Vitamin B12 Gene Polymorphisms and Chronic Diseases

Das, Debabrata

doi:10.4172/2161-0509.1000149

Cited by 6 publications

(3 citation statements)

References 37 publications

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“…The 776GG homozygous variant encodes a protein that has a lesser affinity for binding vitamin B12 than the wildtype “C” allele [ 22 ]. Additionally, investigations have shown that polymorphisms in the TC protein inhibit the TC-R from recognizing the vitamin B12-TC complex, or diminish the binding of vitamin B12 to TC [ 26 ]. It has been asserted that the growth in obesity is a global problem which will have serious reproductive health consequences.…”

Section: Discussionmentioning

confidence: 99%

Comparison of TCN-2 (776C>G) Gene Polymorphism and Vitamin B12 Status with Different Body Mass Index among Saudi Adults

Ashfaq

Aljaadi

Salaka

et al. 2023

Life

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Background: Overweight and obesity (OO) are significant public health issues, and many elements, including genetics, epigenetics, sedentary lifestyle, comorbid conditions, psychological and environmental pressures, have been linked to OO. More than 2 billion people are presently impacted by the global obesity epidemic, which is still advancing relentlessly. It is a significant public health concern and a major contributor to healthcare costs, because it increases the chance of developing conditions such as heart disease, stroke, type 2 diabetes, and chronic kidney disease (CKD). Using the ranges of 18.5–25 for normality, 25–30 for overweight, and 30 for obesity, BMI (in kg/m2) is used to identify obesity. Vitamin deficiency is one of the causative factors associated with the increasing trend of obesity. Altered vitamin B12 status is a multifactorial trait; changes in B12 status are produced by several single nucleotide polymorphisms (SNPs) in various genes that interact with the environment. They also support coordinated efforts to alter the built environment that is causing the obesity pandemic. Therefore, the present study aimed to evaluate the TCN-2 (776C>G) gene alteration and vitamin B12 levels with respect to different body mass index, as well as associating BMI with other biochemical parameters. Methods: 250 individuals were involved in the study; among them, 100 were in the healthy weight range category (BMI: 18.5 to <25 kg/m2), 100 were overweight (BMI: 25.0 to <30 kg/m2), and 50 were obese (BMI: >30 kg/m2). Participants visited during the screening program were subjected to blood pressure measurement, and further peripheral blood samples were drawn from all the participants in plain as well as in EDTA vials for biochemical (lipid profile and vitamin B12 level) analysis and single nucleotide polymorphism studies. Extracted DNA from whole blood collected in EDTA vials using kit protocol was used for genotyping by PCR-RFLP. Results: The levels of systolic (p < 0.0001) and diastolic blood pressures (p < 0.0001), HDL (p < 0.0001), LDL (p = 0.04), TG (p < 0.0001), cholesterol (p < 0.0001), and VLDL (p < 0.0001) showed significant differences between healthy controls, overweight, and obese groups. The healthy control TCN-2 (776C>G) genotypes were compared with those of overweight and obese participants, and compared to the healthy controls it was observed that overweight (p = 0.01) and obese (p = 0.002) subjects had significant differences in TCN-2 (776C>G) genotypes. For genotypes CG and GG, the odds ratio was 1.61 (0.87–2.95; p = 0.12), and 3.81 (1.47–9.88; p = 0.005) for overweight participants, respectively, and obese participants’ calculated odds ratios were 2.49 (1.16–5.36; p = 0.01) and 5.79 (1.93–17.35; p = 0.001), respectively. The relative risk for genotypes CG and GG, was 1.25 (0.93–1.68; p = 0.12), 2.17 (1.12–4.17; p = 0.02) for overweight participants, while the obese participants’ calculated relative risks were 1.31 (1.03–1.68; p = 0.01) and 2.02 (1.12–3.65; p = 0.001), respectively. Vitamin B12 levels were analyzed, and it was observed that a significant difference existed among overweight (305.5 pmol/L, p < 0.0001) and obese patients (229 pmol/L, p < 0.0001), respectively, as compared to healthy controls (385.5 pmol/L). Correlation analysis showed a significant association of vitamin B12 level with TG, cholesterol and VLDL; it showed a negative correlation, suggesting that decreases in B12 levels may impact the lipid profile. Conclusion: The study concluded that a predisposition to the GG genotype of TCN-2 gene polymorphism (776C>G) may increase susceptibility to obesity and the related complications, and higher odds and relative risk for the GG genotype may increase the risk of having obesity and further related complications. Lower vitamin B12 levels were linked with obesity and overweight, and impaired lipid parameters suggested that lower vitamin B12 may impact the altered lipid profile.

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Section: Discussionmentioning

confidence: 99%

Comparison of TCN-2 (776C>G) Gene Polymorphism and Vitamin B12 Status with Different Body Mass Index among Saudi Adults

Ashfaq

Aljaadi

Salaka

et al. 2023

Life

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“…When there is vitamin B12 deficiency, homocysteine and MMA levels will increase. 12,25,27,28 MTHFR, or methylenetetrahydrofolate reductase, is responsible for folate distribution and increased plasma total homocysteine concentration. [29][30][31] The C665T gene polymorphism causes MTHFR to be thermolabile, decreasing enzyme activity, leading to lower 5-MTHF, vitamin B12, and folate levels, as well as increased homocysteine, and hypomethylation of genomic DNA.…”

Section: Discussionmentioning

confidence: 99%

“…[29][30][31] The C665T gene polymorphism causes MTHFR to be thermolabile, decreasing enzyme activity, leading to lower 5-MTHF, vitamin B12, and folate levels, as well as increased homocysteine, and hypomethylation of genomic DNA. 28,[31][32][33] This implies that hereditary and non-genetic variables affect macrocytic anemia together with other genetic factors such as genes encoding the enzymes methionine synthase (MS)/5-methyltetrahydrofolatehomocysteine methyltransferase (MTR) and methylene-tetrahydrofolate dehydrogenase (MTHFD1), which play roles in homocysteine and folate metabolic pathways, and other physical interactions. 34 In addition, the enzyme cystathionine synthase (CBS), the transcobalamin 2 receptor (TCN2), and methionine synthase reductase, all together affect homocysteine metabolism (MTRR).…”

Section: Discussionmentioning

confidence: 99%

A Case-Control Study of the MTHFR C665T Gene Polymorphism on Macrocytic Anemia Among HIV-Infected Patients Receiving Zidovudine

Pertiwi¹,

Sofro²,

Winarni³

et al. 2022

JMDH

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Background Macrocytic anemia is the most common anemia in HIV-infected patients receiving zidovudine, and is closely related to folate and vitamin B12 deficiencies. Homocysteine >10 μmol/L and increased MMA (methylmalonic acid) levels >24.8 ng/mL indicate high/low folate and vitamin B12 deficiencies. Furthermore, MTHFR (Methylene-tetrahydrofolate-reductase) plays an essential role in the transmethylation of homocysteine to methionine and is related to DNA synthesis. The MTHFR C665T gene polymorphism decreases the activity of MTHFR, which culminates in homocysteinemia. Therefore, this case-control aims to assess the role of the MTHFR C665T gene polymorphism on the risk of macrocytic anemia among HIV-infected individuals receiving zidovudine. Methods This study was conducted using an unmatched case-control design and the participants were HIV-infected adults aged 20 to 59 years old, receiving zidovudine for four weeks and above. A sample of 232 patients was divided into case group with macrocytic anemia and the control having no anemia. Multivariate logistic regression analysis was then implemented to determine the risk factors. Results The results showed that there was a significant difference in the number of female and male patients namely 51.3% and 48.7%, respectively, with p< 0.001. Moreover, the mean age of the cases and control group was 41.9 ± 9.4 and 36.2 ± 8.3. Regarding education, there were significant differences between subjects with low and high education 47.8% vs 52.2% with p<0.001. The majority of patients or 90.95% had taken AZT for more than 6 months. The logistic regression analysis test results showed that sex, age, education level, duration of AZT use, and homocysteine levels were predictors of macrocytic anemia with p<0.05, while MTHFR C665T gene polymorphism and MMA levels were not risk factors. Conclusion MTHFR C665T gene polymorphism does not contribute to the incidence of macrocytic anemia among HIV-infected individuals receiving zidovudine.

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An update on vitamin B12-related gene polymorphisms and B12 status

et al. 2018

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BackgroundVitamin B12 is an essential micronutrient in humans needed for health maintenance. Deficiency of vitamin B12 has been linked to dietary, environmental and genetic factors. Evidence for the genetic basis of vitamin B12 status is poorly understood. However, advancements in genomic techniques have increased the knowledge-base of the genetics of vitamin B12 status. Based on the candidate gene and genome-wide association (GWA) studies, associations between genetic loci in several genes involved in vitamin B12 metabolism have been identified.ObjectiveThe objective of this literature review was to identify and discuss reports of associations between single-nucleotide polymorphisms (SNPs) in vitamin B12 pathway genes and their influence on the circulating levels of vitamin B12.MethodsRelevant articles were obtained through a literature search on PubMed through to May 2017. An article was included if it examined an association of a SNP with serum or plasma vitamin B12 concentration. Beta coefficients and odds ratios were used to describe the strength of an association, and a P < 0.05 was considered as statistically significant. Two reviewers independently evaluated the eligibility for the inclusion criteria and extracted the data.ResultsFrom 23 studies which fulfilled the selection criteria, 16 studies identified SNPs that showed statistically significant associations with vitamin B12 concentrations. Fifty-nine vitamin B12-related gene polymorphisms associated with vitamin B12 status were identified in total, from the following populations: African American, Brazilian, Canadian, Chinese, Danish, English, European ancestry, Icelandic, Indian, Italian, Latino, Northern Irish, Portuguese and residents of the USA.ConclusionOverall, the data analyzed suggests that ethnic-specific associations are involved in the genetic determination of vitamin B12 concentrations. However, despite recent success in genetic studies, the majority of identified genes that could explain variation in vitamin B12 concentrations were from Caucasian populations. Further research utilizing larger sample sizes of non-Caucasian populations is necessary in order to better understand these ethnic-specific associations.

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Vitamin B12 Gene Polymorphisms and Chronic Diseases

Cited by 6 publications

References 37 publications

Comparison of TCN-2 (776C>G) Gene Polymorphism and Vitamin B12 Status with Different Body Mass Index among Saudi Adults

Comparison of TCN-2 (776C>G) Gene Polymorphism and Vitamin B12 Status with Different Body Mass Index among Saudi Adults

A Case-Control Study of the MTHFR C665T Gene Polymorphism on Macrocytic Anemia Among HIV-Infected Patients Receiving Zidovudine

An update on vitamin B12-related gene polymorphisms and B12 status

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