play a vital role in preventing cardiovascular defects.

Vitamin D and metabolic disturbances in polycystic ovary syndrome (PCOS): A cross-sectional study

OBJECTIVE

To compare vitamin D status in women with PCOS versus fertile women and subsequently evaluate the association between vitamin D status and metabolic disturbances in PCOS women.

METHODS

We conducted a cross-sectional comparison study of 639 women with PCOS and 449 fertile women. Serum 25-hydroxyvitamin D (25(OH)D) was stratified into a severe deficient (< 25 nmol/l), insufficient (25-50 nmol/l), moderate (50-75 nmol/l) and adequate (> 75 nmol/l) status. The main outcome measures were the difference in vitamin D status between PCOS and fertile women, and the association between serum 25(OH)D and metabolic disturbances in PCOS women only.

RESULTS

Serum 25(OH)D was significantly lower in PCOS women compared to fertile controls (mean 25(OH)D of 49.0 nmol/l versus 64.5 nmol/l). An adjusted significant difference was seen between serum 25(OH)D and homeostasis model assessment (HOMA-IR) (β = 0.76; 95% CI: 0.63-0.91; p < 0.01), HDL-cholesterol (β = 0.20; 95% CI: 0.05-0.60, p < 0.01) and apolipoprotein A1 (β = 26.2; 95% CI: 7.5-45.0, p < 0.01) between the highest vitamin D group compared to the lowest vitamin D group.

CONCLUSIONS

This study demonstrates that women with PCOS have a significantly lower serum 25(OH)D compared to fertile controls. A compromised vitamin D status in PCOS women is associated with a higher HOMA-IR and an unfavourable lipid profile. Large randomized controlled trials are necessary to explore the causality of this linkage.

Association Between Maternal Serum Folate Concentrations in the First Trimester and the Risk of Birth Defects: The Hokkaido Study of Environment and Children's Health

Background

Low red blood cell folate concentrations during early pregnancy might cause neural tube defects. However, the association between folate concentrations and birth defects of other neural crest cell-derived organs remains unknown. We investigated the associations between birth defects and first-trimester serum folate concentrations in a birth-cohort study in Japan.

Methods

In total, 14,896 women who were prior to 13 weeks of gestation were enrolled from 2003 through 2012. Birth defect information was obtained from medical records and questionnaires. The association between folate levels in the first trimester and birth defects categorized as ICD-10 cord defects and neural crest cell-derived organ defects was examined. The crude and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) per log-transformed folate concentration were calculated using logistic regression.

Results

Blood samples were obtained at a mean of 10.8 weeks of gestation. Median serum folate level was 16.5 (interquartile range, 13.4–21.5) nmol/L, and the deficiency level (less than 6.8 nmol/L) was 0.7%. There were 358 infants with birth defects. The adjusted odds ratio for any birth defect, ventricular septal defects, and cleft lip was 0.99 (95% CI, 0.74–1.32), 0.63 (95% CI, 0.30–1.33), and 4.10 (95% CI, 0.96–17.58), respectively. There were no significant associations between first-trimester maternal serum folate and the risk of birth defects.

Conclusions

We were unable to demonstrate a relationship between maternal serum folate in the first trimester and birth defects. Potential confounding factors may have influenced our results.

A parent-of-origin analysis of paternal genetic variants and increased risk of conotruncal heart defects

The association between conotruncal heart defects (CTHDs) and maternal genetic and environmental exposures is well studied. However, little is known about paternal genetic or environmental exposures and risk of CTHDs. We assessed the effect of paternal genetic variants in the folate, homocysteine, and transsulfuration pathways on risk of CTHDs in offspring. We utilized National Birth Defects Prevention Study data to conduct a family-based case only study using 616 live-born infants with CTHDs, born October 1997-August 2008. Maternal, paternal and infant DNA was genotyped using an Illumina® Golden Gate custom single nucleotide polymorphism (SNP) panel. Relative risks (RR) and 95% confidence intervals (CI) from log-linear models determined parent of origin effects for 921 SNPs in 60 candidate genes involved in the folate, homocysteine, and transsulfuration pathways on risk of CTHDs. The risk of CTHD among children who inherited a paternally derived copy of the A allele on GLRX (rs17085159) or the T allele of GLRX (rs12109442) was 0.23 (95%CI: 0.12, 0.42; p = 1.09 × 10^-6 ) and 0.27 (95%CI: 0.14, 0.50; p = 2.06 × 10^-5 ) times the risk among children who inherited a maternal copy of the same allele. The paternally inherited copy of the GSR (rs7818511) A allele had a 0.31 (95%CI: 0.18, 0.53; p = 9.94 × 10^-6 ] risk of CTHD compared to children with the maternal copy of the same allele. The risk of CTHD is less influenced by variants in paternal genes involved in the folate, homocysteine, or transsulfuration pathways than variants in maternal genes in those pathways.

A compromised maternal vitamin D status is associated with congenital heart defects in offspring

BACKGROUND

Interactions between genetic and environmental factors, including modifiable maternal nutrition and lifestyle, play a significant role in the pathogenesis of most congenital heart defects (CHD). The aim of this study was to investigate associations between periconceptional maternal vitamin D status and the prevalence of CHD in offspring.

METHODS

A case-control study was performed in 345 mothers of a child with CHD and 432 mothers of a child without CHD from four tertiary hospitals in the Netherlands between 2003 and 2005. Approximately 15months after pregnancy mothers filled out questionnaires regarding general characteristics and periconceptional lifestyle. Maternal blood was obtained to determine serum 25-hydroxyvitamin D and lipid concentrations. The 25-hydroxyvitamin D concentration was stratified into a deficient <50nmol/l, moderate 50-75nmol/l and adequate >75nmol/l status. Logistic regression was performed to study associations between vitamin D status and CHD risk, adjusted for maternal age, body mass index, ethnicity, smoking and total cholesterol concentration.

RESULTS

Case mothers less often had an adequate vitamin D status compared with controls (27% vs. 38%; p=0.002). The use of multivitamin supplements, ethnicity, season and body mass index were associated with vitamin D concentrations. A moderate (odds ratio 1.58, [95%CI 1.08, 2.32]) and deficient (odds ratio 2.15, [95%CI 1.44-3.19]) vitamin D status were associated with CHD in offspring.

CONCLUSION

A compromised maternal vitamin D status is associated with an approximately two-fold increased prevalence of CHD in offspring. Therefore, improvement of the periconceptional maternal vitamin D status is recommended.

A genetic variant in a homocysteine metabolic gene that increases the risk of congenital cardiac septal defects in Han Chinese populations

Elevated homocysteine levels are known to be a risk factor for congenital cardiac septal defects (CCSDs), but the mechanism underlying this effect is unknown. The genetic variants that were significantly associated with circulating homocysteine concentrations have been systematically identified through the genome-wide association studies of one-carbon core metabolites. To examine the role of the genome-wide significant homocysteine related variants in the occurrence of CCSDs, we investigated the association between these variants and CCSDs in Han Chinese populations. Five variants of the genome-wide significant homocysteine-related genes were selected for analysis in two stages of case-controlled studies with a total of 904 CCSD patients and 997 controls. SYT9 expression was detected in human cardiovascular tissue using qRT-PCR. The intronic variant rs11041321 of the SYT9 gene was associated with an increased risk of developing CCSDs in both the separate and combined case-controlled studies. Combined samples from the two stage cohorts had a significant elevation in CCSD risk for the T allele (OR = 1.43, P = 2.6 × 10^-6 ), CT genotype and TT genotype (CT: OR = 1.30, TT: OR = 2.21; P = 1 × 10^-4 ) compared with the wild-type C allele and CC genotype, respectively. The risky T allele carriers exhibited decreased SYT9 mRNA expression, compared with wild-type C allele carriers. The intronic SYT9 variant rs11041321, which exhibits a significant genome-wide association with circulating homocysteine, was associated with the occurrence of CCSDs. This finding helps to characterize the unexpected role of SYT9 in homocysteine metabolism and the development of CCSDs, which further highlighted the interplay of diet, genetics, and human birth defects. © 2017 IUBMB Life, 69(9):700-705, 2017.

A Genetic Variant in FIGN Gene Reduces the Risk of Congenital Heart Disease in Han Chinese Populations

Congenital heart disease (CHD) is one of the most common birth anomalies worldwide. Folate deficiency is an independent risk factor for CHD. Genome-wide association studies (GWAS) revealed that human folate level could be significantly influenced by fidgetin (FIGN), methylenetetrahydrofolate reductase (MTHFR), prickle homolog 2 (PRICKLE2), synaptotagmin 9 (SYT9), gamma-aminobutyric acid B receptor 2 (GABBR2), and alkaline phosphatase (ALPL) genes. The association between the above-mentioned six variants and CHD was examined in the two independent case-control studies in a total of 868 CHD patients and 931 healthy controls. Our results showed that the G > C (rs2119289) variant in intron 4 of FIGN led to a significant reduction of CHD susceptibility in both the separate and combined case-control studies (allele distribution P < 0.001, genotype distribution P < 0.001). Specifically, by analyzing the combined samples, we observed that the risks of CHD in individuals carrying the heterozygous G/C and homozygous C/C genotypes were reduced by 45% (adjusted OR 0.55, 95% CI 0.47-0.67) and 66% (adjusted OR 0.34, 95% CI 0.23-0.50), respectively, in comparison with individuals carrying the wild-type G/G genotype. Our findings have demonstrated that the C allele of variant rs2119289 of FIGN gene is an important genetic marker for decreased CHD risk. Considering that the rs2119289 of FIGN gene is related to the appropriate folate level, FIGN might play an important role in CHD by upregulating plasma folate concentration during embryo heart development. This work provides a new insight for risk assessment of CHD.

Abnormal Biomarkers of Homocysteine Metabolism in Neonates with Conotruncal Heart Defects

Objectives

The etiology of conotruncal heart defects (CHD) remains unknown; however relation between homocysteine, folate levels, and congenital heart disease was found. With this perspective in mind, the aim of the study was to investigate biomarkers of homosyteine metabolism pathway in mothers and their neonates with CHD.

Material and Methods

Forty-three pairs of mothers and their neonates with CHD and forty pairs of mothers and neonates with nonconotruncal heart defects (non-CHD) were enrolled. The control group (CG) consisted of fifty-nine pairs of mothers and their healthy neonates. For estimating the plasma total homocysteine (tHcy), serum folates, and cobalamin levels, mothers' venous blood samples and umbilical cord blood were taken in all groups.

Results

We observed higher tHcy levels in newborns with CHD in comparison to their mothers and to neonates with non-CHD. Cobalamin levels were significantly lower in neonates with CHD compared to other children. Folates and cobalamin levels were lower in CHD mothers compared to their children.

Conclusions

Elevated homocysteine levels in neonates with CHD and folate metabolism disturbances in their mothers were noticed. The observed differences in homocysteine and cobalamin levels between neonates with CHD suggest the influence of various agents disturbing homocysteine metabolic pathways.

Parental Genetic Variants, MTHFR 677C>T and MTRR 66A>G, Associated Differently with Fetal Congenital Heart Defect

Background

Congenital heart defect (CHD) is one of the most common birth defects in the world. The methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) genes are two of the most important candidate genes for fetal CHD. However, the correlations between the two genes and fetal CHD were inconsistent in various reports. Therefore, this study is aimed to evaluate the parental effects of the two genes on fetal CHD via three genetic polymorphisms, MTHFR 677C>T (rs1801133), MTHFR 1298 A>C (rs1801131), and MTRR 66A>G (rs1801394).

Methods

Parents with pregnancy history of fetal CHD were divided into two subgroups: ventricular septal defect (VSD) (21) and non-VSD groups (78). VSD, non-VSD, and 114 control parents (controls) were analyzed in this study. Genotyping of these genetic polymorphisms was done by sequencing.

Results

The MTHFR 677C>T polymorphism of either mothers or fathers was independently associated with fetal non-VSD (P < 0.05) but not VSD, while the MTRR 66A>G polymorphism was independently associated with fetal VSD (P < 0.05) but not non-VSD. No significance was found for MTHFR 1298A>C polymorphism.

Conclusion

In either maternal or paternal group, the MTHFR 677C>T polymorphism was independently related to fetal non-VSD, while the MTRR 66A>G polymorphism was independently related to fetal VSD.

Maternal and infant genetic variants, maternal periconceptional use of selective serotonin reuptake inhibitors, and risk of congenital heart defects in offspring: population based study

Objective To evaluate whether the association between maternal periconceptional use of selective serotonin reuptake inhibitors (SSRIs) and increased risk of congenital heart defects in offspring is modified by maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways.Design Population based study. DNA from mothers, fathers, and infants was genotyped with an Illumina GoldenGate custom single nucleotide polymorphism panel. A hybrid design based on a log linear model was used to calculate relative risks and Bayesian false discovery probabilities (BFDP) to identify polymorphisms associated with congenital heart defects modified by SSRI use.Data sources Data from the US National Birth Defects Prevention Study on 1180 liveborn infants with congenital heart defects and 1644 controls, born 1997-2008.Main outcome measures Cases included infants with selected congenital heart defects and control infants had no major defects. SSRI use was obtained from telephone interviews with mothers.Results For women who reported taking SSRIs periconceptionally, maternal SHMT1 (rs9909104) GG and AGgenotypes were associated with a 5.9 and 2.4 increased risk of select congenital heart defects in offspring, respectively, versus the AA genotype (BFDP=0.69). Compared with the AA genotype, BHMT (rs492842 and rs542852) GG and AG genotypes were associated with twice the riskof congenital heart defects (BFDP=0.74 and 0.79, respectively). MGST1 (rs2075237) CC and ACgenotypes were associated with an increased risk compared with the GG genotype (8.0 and 2.8, respectively; BFDP=0.79). Single nucleotide polymorphism in infant genes in the folate (MTHFS rs12438477), homocysteine (TRDMT1 rs6602178 and GNMT rs11752813) and transsulfuration (GSTP1 rs7941395 and MGST1 rs7294985) pathways were also associated with an increased risk of congenital heart defects.Conclusions Common maternal or infant genetic variants in folate, homocysteine, or transsulfuration pathways are associated with an increased risk of certain congenital heart defects among children of women taking SSRIs during cardiogenesis.

Genome-wide methylation analysis identifies novel CpG loci for perimembranous ventricular septal defects in human

Aim: Congenital heart diseases are the most common birth defects worldwide and leading cause of infant mortality. The perimembranous ventricular septal defect is most prevalent. Epigenetics may provide an underlying mechanism of the gene–environment interactions involved. Materials & methods: We examined epigenome-wide DNA methylation using the Illumina HumanMethylation450 BeadChip in 84 case children and 196 control children. Results: We identified differential methylation of a CpG locus (cg17001566) within the PRDM16 gene after Bonferroni correction (p = 9.17 × 10-8). This was validated by bisulfite pyrosequencing. PRDM16 functions as a repressor of TGF-β signaling controlling tissue morphogenesis crucial during cardiogenesis. At 15% false-discovery rate, we identified seven additional CpG loci. Conclusion: These findings provide novel insights in the pathogenesis of perimembranous ventricular septal defect, which is of interest for future prediction and prevention.

Maternal exposure to ambient PM2.5 exaggerates fetal cardiovascular maldevelopment induced by homocysteine in rats

Maternal exposure to airborne particulate matter with aerodynamic diameter <2.5 µm (PM_2.5 ) during pregnancy and lactation periods is associated with filial congenital cardiovascular diseases. This study aimed to investigate the toxic effects of maternal exposure to ambient levels of PM_2.5 on filial cardiovascular maldevelopment induced by homocysteine. Using a 2 × 2 factorial design, rats were randomized into four groups and were exposed to ambient PM_2.5 or filtered air (FA) throughout the pregnancy and lactation periods coupled with the administration of either homocysteine (HCY) or normal saline (NS) daily from gestation days 8-10. Morphological changes in the heart, myocardial apoptosis, expressions of cardiac progenitor transcriptional factors, and levels of cytokines were investigated in the offspring. The apoptosis-like changes in the myocardium were seen in the FA plus HCY-treated group and more obviously in the PM_2.5 plus HCY-treated group, which was in accordance with an increased myocardial apoptosis rate in the two groups. PM_2.5 exposure resulted in significantly decreased Nkx2-5 protein level and GATA4 and Nkx2-5 mRNA expressions, and significantly increased TNF-α and IL-1β levels. There were significant interactions between PM_2.5 exposure and HCY-treatment that PM_2.5 exposure reduced Nkx2-5 protein levels and GATA4 and Nkx2-5 mRNA expressions in the HCY-treated groups. These results suggest that maternal exposure to PM_2.5 , even at the ambient levels in urban regions in China, exaggerates filial cardiovascular maldevelopment induced by HCY in a murine model, exacerbating structural abnormalities in the filial cardiac tissue, which is possibly associated with oxidative stress and reduced GATA4 and Nkx2-5 transcription factor expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 877-889, 2017.

An artificial neural network prediction model of congenital heart disease based on risk factors: A hospital-based case-control study

An artificial neural network (ANN) model was developed to predict the risks of congenital heart disease (CHD) in pregnant women.This hospital-based case-control study involved 119 CHD cases and 239 controls all recruited from birth defect surveillance hospitals in Hunan Province between July 2013 and June 2014. All subjects were interviewed face-to-face to fill in a questionnaire that covered 36 CHD-related variables. The 358 subjects were randomly divided into a training set and a testing set at the ratio of 85:15. The training set was used to identify the significant predictors of CHD by univariate logistic regression analyses and develop a standard feed-forward back-propagation neural network (BPNN) model for the prediction of CHD. The testing set was used to test and evaluate the performance of the ANN model. Univariate logistic regression analyses were performed on SPSS 18.0. The ANN models were developed on Matlab 7.1.The univariate logistic regression identified 15 predictors that were significantly associated with CHD, including education level (odds ratio  = 0.55), gravidity (1.95), parity (2.01), history of abnormal reproduction (2.49), family history of CHD (5.23), maternal chronic disease (4.19), maternal upper respiratory tract infection (2.08), environmental pollution around maternal dwelling place (3.63), maternal exposure to occupational hazards (3.53), maternal mental stress (2.48), paternal chronic disease (4.87), paternal exposure to occupational hazards (2.51), intake of vegetable/fruit (0.45), intake of fish/shrimp/meat/egg (0.59), and intake of milk/soymilk (0.55). After many trials, we selected a 3-layer BPNN model with 15, 12, and 1 neuron in the input, hidden, and output layers, respectively, as the best prediction model. The prediction model has accuracies of 0.91 and 0.86 on the training and testing sets, respectively. The sensitivity, specificity, and Yuden Index on the testing set (training set) are 0.78 (0.83), 0.90 (0.95), and 0.68 (0.78), respectively. The areas under the receiver operating curve on the testing and training sets are 0.87 and 0.97, respectively.This study suggests that the BPNN model could be used to predict the risk of CHD in individuals. This model should be further improved by large-sample-size research.

Maternal hyperhomocysteinemia and congenital heart defects: A prospective case control study in Indian population

Objective

Very few studies have been conducted in this part of world to identify relation between maternal serum homocysteine levels and congenital heart disease in their offsprings. With this perspective in mind, this study was carried out.

Methods

Fifty women were enrolled in this study. Thirty of these had delivered neonates who were diagnosed to have congenital heart diseases. These were treated as cases. Twenty of these women had delivered neonates who did not have any congenital heart diseases and were treated as controls. For estimating the levels of plasma homocysteine, fasting blood samples were taken from the women in both groups.

Results

Out of 30 cases, 14 (46.6%) had a tHcy level more than 15 μmol/l and all these women had delivered babies who were found to have congenital heart diseases. Out of controls, only 3 (15%) had a tHcy level more than 15 μmol/l. In babies with ventricular septal defects, the mean maternal plasma tHcy level was 13.30 μmol/l. In babies with Tetralogy of Fallot, the mean maternal plasma tHcy level was 40.07 μmol/l. In babies with Transposition of Great Vessels, the mean maternal plasma tHcy level was 40.93 μmol/l. In babies with Tricuspid atresia, the mean maternal plasma tHcy level was 24.89 μmol/l.

Conclusions

Increased levels of maternal serum homocysteine are associated with increased risk of occurrence of congenital heart defects in their offsprings, suggesting that maternal hyperhomocysteinemia is an independent risk factor for congenital heart defects.

Homocysteine in embryo culture media as a predictor of pregnancy outcome in assisted reproductive technology

The aim of this study was to determine whether homocysteine (hcy) concentrations in embryo culture media correlate with pregnancy outcome in assisted reproductive technology (ART) cycles. Forty patients who underwent single embryo transfer at the infertility clinic of a tertiary care center were recruited for this case-control study. Spent embryo culture media from all patients were collected after single embryo transfer on day 3 (n = 40). Hcy concentrations in embryo culture media were analyzed by enzyme cycling method. Patients were grouped according to the diagnosis of a clinical pregnancy. Sixteen patients were pregnant while 24 patients failed to achieve conception. Mean Hcy levels in the culture media were significantly different between the groups (p < 0.003), as 4.58 ± 1.31 μmol/l in the non-pregnant group and 3.37 ± 0.92 μmol/l in the pregnant group. Receiver operator curve analysis for determining the diagnostic potential of Hcy for pregnancy revealed an area under the curve of 0.792 (confidence interval: 0.65-0.94; p < 0.05). A cut-off value of 3.53 μmol/l was determined with a sensitivity of 83.3%, and a specificity of 68.8%. Lower hcy levels were associated with a better chance of pregnancy and better embryo grades. Hcy may be introduced as an individual metabolomic profiling marker for embryos.

High prevalence of suboptimal vitamin B12 status in young adult women of South Asian and European ethnicity

Suboptimal vitamin B12 (B12) status has been associated with an increased risk of congenital anomalies, preterm birth, and childhood insulin resistance. South Asians – Canada’s largest minority group – and women of reproductive age are vulnerable to B12 deficiency. This study aimed to assess the prevalence of and factors associated with B12 deficiency and suboptimal B12 status in a convenience sample of young adult women of South Asian and European descent in Metro Vancouver. We measured serum B12, holotranscobalamin, plasma methylmalonic acid, red blood cell and plasma folate, and hematologic parameters in 206 nonpregnant, healthy women aged 19–35 years. Categorization for B12 status adhered to serum B12 cutoffs for deficiency (<148 pmol/L) and suboptimal B12 status (148–220 pmol/L). We collected demographic, lifestyle, and dietary intake data and conducted genotyping for common genetic variants linked to B-vitamin metabolism. The prevalence of deficiency and suboptimal B12 status were 14% and 20%, respectively. Serum vitamin B12 concentrations were negatively associated with oral contraceptive use and first-generation immigrant status, and positively with dietary B12 intake and B12 supplement use. The prevalence of B12 inadequacy in this sample of highly educated women is higher than in the general Canadian population. In light of maternal and fetal health risks associated with B12 inadequacy in early-pregnancy, practitioners should consider monitoring B12 status before and during early pregnancy, especially in immigrants and women with low dietary B12 intakes including non-users of vitamin supplements.

Vitamin B-12 and Perinatal Health

Vitamin B-12 deficiency (<148 pmol/L) is associated with adverse maternal and neonatal outcomes, including developmental anomalies, spontaneous abortions, preeclampsia, and low birth weight (<2500 g). The importance of adequate vitamin B-12 status periconceptionally and during pregnancy cannot be overemphasized, given its fundamental role in neural myelination, brain development, and growth. Infants born to vitamin B-12-deficient women may be at increased risk of neural tube closure defects, and maternal vitamin B-12 insufficiency (<200 pmol/L) can impair infant growth, psychomotor function, and brain development, which may be irreversible. However, the underlying causal mechanisms are unknown. This review was conducted to examine the evidence that links maternal vitamin B-12 status and perinatal outcomes. Despite the high prevalence of vitamin B-12 deficiency and associated risk of pregnancy complications, few prospective studies and, to our knowledge, only 1 randomized trial have examined the effects of vitamin B-12 supplementation during pregnancy. The role of vitamin B-12 in the etiology of adverse perinatal outcomes needs to be elucidated to inform public health interventions.

Cardiovascular diseases in grandparents and the risk of congenital heart diseases in grandchildren

Hyperglycemia, dyslipidemia and hyperhomocysteinemia are associated with both adult cardiovascular disease (CVD) and having a child with a congenital heart disease (CHD). We investigated associations between CVD in grandparents and the risk of CHD in grandchildren. In a case-control family study, we obtained detailed questionnaire information on CVD and CHD in 247 families with a CHD child and 203 families without a CHD child. Grandparents with CVD or intermittent claudication (IC) were significantly associated with an increased risk for CHD in grandchildren [OR 1.39 (95% CI 1.03-1.89) and OR 2.77 (95% CI 1.02-7.56), respectively]. The risk of CHD grandchildren was particularly increased in paternal grandfathers with CVD [OR 1.85 (95% CI 1.01-3.37)]. Overall, having a grandparent with CVD increased the risk for CHD in the grandchild by 1.65 (95% CI 1.12-2.41). After adjustment for potential maternal confounders, this risk was 1.44 (95% CI 0.94-2.21). Having two or more grandparents with CVD was associated with an approximately threefold risk for CHD grandchildren [OR adjusted 2.72 (95% CI 1.08-6.89)]. Our data suggest that CVD and IC in grandparents are associated with an increased risk of having a CHD grandchild. These first findings may be explained by shared causality of derangements in metabolic pathways and are in line with the fetal origins of health and disease.

Morphogenesis and molecular considerations on congenital cardiac septal defects

The primary unseptated heart tube undergoes extensive remodeling including septation at the atrial, atrioventricular, ventricular, and ventriculo-arterial level. Alignment and fusion of the septal components is required to ensure full septation of the heart. Deficiencies lead to septal defects at various levels. Addition of myocardium and mesenchymal tissues from the second heart field (SHF) to the primary heart tube, as well as a population of neural crest cells, provides the necessary cellular players. Surprisingly, the study of the molecular background of these defects does not show a great diversity of responsible transcription factors and downstream gene pathways. Epigenetic modulation and mutations high up in several transcription factor pathways (e.g. NODAL and GATA4) may lead to defects at all levels. Disturbance of modulating pathways, involving primarily the SHF-derived cell populations and the genes expressed therein, results at the arterial pole (e.g. TBX1) in a spectrum of ventricular septal defects located at the level of the outflow tract. At the venous pole (e.g. TBX5), it can explain a variety of atrial septal defects. The various defects can occur as isolated anomalies or within families. In this review developmental, morphological, genetic, as well as epigenetic aspects of septal defects are discussed.

Early pregnancy exposure to antihistamines and risk of congenital heart defects: results of two case-control studies

We aimed to study the association between use of antihistamines in early pregnancy and congenital heart defects (CHD) in the offspring.

DESIGN

Two case-control studies.

SETTING

HAVEN study, Erasmus MC, University Medical Centre, Rotterdam, and Eurocat Northern Netherlands (NNL), University Medical Center Groningen, Groningen, the Netherlands. We studied 361 children with CHD and 410 controls without congenital malformations from the HAVEN study and replicated the analyses in 445 children with CHD and 530 controls from the Eurocat NNL registry. Information about antihistamine use in early pregnancy and potential confounders was obtained from questionnaires postpartum. We calculated the association between antihistamines and CHD risk by multivariable logistic regression analysis.

MAIN OUTCOME MEASURES

Odds ratios (OR) with 95% confidence intervals (CI). In the HAVEN study, 25 of 771 mothers used antihistamines that were associated with an increased CHD risk (OR 3.0, 95% CI 1.2-7.3), particularly atrioventricular septal defects (AVSD) (OR 5.1, 95 % CI 1.3-20.5) and perimembranous ventricular septal defects (pVSD) (OR 5.1, 95% CI 1.8-14.4). Mothers with severe nausea who did not use antihistamines had a reduced risk (OR 0.7, 95% CI 0.5-0.98), whereas nauseous mothers using antihistamines showed an almost fivefold increased risk of pVSD (OR 4.8, 95% CI 1.1-21.8). The association between antihistamines and AVSD was confirmed in the Eurocat cohort (OR 3.5, 95% CI 1.4-8.7), but we could not replicate the association with overall CHD risk. We found a positive association between antihistamine use in early pregnancy and CHD risk, particularly AVSD, which seemed to be independent of nausea/vomiting.

Genetic variant in MTRR, but not MTR, is associated with risk of congenital heart disease: an integrated meta-analysis

Background

Congenital heart disease (CHD) is one of the most common birth defects and the leading cause of deaths among individuals with congenital structural abnormalities worldwide. Both Methionine synthase reductase (MTRR) and Methionine synthase (MTR) are key enzymes involved in the metabolic pathway of homocysteine, which are significant in the earlier period embryogenesis, particularly in the cardiac development. Evidence is mounting for the association between MTRR A66G (rs1801394)/MTR A2756G (rs1805087) and the CHD risk, but results are controversial. Therefore, we conducted a meta-analysis integrating case-control and transmitted disequilibrium test (TDT) studies to obtain more precise estimate of the associations of these two variants with the CHD risk.

Methods

To combine case-control and TDT studies, we used the Catmap package of R software to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

A total of 9 reports were included in the final meta-analysis. Eight of them comprised of 914 cases, 964 controls, and 441 families that were germane to MTRR A66G polymorphism; and 4 reports comprised of 250 cases, 205 controls, and 53 families that were relevant to MTR A2756G polymorphism. The pooled OR for the MTRR 66 G allele versus A allele was 1.35 (95% CI = 1.14–1.59, P<0.001, P_{heterogeneity} = 0.073). For MTR A2756G, the G allele conferred a pooled OR of 1.10 (95% CI = 0.78–1.57, P = 0.597, P_{heterogeneity} = 0.173) compared with the A allele. Sensitivity analyses were carried out to asses the effects of each individual study on the pooled OR, indicating the stability of the outcome. Moreover, positive results were also obtained in all subgroups stratified by study type and ethnicity except the subgroup of TDT studies in MTRR A66G variant.

Conclusions

This meta-analysis demonstrated a suggestive result that the A66G variant in MTRR, but not the A2756G in MTR, may be associated with the increase of CHD risks.

A genetic variant in vitamin B12 metabolic genes that reduces the risk of congenital heart disease in Han Chinese populations

BACKGROUND

Genome-wide association studies on components of the one-carbon metabolic pathway revealed that human vitamin B12 levels could be significantly influenced by variations in the fucosyltransferase 2 (FUT2), cubilin (CUBN), and transcobalamin-I (TCN1) genes. An altered vitamin B12 level is an important factor that disturbs the homeostasis of the folate metabolism pathway, which in turn can potentially lead to the development of congenital heart disease (CHD). Therefore, we investigated the association between the variants of vitamin B12-related genes and CHD in Han Chinese populations.

METHODS AND RESULTS

Six variants of the vitamin B12-related genes were selected for analysis in two independent case-control studies, with a total of 868 CHD patients and 931 controls. The variant rs11254363 of the CUBN gene was associated with a decreased risk of developing CHD in both the separate and combined case-control studies. Combined samples from the two cohorts had a significant decrease in CHD risk for the G allele (OR = 0.48, P = 1.7×10⁻⁵) and AG+GG genotypes (OR = 0.49, P = 4×10⁻⁵), compared with the wild-type A allele and AA genotype, respectively.

CONCLUSIONS

Considering the G allele of variant rs11254363 of the CUBN gene was associated with an increased level of circulating vitamin B12. This result suggested that the carriers of the G allele would benefit from the protection offered by the high vitamin B12 concentration during critical heart development stages. This finding shed light on the unexpected role of CUBN in CHD development and highlighted the interplay of diet, genetics, and human birth defects.

Association between 5, 10-methylenetetrahydrofolate reductase (MTHFR) polymorphisms and congenital heart disease: A meta-analysis

Background

Inconsistent results were reported in recent literature regarding the association between methylenetetrahydrofolate reductase (MTHFR) C677T/A1298C polymorphisms and the susceptibility of congenital heart disease (CHD). In this study, we performed a meta-analysis to investigate the associations by employing multiple analytical methods.

Methods

Literature search was performed and published articles were obtained from PubMed, Embase and CNKI databases based on the exclusion and inclusion criteria. Data were extracted from eligible studies and the crude odds ratios and their corresponding 95% confidence intervals (CIs) were calculated using random or fix effects model to evaluate the associations between the MTHFR C677T/A1298C polymorphisms and CHD development. Subgroup based analysis was performed by Hardy–Weinberg equilibrium, ethnicity, types of CHD, source of control and sample size.

Results

Twenty-four eligible studies were included in this meta-analysis. Significant association was found between fetal MTHFR C677T polymorphism and CHD development in all genetic models. The pooled ORs and 95% CIs in all genetic models indicated that MTHFR C677T polymorphism was significantly associated with CHD in Asian, but not Caucasian in subgroup analysis. The maternal MTHFR C677T polymorphism was not associated with CHD except for recessive model. Moreover, neither maternal nor fetal MTHFR A1298C polymorphism was associated with CHD.

Conclusion

The fetal MTHFR C677T polymorphism may increase the susceptibility to CHD. Fetal MTHFR C677T polymorphism was more likely to affect Asian fetus than Caucasian. The MTHFR A1298C polymorphism may not be a risk of congenital heart disease.

Nongenetic risk factors and congenital heart defects

Advances have been made in identifying genetic etiologies of congenital heart defects. Through this knowledge, preventive strategies have been designed and instituted, and prospective parents are counseled regarding their risk of having an affected child. Great strides have been made in genetic variant identification, and genetic susceptibility to environmental exposures has been hypothesized as an etiology for congenital heart defects. Unfortunately, similar advances in understanding have not been made regarding strategies to prevent nongenetic risk factors. Less information is available regarding the potential adverse effect of modifiable risk factors on the fetal heart. This review summarizes the available literature on these modifiable exposures that may alter the risk for congenital heart disease. Information regarding paternal characteristics and conditions, maternal therapeutic drug exposures, parental nontherapeutic drug exposures, and parental environmental exposures are presented. Factors are presented in terms of risk for congenital heart defects as a group. These factors also are broken down by specific defect type. Although additional investigations are needed in this area, many of the discussed risk factors present an opportunity for prevention of potential disease.

Analysis of MTHFR and MTRR Gene Polymorphisms in Iranian Ventricular Septal Defect Subjects

Ventricular septal defect (VSD) is one of the most common types of congenital heart defects (CHD). There are vivid multifactorial causes for VSD in which both genetic and environmental risk factors are consequential in the development of CHD. Methionine synthase reductase (MTRR) and methylenetetrahydrofolate reductase (MTHFR) are two of the key regulatory enzymes involved in the metabolic pathway of homocysteine. Genes involved in homocysteine/folate metabolism may play an important role in CHDs. In this study; we determined the association of A66G and C524T polymorphisms of the MTRR gene and C677T polymorphism of the MTHFR gene in Iranian VSD subjects. A total of 123 children with VSDs and 125 healthy children were included in this study. Genomic DNA was extracted from the buccal cells of all the subjects. The restriction fragment length polymorphism polymerase chain reaction (PCR-RFLP) method was carried out to amplify the A66G and C524T polymorphism of MTRR and C677T polymorphism of MTHFR genes digested with Hinf1, Xho1 and Nde1 enzymes, respectively. The genotype frequencies of CC, CT and TT of MTRR gene among the studied cases were 43.1%, 40.7% and 16.3%, respectively, compared to 52.8%, 43.2% and 4.0%, respectively among the controls. For the MTRR A66G gene polymorphism, the genotypes frequencies of AA, AG and GG among the cases were 33.3%, 43.9% and 22.8%, respectively, while the frequencies were 49.6%, 42.4% and 8.0%, respectively, among control subjects. The frequencies for CC and CT genotypes of the MTHFR gene were 51.2% and 48.8%, respectively, in VSD patients compared to 56.8% and 43.2% respectively, in control subjects. Apart from MTHFR C677T polymorphism, significant differences were noticed (p < 0.05) in C524T and A66G polymorphisms of the MTRR gene between cases and control subjects.

Polymorphism 677C → T MTHFR gene in Mexican mothers of children with complex congenital heart disease

Congenital heart defects (CHD) are the third leading cause of death in children <1 year of age in Mexico where there is a high prevalence of the 677C → T polymorphism of the MTHFR gene. This is important because the homozygous 677T/T MTHFR gene and deficiency of folic acid (FA) intake have been associated with CHD. Our objective was to analyze the possible association between the genotype 677T/T of the MTHFR gene and supplementation of FA in Mexican women with the presence of complex CHD in their children. We analyzed genotypes of 31 mothers of children with complex CHD (group I) and 62 mothers of healthy children (group II) and investigated FA supplementation during pregnancy in both study groups. Allele frequencies in group I were 41.9 % for C and 58.1 % for T and 22.6 % for genotype frequencies CC, 38.7 % for CT, and 38.7 % for TT. Allele frequencies in group II were 63.7 % for C and 36.3 % for T and 38.7 % for genotype frequencies CC, 50 % for CT and 11.3 % for TT. Both populations are in Hardy-Weinberg equilibrium. Odds ratio for having a child with a complex CHD was 5.9, p = 0.008 (95 % CI 1.67; 20.63) for the TT genotype. FA supplementation at any time during pregnancy was 90.3 and 87.9 % in groups II and I respectively (p > 0.05). Association was found between the maternal genotype (677/TT MTHFR) with the presence of complex CHD in their offspring. No differences in FA supplementation during any stage were found between groups.

A derangement of the maternal lipid profile is associated with an elevated risk of congenital heart disease in the offspring

BACKGROUND AND AIMS

Maternal hyperglycaemia and hyperhomocysteinaemia are risk factors for congenital heart disease (CHD). These metabolic derangements and deranged lipid levels are associated with adult cardiovascular disease. We examined whether maternal lipid levels are associated with the risk of CHD offspring.

METHODS AND RESULTS

From 2003 onwards, a case-control study was conducted. Participants were mothers of children with (n = 261) and without (n = 325) CHD. At around 16 months after the index-pregnancy, maternal lipid levels were determined. Maternal characteristics and lipid levels were compared by Student's t-test. In a multivariable logistic regression model, risk estimates were calculated for associations between CHD and lipid levels. Adjustments were made for maternal age, diabetes, ethnicity, body mass index (BMI), parity, periconception folic acid use and total homocysteine levels. Outcome measures are presented in (geometric) means (p5-p95) and odds ratios (ORs) with 95% confidence intervals (CIs). Case mothers showed higher cholesterol (4.9 vs. 4.7 mmol l(-1), P < 0.05), low-density lipoprotein (LDL)-cholesterol (3.2 vs. 3.0 mmol l(-1), P < 0.05), apolipoprotein B (84.0 vs. 80.0 mg dl(-1), P < 0.01) and homocysteine (10.8 vs. 10.2 μmol l(-1), P < 0.05) than controls. LDL-cholesterol above 3.3 mmol l(-1) (OR 1.6 (95%CI, 1.1-2.3)) and apolipoprotein B above 85.0 mg dl(-1) were associated with an almost twofold increased CHD risk (OR 1.8 (95%CI, 1.2-2.6)). This was supported by elevated CHD risks per unit standard deviation increase in cholesterol (OR 1.2 (95% CI 1.03-1.5)), LDL-cholesterol (OR 1.3 (95%CI, 1.1-1.6) and apolipoprotein B (OR 1.3 (95% CI 1.1-1.6)). Apolipoprotein B was most strongly associated with CHD risk.

CONCLUSION

A mildly deranged maternal lipid profile is associated with an increased risk of CHD offspring.

The association between homocysteine in the follicular fluid with embryo quality and pregnancy rate in assisted reproductive techniques

PURPOSE

To investigate the association between follicular fluid homocysteine levels and embryo quality and pregnancy rates in patients undergoing assisted reproduction.

METHODS

Fifty infertile women who were admitted to our clinic were enrolled in the study. Ovulation induction was performed by using GnRH agonist and gonadotropins. For each patient, homocysteine level in the follicular fluid was measured by using nephelometric method after the oocyte pick-up. The association between the homocysteine concentration in the follicular fluid and the oocyte-embryo quality, pregnancy rates and hormone levels were investigated.

RESULTS

Mean ± SD Hcy was 9.6 ± 2.02 μmol/L and 14.9 ± 2.93 μmol/L in pregnant and non-pregnant women, respectively (p < 0.0001). There were no statistically significant differences between pregnant and non-pregnant women in mean age, duration of infertility, body mass index, the oocyte-embryo quality parameters, and hormone levels. Homocystein did not have any correlation with M2, late M2, and total number of oocytes, number of fertilized oocytes and transferred embryos, and embryo quality grade. Area under curve (AUC) of hcy for prediction of pregnancy failure was 0.922 (p = 0.0001, 95% Confidence interval 0.85-0.99). A threshold of 11.9 μmol/L of hcy had a sensitivity of 82%, specificity of 100%, positive predictive value of 100% and negative predictive value of 91.6% for prediction of pregnancy failure. The subgroup analysis in male factor infertility group (n = 28), showed that mean homocystein was 9.9 ± 2.44 μmol/L and 14.1 ± 2.72 μmol/L in pregnant and non-pregnant women, respectively (p = 0.002).

CONCLUSION

Low follicular fluid homocysteine level is associated with a better chance of clinical pregnancy.