Geographical and ethnic distribution of MTHFR gene polymorphisms and their associations with diseases among Chinese population

The combined effect of MTHFR C677T and A1298C polymorphisms on the risk of digestive system cancer among a hypertensive population

BACKGROUND AND PURPOSE

The enzyme methylenetetrahydrofolate reductase (MTHFR) plays a crucial role in directing folate species towards nucleotide synthesis or DNA methylation. The MTHFR polymorphisms C677T and A1298C have been linked to cancer susceptibility, but the evidence supporting this association has been equivocal. To investigate the individual and joint associations between MTHFR C677T, A1298C, and digestive system cancer in a Chinese hypertensive population, we conducted a population-based case-control study involving 751 digestive system cancer cases and one-to-one matched controls from the China H-type Hypertension Registry Study (CHHRS).

METHODS

We utilized the conditional logistic regression model to evaluate multivariate odds ratios (ORs) and 95% confidence intervals (CIs) of digestive system cancer.

RESULTS

The analysis revealed a significantly lower risk of digestive system cancer in individuals with the CT genotype (adjusted OR: 0.71; 95% CI 0.52, 0.97; P = 0.034) and TT genotype (adjusted OR: 0.57; 95% CI 0.40, 0.82; P = 0.003; P for trend = 0.003) compared to those with the 677CC genotype. Although A1298C did not show a measurable association with digestive system cancer risk, further stratification of 677CT genotype carriers by A1298C homozygotes (AA) and heterozygotes (AC) revealed a distinct trend within these subgroups.

CONCLUSION

These findings indicate a potential protective effect against digestive system cancer associated with the T allele of MTHFR C677T. Moreover, we observed that the presence of different combinations of MTHFR polymorphisms may contribute to varying susceptibilities to digestive system cancer.

Interaction effects of MTHFR C677T and A1298C polymorphisms with maternal glycated haemoglobin levels on adverse birth outcomes

AIMS

The role of maternal genetic factors in the association between high glycated haemoglobin (HbA1c) levels and adverse birth outcomes remains unclear.

MATERIALS AND METHODS

In this study, the maternal HbA1c levels of 5108 normoglycemic pregnant women in China were measured, and A1298C and C677T polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene were genotyped.

RESULTS

Elevated HbA1c levels during the second trimester were associated with increased risks of macrosomia, large-for-gestational age (LGA), preterm birth (PTB), and reduced gestational age (p < 0.05). Pregnant women with MTHFR A1298C AA or C677T CT + TT genotypes were susceptible to adverse pregnancy outcomes related to HbA1c levels. Among pregnant women with the A1298C AA genotype, each standard deviation (SD) increase in HbA1c levels increased the risk of PTB by 1.32-times and reduced the gestational age by 0.11 weeks (p < 0.05). For MTHFR C677T CC + TT genotype carriers, higher HbA1c levels were associated with 1.49-, 1.24-, and 1.23-times increased risks of macrosomia, LGA, and PTB, respectively (p < 0.05). A U-shaped curve for PTB risk in relation to HbA1c levels was observed among the C677T CC + TT participants, with a cut-off value of 4.58%. Among subjects with the A1298C AA genotype combined with the C677T CT + TT genotype, each SD increase in HbA1c levels was associated with 1.40 and 1.37-times increased risks of LGA and PTB, respectively.

CONCLUSIONS

Our findings highlight the importance of glycaemic control during pregnancy and the potential impact of genetic factors on birth outcomes. However, further large-scale studies are required to confirm these findings.

Effects of gene polymorphisms on delayed MTX clearance, toxicity, and metabolomic changes after HD-MTX treatment in children with acute lymphoblastic leukemia

This study aims to assess the role of methotrexate-related gene polymorphisms in children with acute lymphoblastic leukemia (ALL) during high-dose methotrexate (HD-MTX) therapy and to explore their effects on serum metabolites before and after HD-MTX treatment. The MTHFR 677C>T, MTHFR 1298A>C, ABCB1 3435C>T, and GSTP1 313A>G genotypes of 189 children with ALL who received chemotherapy with the CCCG-ALL-2020 regimen from January 2020 to April 2023 were analyzed, and toxic effects were reported according to the Common Terminology Criteria for Adverse Events (CTCAE, version 5.0). Fasting peripheral blood serum samples were collected from 27 children before and after HD-MTX treatment, and plasma metabolites were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS). The results of univariate and multivariate analyses showed that MTHFR 677C>T and ABCB1 3435 C>T gene polymorphisms were associated with the delayed MTX clearance (P < 0.05) and lower platelet count after treatment in children with MTHFR 677 mutation compared with wild-type ones (P < 0.05), and pure mutations in ABCB1 3435 were associated with higher serum creatinine levels (P < 0.05). No significant association was identified between MTHFR 677C>T, MTHFR 1298A>C, ABCB1 3435 C>T, and GSTP1 313A>G genes and hepatotoxicity or nephrotoxicity (P > 0.05). However, the serum metabolomic analysis indicated that the presence of the MTHFR 677C > T gene polymorphism could potentially contribute to delayed MTX clearance by influencing L-phenylalanine metabolism, leading to the occurrence of related toxic side effects.

CONCLUSION

MTHFR 677C>T and ABCB1 3435 C>T predicted the risk of delayed MTX clearance during HD-MTX treatment in children with ALL. Serum L-phenylalanine levels were significantly elevated after HD-MTX treatment in children with the MTHFR 677C>T mutation gene.

TRIAL REGISTRATION

This study was registered at the Chinese Clinical Trial Registry (registration number: ChiCTR2000035264; registration: 2020/08/05; https://www.chictr.org.cn/ ).

WHAT IS KNOWN

• MTX-related genes play an important role in MTX pharmacokinetics and toxicity, but results from different studies are inconsistent and the mechanisms involved are not clear.

WHAT IS NEW

• Characteristics, prognosis, polymorphisms of MTX-related genes, and metabolite changes were comprehensively evaluated in children treated with HD-MTX chemotherapy. • Analysis revealed that both heterozygous and pure mutations in MTHFR 677C>T resulted in a significantly increased risk of delayed MTX clearance, and that L-phenylalanine has the potential to serve as a predictive marker for the metabolic effects of the MTHFR 677C>T polymorphism.

Association of MTHFR 677C>T polymorphism with pregnancy outcomes in IVF/ICSI-ET recipients with adequate synthetic folic acid supplementation

Methylenetetrahydrofolate reductase (MTHFR) genetic polymorphism rs1801133 (677C>T) will decrease the utilization of folate. Folate deficiency and its resulting homocysteine (HCY) accumulation can impair female fertility. Folic acid (FA) supplementation is necessary in pregnant women who are undergoing in-vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) - embryo transfer (ET), and especially in women with MTHFR rs1801133 C-to-T mutations. At present, affordable and accessible synthetic FA is mainly used. However, some studies have suggested that 5-methylenetetrahydrofolate (5-MTHF), a type of active FA, may be more suitable for women with the MTHFR 677C>T polymorphism, since it is safer and more effective. This retrospective study aimed to evaluate whether the MTHFR rs1801133 gene polymorphism is related to the pregnancy outcomes of IVF/ICSI-ET recipients after sufficient supplementation with FA instead of 5-MTHF. Data on 692 women undergoing IVF/ICSI-ET and taking adequate FA were collected. Participant characteristics were compared using the Kruskal-Wallis test and Pearson chi-square test. Logistic regressions were used to calculate the odds ratio (OR) and 95% confidence interval (95% CI), after adjusting for age, BMI, method of fertilization, method of embryo transfer and number of embryos transferred. An additive model (T/T vs. C/C), dominant model (C/T + T/T vs. C/C), and recessive model (T/T vs. C/T + C/C) were evaluated. Analysis revealed that MTHFR rs1801133 in IVF/ICSI-ET women with adequate FA supplementation was not associated with the pregnancy rate but with age (OR = 0.91, 95% CI = 0.88, 0.94, P < 0.001) and BMI (OR = 0.95, 95% CI = 0.90, 0.997, P = 0.037). In 349 clinically pregnant women, no association of the MTHFR 677C>T with pregnancy outcomes was found in the additive model, dominant model, or recessive model. Of the 273 women with positive pregnancy outcomes, 34 had a preterm delivery. MTHFR 677C>T was not associated with a preterm delivery after adjusting for age and BMI. The current results indicated that MTHFR polymorphism rs1801133 was not related to the pregnancy rate or pregnancy outcomes of women undergoing IVF/ICSI-ET with adequate synthetic FA supplementation, suggesting that simple supplementation with less expensive and readily available FA, rather than expensive 5-MTHF, appeared to be appropriate.

[Association between MTHFR gene polymorphism and primary hypertension in children]

OBJECTIVES

To study the distribution characteristics of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism in children with primary hypertension, and to explore the association between MTHFR C677T gene polymorphism and H-type hypertension in children.

METHODS

A total of 121 children with primary hypertension who were hospitalized in the department of cardiovascular medicine from January to July 2021, newly diagnosed, and untreated were retrospectively selected as the subjects. The children were divided into three groups: CC genotype (19 children), CT genotype (51 children), and TT genotype (51 children). According to the serum homocysteine (Hcy) level, they were divided two groups: H-type hypertension (47 children) and simple hypertension (74 children). The medical data were compared between the groups. The association between MTHFR C677T gene polymorphism and H-type hypertension was evaluated.

RESULTS

The mutation frequency of T allele in children with primary hypertension was significantly higher than that in healthy adults in Beijing and Chinese Han adults (P<0.001). The serum Hcy level in the TT genotype group was significantly higher than that in the CC and CT genotype groups (P<0.001). The serum Hcy level in the H-type hypertension group was significantly higher than that in the simple hypertension group (P<0.001), and MTHFR C677T was mostly TT genotype, which was associated with the risk of H-type hypertension (OR=12.71, P<0.001). There was no significant difference in the incidence rate of target organ damage between the H-type hypertension and simple hypertension groups (P>0.05). However, multiple organ involvement was observed in the H-type hypertension group at diagnosis, accounting for 11% (5/47).

CONCLUSIONS

The mutation rate of MTHFR C677T T allele in children with primary hypertension is high and associated with the serum Hcy level. TT genotype is an independent risk factor for H-type hypertension in children, and it may be related to the severity of early target organ damage.

The combination of methylenehydrofolate reductase C677T polymorphism screening and gastrointestinal tumor markers detection may be an early screening method for gastrointestinal cancer related to helicobacter pylori infection

Methyltetrahydrofolate reductase (MTHFR) is a key enzyme in folate metabolism, and its single nucleotide polymorphism (SNP) site C677T may be associated with gastrointestinal cancer. However, the relationship between MTHFR C677T polymorphism and gastrointestinal tumor markers carcinoma embryonic antigen (CEA), carbohydrate antigen 199 (CA199) and carbohydrate antigen 724 (CA724) in Helicobacter pylori (H. pylori) infection is not specified. This study aims to identify the association between MTHFR C677T polymorphism and gastrointestinal tumor markers (CEA, CA199 and CA724) in H. pylori infection. The relationship between MTHFR C677T polymorphism and gastrointestinal tumor markers in 58 patients with H. pylori infection and 94 non-infected patients was studied. We found that TT genotype was a susceptibility factor of H. pylori infection, which was also associated with increased CEA and CA724 levels. Moreover, there was a negative additive interaction between MTHFR gene C677T polymorphism and CEA levels in H.pylori infection. Meanwhile, there were significant differences in CEA levels between MTHFR C677T polymorphism and H.pylori infection. The presence of T allele led to a decrease in CEA levels when ¹³C urea breath test (¹³C-UBT) was positive, while the presence of T allele led to an increase in CEA levels when ¹³C-UBT was negative. Therefore, we suggest that healthy people should take MTHFR C677T polymorphism screening, combined with ¹³C-UBT and gastrointestinal tumor markers detection, which can screen out the susceptible population of H. pylori, and help to detect gastrointestinal cancer in the early stage.

Associations between prenatal exposure to cadmium and lead with neural tube defect risks are modified by single-nucleotide polymorphisms of fetal MTHFR and SOD2: a case-control study

BACKGROUND

Prenatal exposure to heavy metals is implicated in the etiology of birth defects. We investigated whether concentrations of cadmium (Cd) and lead (Pb) in umbilical cord tissue are associated with risk for neural tube defects (NTDs) and whether selected genetic variants of the fetus modify their associations.

METHODS

This study included 166 cases of NTD fetuses/newborns and 166 newborns without congenital malformations. Umbilical cord tissue was collected at birth or elective pregnancy termination. Cd and Pb concentrations were assessed by inductively coupled plasma-mass spectrometry, and 20 single-nucleotide polymorphisms (SNPs) in 9 genes were genotyped. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the risk for NTDs in association with metal concentrations or genotype using logistic regression. Multiplicative-scale interactions between the metals and genotypes on NTD risk were assessed with logistic regression, and additive-scale interactions were estimated with a non-linear mixed effects model.

RESULTS

Higher concentrations of Cd were observed in the NTD group than in the control group, but no difference was found for Pb. Concentrations of Cd above the median level showed a risk effect, while the association between Pb and NTD risk was not significant in univariate analyses. The association of Cd was attenuated after adjusting for periconceptional folic acid supplementation. Fetuses with the AG and GG genotypes of rs4880 in SOD2 (superoxide dismutase 2) tended to have a lower risk, but fetuses with the CT and TT genotypes of rs1801133 in MTHFR (5,10-methylenetetrahydrofolatereductase) have a higher risk for NTDs when compared to their respective wild-type. rs4880 and Cd exhibited a multiplicative-scale interaction on NTD risk: the association between higher Cd and the risk for NTDs was increased by over fourfold in fetuses carrying the G allele [OR 4.43 (1.30-15.07)] compared to fetuses with the wild-type genotype. rs1801133 and Cd exposure showed an additive interaction, with a significant relative excess risk of interaction [RERI 0.64 (0.02-1.25)].

CONCLUSIONS

Prenatal exposure to Cd may be a risk factor for NTDs, and the risk effect may be enhanced in fetuses who carry the G allele of rs4880 in SOD2 and T allele of rs1801133 in MTHFR.

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.

Maternal folic acid supplementation mediates the associations between maternal socioeconomic status and congenital heart diseases in offspring

Low maternal socioeconomic status (SES) is considered as a risk factor of congenital heart diseases (CHDs) in offspring. However, the pathways underpinning the SES-CHDs associations are unclear. We assessed if first trimester maternal folic acid supplementation (FAS) is a mediator of the SES-CHDs associations. This case-control study included 8379 CHD cases and 6918 CHD-free controls from 40 participating centers in Guangdong, Southern China, 2004-2016. All fetuses were screened for CHDs using ultrasound and cases were confirmed by echocardiogram. We collected SES and FAS information during face-to-face interview by obstetricians using a structured questionnaire. Low SES was defined as education attainment <12 years, household individual income <3000 Chinese Yuan/person/month or unemployment. FAS referred to at least 0.4 mg of daily folic acid intake over 5 days/week continuously. We used causal mediation analysis to estimate the direct, indirect and proportion mediated by FAS on the SES-CHDs associations adjusted for confounders. Both low maternal income and education were significantly associated with increased risks of CHDs and lower prevalence of FAS. Low maternal FAS prevalence mediated 10% [95%CI:5%,13%] and 3% [95%CI:1%,5%] of the maternal low income-CHDs and the maternal low education-CHDs associations, respectively. In addition, FAS mediated the highest proportion of the associations between income and multiple critical CHDs [46.9%, 95%CI:24.7%,77%] and conotruncal defects [31.5%, 95%CI:17.1%,52.0%], respectively. Maternal FAS partially mediated the SES-CHDs associations, especially among the most critical and common CHDs. Promoting FAS in low SES women of childbearing age may be a feasible intervention to help prevent CHDs.

Chronic Low-Dose Exposure to Xenoestrogen Ambient Air Pollutants and Breast Cancer Risk: XENAIR Protocol for a Case-Control Study Nested Within the French E3N Cohort

Background

Breast cancer is the most frequent cancer in women in industrialized countries. Lifestyle and environmental factors, particularly endocrine-disrupting pollutants, have been suggested to play a role in breast cancer risk. Current epidemiological studies, although not fully consistent, suggest a positive association of breast cancer risk with exposure to several International Agency for Research on Cancer Group 1 air-pollutant carcinogens, such as particulate matter, polychlorinated biphenyls (PCB), dioxins, Benzo[a]pyrene (BaP), and cadmium. However, epidemiological studies remain scarce and inconsistent. It has been proposed that the menopausal status could modify the relationship between pollutants and breast cancer and that the association varies with hormone receptor status.

Objective

The XENAIR project will investigate the association of breast cancer risk (overall and by hormone receptor status) with chronic exposure to selected air pollutants, including particulate matter, nitrogen dioxide (NO2), ozone (O3), BaP, dioxins, PCB-153, and cadmium.

Methods

Our research is based on a case-control study nested within the French national E3N cohort of 5222 invasive breast cancer cases identified during follow-up from 1990 to 2011, and 5222 matched controls. A questionnaire was sent to all participants to collect their lifetime residential addresses and information on indoor pollution. We will assess these exposures using complementary models of land-use regression, atmospheric dispersion, and regional chemistry-transport (CHIMERE) models, via a Geographic Information System. Associations with breast cancer risk will be modeled using conditional logistic regression models. We will also study the impact of exposure on DNA methylation and interactions with genetic polymorphisms. Appropriate statistical methods, including Bayesian modeling, principal component analysis, and cluster analysis, will be used to assess the impact of multipollutant exposure. The fraction of breast cancer cases attributable to air pollution will be estimated.

Results

The XENAIR project will contribute to current knowledge on the health effects of air pollution and identify and understand environmental modifiable risk factors related to breast cancer risk.

Conclusions

The results will provide relevant evidence to governments and policy-makers to improve effective public health prevention strategies on air pollution. The XENAIR dataset can be used in future efforts to study the effects of exposure to air pollution associated with other chronic conditions.

International Registered Report Identifier (IRRID)

DERR1-10.2196/15167

May the morphological findings in the first-trimester abortion materials be indicative of inherited thrombophilia?

PURPOSE

İnherited thrombophilia is associated with severe pregnancy complications including recurrent spontaneous abortion. In the light of this strong association, the impact of thrombophilic mutations on the placenta and their morphological reflections has aroused attention of both clinicians and pathologists. In the present study, we aimed to show the association between placental abnormalities with thrombophilia by examining the morphological findings in a wide range of first-trimester chorionic villi.

METHODS

We performed a histological examination on the abortion specimens obtained from 129 patients with recurrent pregnancy losses that were evaluated with respect to inherited thrombophilia based on the presence of Factor V Leiden (G1691A), Prothrombin G20210A and methylenetetrahydrofolate reductase (MTHFR) C677T gene mutations detected by genetic analysis. Abortion materials either with and without thrombophilia were evaluated in terms of the morphological parameters such as hydropic change, vascularity, fibrosis, fibrinoid degeneration, Hofbauer macrophage, syncytiotrophoblast knotting, villitis, calcification, villous contour and villous size, hemorrhage, thrombus, proliferation of trophoblasts, villous stromal or villous vascular karyorrhexis.

RESULTS

No statistically significant difference was found between the patient groups with and without thrombophilia in terms of morphological findings except vascularity of chorionic villi. The avascular chorionic villi (<3 vessels per villus) were found in 62.9% and 16.9% obtained from the women with and without thrombophilic mutation, respectively. This difference was statistically significant (P < 0.001).

CONCLUSION

As a conclusion, it could be stated that the analysis of morphological findings in the abortion specimen is not a time-wasting process. Particularly, data related with vascularity of chorionic villi would be precious and beneficial. We suggest that highlighting the presence of avascular villi in the pathology report as a parameter would be guiding for clinicians regarding the impact of the thrombophilic gene mutations.

Association of MTHFR C677T polymorphism with severity and localization of chronic atrophic gastritis patients without Helicobacter pylori infection: a case control study

Background

Previous reports indicate that the methylenetetrahydrofolate reductase (MTHFR) 677C > T polymorphism plays a role in gastric cancer. However, whether it influences the development and progression of atrophic gastritis remains ambiguous. We aimed to determine the possible relationship between MTHFR C677T polymorphism and the severity of atrophic gastritis.

Methods

A total of 128 patients without Helicobacter pylori infection were included in the study. The severity of gastric atrophy was assessed by pathological diagnosis using OLGA and OLGIM Gastritis Staging System. MTHFR 677C > T genotyping was performed by digital fluorescence molecular hybridization. Categorical variables were analyzed by percentages using the χ² test.

Results

In this study, the TT genotype was significantly more frequent among Helicobacter pylori-negative patients aged ≤44 years (age ≤ 44 years vs. > 44 years, P = 0.039). Patients with TT genotype showed a higher ratio of incisura with atrophy or intestinal metaplasia (TT vs. CC + CT, P = 0.02). Furthermore, TT genotype was associated with more severe lesions compared with the CC + CT genotypes (TT vs. CC + CT for atrophy: P = 0.07; for intestinal metaplasia: P = 0.01; for moderate-to-severe lesions: P = 0.01). OLGA and OLGIM stages III-IV were observed more frequently in patients with TT genotype compared with CC + CT genotypes (for OLGA: P = 0.003; for OLGIM: P = 0.036).

Conclusions

The MTHFR 677C > T TT genotype showed an increased risk of moderate-to-severe lesions by OLGA and OLGIM stages, and these results indicate that MTHFR C677T polymorphism may act as a predictive marker for precancerous gastric lesions, especially in Helicobacter pylori-negative patients aged ≤44 years.

Expression of the C677T Polymorphism of the 5, 10-Methylenetetrahydrofolate Reductase (MTHFR) Gene in Patients with Carotid Artery Atherosclerosis

Background

The C677T polymorphism of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism has been associated with hypertension and coronary heart disease, but its relationship with carotid artery remains unknown. This study aimed to investigate the association between the C677T polymorphism of the MTHFR gene in patients with confirmed carotid artery atherosclerosis.

Material/Methods

This retrospective study included 210 patients with carotid artery atherosclerosis (the patient group) and 210 controls (the control group). Color Doppler ultrasound was used to identify carotid artery intimo-medial thickness and atherosclerotic plaques. Sanger sequencing using the polymerase chain reaction (PCR) was used to detect the MTHFR C677T gene polymorphism. Systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting plasma glucose (FPG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), glycosylated hemoglobin (HbA1c), and other laboratory indicators were measured.

Results

SBP, DBP, FPG, TC, LDL-C, HbA1c, and intimo-medial thickness were significantly increased in the patient group compared with the control group, and HDL-C was significantly lower. The allele frequencies of the C667T locus of MTHFR gene were significantly different between the two groups (P<0.05), and the TT genotype and the T allele frequencies in the patient group were higher than in the control group. Logistic regression analysis showed that SBP, TC, LDL-C, and the C667T MTHFR gene polymorphism were risk factors for carotid artery atherosclerosis.

Conclusions

The C677T polymorphism of the MTHFR gene was expressed in patients with carotid artery atherosclerosis.

First-Trimester Maternal Folic Acid Supplementation Reduced Risks of Severe and Most Congenital Heart Diseases in Offspring: A Large Case-Control Study

Background Maternal folic acid supplementation (FAS) reduces the risk of neural tube defects in offspring. However, its effect on congenital heart disease (CHDs), especially on the severe ones remains uncertain. This study aimed to assess the individual and joint effect of first-trimester maternal FAS and multivitamin use on CHDs in offspring. Methods and Results This is a case-control study including 8379 confirmed CHD cases and 6918 controls from 40 healthcare centers of 21 cities in Guangdong Province, China. Adjusted odds ratios (aORs) of FAS and multivitamin use between CHD cases (overall and specific CHD phenotypes) and controls were calculated by controlling for parental confounders. The multiplicative interaction effect of FAS and multivitamin use on CHDs was estimated. A significantly protective association was detected between first-trimester maternal FAS and CHDs among offspring (aOR, 0.69; 95% CI, 0.62-0.76), but not for multivitamin use alone (aOR, 1.42; 95% CI, 0.73-2.78). There was no interaction between FAS and multivitamin use on CHDs (P=0.292). Most CHD phenotypes benefited from FAS (aORs ranged from 0.03-0.85), especially the most severe categories (ie, multiple critical CHDs [aOR, 0.16; 95% CI, 0.12-0.22]) and phenotypes (ie, single ventricle [aOR, 0.03; 95% CI, 0.004-0.21]). Conclusions First-trimester maternal FAS, but not multivitamin use, was substantially associated with lower risk of CHDs, and the association was strongest for the most severe CHD phenotypes. We recommend that women of childbearing age should supplement with folic acid as early as possible, ensuring coverage of the critical window for fetal heart development to prevent CHDs.

Association of antenatal vitamin B complex supplementation with neonatal vitamin B12 status: evidence from a cluster randomized controlled trial

PURPOSE

Evidence about the effect of maternal vitamin B₁₂ supplementation on offspring's vitamin B₁₂ status is limited. The present interventional study sought to evaluate the association of antenatal vitamin B complex supplementation with neonatal vitamin B₁₂ status.

METHODS

In an ongoing cluster randomized controlled trial conducted in three rural counties in northwest China, pregnant women < 20 weeks of gestation were randomized to three treatment groups: blank control, iron supplements, or vitamin B complex supplements. All women were administered folic acid supplements during the periconceptional period. In a sub-study, we collected cord blood samples of 331 participants from the control or vitamin B complex groups in the Xunyi county from January 2017 to December 2017. Plasma concentrations of folate, vitamin B₁₂, and homocysteine were measured. Linear mixed models with a random intercept for cluster were used to compare biochemical indexes between groups after controlling for covariates.

RESULTS

Compared with newborns whose mothers were in the control group, newborns of the vitamin B complex-supplemented women had significantly higher cord plasma vitamin B₁₂ (P = 0.001) and lower homocysteine concentrations (P = 0.043). The association of antenatal vitamin B complex supplementation with cord blood vitamin B₁₂ concentrations appeared to be more pronounced among newborns with high folate status than those with low folate status (P_interaction = 0.060).

CONCLUSIONS

Maternal vitamin B complex supplementation during pregnancy was associated with better neonatal vitamin B₁₂ status in rural northwest China.

Whole Genome Analyses of Chinese Population and De Novo Assembly of A Northern Han Genome

To unravel the genetic mechanisms of disease and physiological traits, it requires comprehensive sequencing analysis of large sample size in Chinese populations. Here, we report the primary results of the Chinese Academy of Sciences Precision Medicine Initiative (CASPMI) project launched by the Chinese Academy of Sciences, including the de novo assembly of a northern Han reference genome (NH1.0) and whole genome analyses of 597 healthy people coming from most areas in China. Given the two existing reference genomes for Han Chinese (YH and HX1) were both from the south, we constructed NH1.0, a new reference genome from a northern individual, by combining the sequencing strategies of PacBio, 10× Genomics, and Bionano mapping. Using this integrated approach, we obtained an N50 scaffold size of 46.63 Mb for the NH1.0 genome and performed a comparative genome analysis of NH1.0 with YH and HX1. In order to generate a genomic variation map of Chinese populations, we performed the whole-genome sequencing of 597 participants and identified 24.85 million (M) single nucleotide variants (SNVs), 3.85 M small indels, and 106,382 structural variations. In the association analysis with collected phenotypes, we found that the T allele of rs1549293 in KAT8 significantly correlated with the waist circumference in northern Han males. Moreover, significant genetic diversity in MTHFR, TCN2, FADS1, and FADS2, which associate with circulating folate, vitamin B12, or lipid metabolism, was observed between northerners and southerners. Especially, for the homocysteine-increasing allele of rs1801133 (MTHFR 677T), we hypothesize that there exists a "comfort" zone for a high frequency of 677T between latitudes of 35-45 degree North. Taken together, our results provide a high-quality northern Han reference genome and novel population-specific data sets of genetic variants for use in the personalized and precision medicine.

Association between homocysteine and multivascular atherosclerosis in stroke-related vascular beds determined by three-dimensional magnetic resonance vessel wall imaging

BACKGROUND

Atherosclerosis in stroke-related vascular beds is the major cause of stroke. Studies demonstrated that multivascular atherosclerosis is prevalent in stroke patients and those with multivascular plaques had higher risk of recurrent stroke.

OBJECTIVES

This study investigated the relationship between homocysteine and multivascular atherosclerosis in stroke-related vascular beds using magnetic resonance imaging.

METHODS

Patients with recent ischemic cerebrovascular symptoms were enrolled and underwent three-dimensional magnetic resonance vessel wall imaging for intracranial arteries, extracranial carotid arteries and aortic arch. Traditional risk factors and homocysteine were measured. Presence of multivascular plaques defined as plaques in at least two stroke-related vascular beds on magnetic resonance imaging was determined. The relationship between homocysteine and characteristics of multivascular plaques was determined.

RESULTS

Of 49 enrolled patients (mean age: 56.3 ± 13.8 years; 35 males), 23 had multivascular plaques. Homocysteine (odds ratio, 1.17; 95% confidence interval, 1.02-1.34; p = 0.022) and age (odds ratio, 1.71; 95% confidence interval, 1.22-2.41; p = 0.002) were significantly associated with presence of multivascular plaques. The adjusted associations remained significant (both p < 0.05). In discriminating presence of multivascular plaques, the area-under-the-curve of age, homocysteine and combination of them was 0.79, 0.70 and 0.87 respectively.

CONCLUSIONS

Homocysteine is independently associated with stroke-related multivascular plaques and combination of age and homocysteine has stronger predictive value.

Association Study of Polymorphisms in Genes Relevant to Vitamin B12 and Folate Metabolism with Childhood Autism Spectrum Disorder in a Han Chinese Population

Background

Both genetic and environmental factors play a role in the development of autism spectrum disorder (ASD). This case-control study examined the association between childhood ASD and single-nucleotide polymorphisms (SNPs) in genes involved with vitamin B12 and folate metabolism.

Material/Methods

Genotypes of transcobalamin 2 (TCN2) rs1801198, methionine synthase (MTR) rs1805087, methionine synthase reductase (MTRR) rs1801394, and methylene tetrahydrofolate reductase (MTHFR) rs1801133 were examined in 201 children with ASD and 200 healthy controls from the Han Chinese population.

Results

Our results showed no association of all examined SNPs with childhood ASD and its severity.

Conclusions

None of the examined SNPs were a risk factor for the susceptibility to childhood ASD and severity of the disease in a Han Chinese population.

Effect of MTHFR A1298C and MTRR A66G Genetic Mutations on Homocysteine Levels in the Chinese Population: A Systematic Review and Meta-analysis

Background and Objectives

The Chinese population typically has inadequate folate intake and no mandatory folic acid fortification. Methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) are the two key regulatory enzymes in the folate/homocysteine (Hcy) metabolism. Hcy has been implicated in the pathogenesis of cardiovascular disease. We conducted a meta-analysis to assess whether the MTHFR gene A1298C and the MTRR gene A66G polymorphisms affect Hcy levels in the Chinese population.

Methods

This analysis included 13 studies with Hcy levels reported as one of the study measurements. Summary estimates of weighted mean differences and 95% confidence intervals (CIs) were obtained using random-effect models.

Results

Overall, there were no significant differences in Hcy concentrations between participants with the MTHFR 1298 CC (12 trials, n = 129), AA (n = 2166; β, -0.51 μmol/L; 95%CI: -2.14, 1.11; P = 0.53), or AC genotype (n = 958; β, 0.55 μmol/L; 95%CI: -0.72, 1.82; P = 0.40). Consistently, compared to those with the MTRR 66 GG genotype (6 trials, n = 156), similar Hcy concentrations were found in participants with the AA (n = 832; β, -0.43 μmol/L; 95%CI: -1.04, 0.17; P = 0.16) or AG (n =743; β, -0.57 μmol/L; 95%CI: -1.46, 0.31; P = 0.21) genotype. Similar results were observed for the dominant and recessive models.

Conclusions

Neither the MTHFR A1298C polymorphism nor the MTRR A66G polymorphism affects Hcy levels in the Chinese population.

Neck circumference associated with arterial blood pressures and hypertension: A cross-sectional community-based study in northern Han Chinese

Although several studies have investigated the associations of neck circumference (NC) with arterial blood pressures (BPs) and hypertension, no such studies have been conducted among Northern Chinese population. Between April and June 2015, a total of 2631 subjects aged ≥35 years old were recruited from Northeastern China. NC and arterial BPs were measured by trained personnel. Generalized linear and logistic regression analyses were applied to examine the associations of NC with arterial BPs and hypertension risk. The optimal cut-off points of NC for predicting hypertension were assessed by the receiver operating characteristic analysis. We found that NC was significantly associated with arterial BPs and hypertension risk in the Northeastern Chinese adults, even after adjusting for many covariates including body mass index, waist circumference or waist-to-hip ratio. The optimal cut-off values for NC to predict hypertension differed with sex, age, and body mass index. Our study suggests that NC may play an independent role in predicting hypertension beyond the classical anthropometric indices, and that it could be used as a valuable anthropometric measurement for routine assessment in primary care clinics and future epidemiological studies.