Dataset Information

FUT Genotypes, Secretor Status, H.pylori Antibody Levels and Vitamin-B12 Concentrations in Indians

ABSTRACT: Abstract

Objectives

Background: The FUT2 gene is responsible for the secretion of ABO blood type antigens into the body fluids (saliva, mucous, urine, tears, breast milk, sweat, and semen). Those who secrete the antigens into body fluids are call secretors, those who do not are called non-secretors. Hypothesis: GWAS studies have reported FUT gene variants to be associated with circulating vitamin-B12 (Vit-B12) concentrations. Missense mutations in the FUT2 gene result in a non-secretor phenotype. Thus, the secretory status of an individual may affect circulating vitamin-B12 concentrations over and above the genotype.

Methods

Materials and Methods: We included 780 participants (271 children, 282 mothers, and 227 fathers) from Pune Maternal Nutrition Study (PMNS). We measured the secretor status of individuals in saliva by hemagglutination test. A total of eight genetic variants including six SNPs from the FUT2 gene (rs492602, rs681343, rs281377, rs601338, rs1800027, and rs602662) and two SNPs from the FUT6 gene (rs3760776 and rs3760775) from our previous GWAS study were correlated with circulating vitamin-B12 levels. We tested the associations of FUT gene variants with secretor status phenotype and of the secretor phenotype with circulating vit-B12, folate, and ferritin concentrations in addition to H.pylori antibody levels.

Results

Results and Discussion: We found 33% of participants were non-secretors compared to 20% reported in Western Caucasian populations. Non-secretors had higher vitamin-B12 concentrations but not of folate and ferritin, vitamin-B12 associations were over and above FUT genotypes. Non-secretors showed a higher response to Vit-B12 supplementation. We found a FUT2 haplotype () to be strongly associated with Vit-B12 concentrations and non-secretor status. Non-secretors had lower H.pylori antibody concentrations. FUT6 genotype and haplotype were associated with Vit-B12 concentrations but not with secretor status and H.pylori antibody levels.

Conclusions

Our data suggest that secretor status may influence Vit-B12 concentrations through susceptibility to H.pylori infection and possibly other gut microbiota. A higher frequency of non-secretors in Indians could offer a selective advantage against Vit-B12 deficiency.

Funding Sources

BBSRC, UK; MRC, UK; WELLCOME TRUST, UK; DBT, India; ICMR India

SUBMITTER: Sukla K

PROVIDER: S-EPMC8181491 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description: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.