GWAS Identifies Population-specific New Regulatory Variants in FUT6 Associated with Plasma B12 Concentrations in Indians
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Molecular Biology
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Vitamin B12 is an important cofactor in one-carbon metabolism whose dysregulation is associated with various clinical conditions. Indians have a high prevalence of B12 deficiency but little is known about the genetic determinants of circulating B12 concentrations in Indians. We performed a genome-wide association study in 1001 healthy participants in the Pune Maternal Nutrition Study (PMNS), replication studies in 3418 individuals from other Indian cohorts and by meta-analysis identified new variants, rs3760775 (P = 1.2 × 10-23) and rs78060698 (P = 8.3 × 10-17) in FUT6 to be associated with circulating B12 concentrations. Although in-silico analysis replicated both variants in Europeans, differences in the effect allele frequency, effect size and the linkage disequilibrium structure of credible set variants with the reported variants suggest population-specific characteristics in this region. We replicated previously reported variants rs602662, rs601338 in FUT2, rs3760776, rs708686 in FUT6, rs34324219 in TCN1 (all P < 5 × 10-8), rs1131603 in TCN2 (P = 3.4 × 10-5), rs12780845 in CUBN (P = 3.0 × 10-3) and rs2270655 in MMAA (P = 2.0 × 10-3). Circulating B12 concentrations in the PMNS and Parthenon study showed a significant decline with increasing age (P < 0.001), however, the genetic contribution to B12 concentrations remained constant. Luciferase reporter and electrophoretic-mobility shift assay for the FUT6 variant rs78060698 using HepG2 cell line demonstrated strong allele-specific promoter and enhancer activity and differential binding of HNF4α, a key regulator of expression of various fucosyltransferases. Hence, the rs78060698 variant, through regulation of fucosylation may control intestinal host-microbial interaction which could influence B12 concentrations. Our results suggest that in addition to established genetic variants, population-specific variants are important in determining plasma B12 concentrations.
Marphatia A, Wells J, Reid A, Bhalerao A, Yajnik C Front Glob Womens Health. 2025; 5:1174646.
PMID: 39902161 PMC: 11788374. DOI: 10.3389/fgwh.2024.1174646.
Sekar P, Aji A, Ariyasra U, Sari S, Tasrif N, Yani F Nutrients. 2024; 16(17).
PMID: 39275336 PMC: 11397529. DOI: 10.3390/nu16173022.
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Meral G, Aslan E, Tunaligil V, Burkay N, Alper Acar E, Alp M Cureus. 2024; 16(5):e61256.
PMID: 38807972 PMC: 11132663. DOI: 10.7759/cureus.61256.
Yajnik C, Wagh R, Kunte P, Asplund O, Ahlqvist E, Bhat D Lancet Reg Health Southeast Asia. 2023; 14:100182.
PMID: 37492423 PMC: 10363502. DOI: 10.1016/j.lansea.2023.100182.
Packer R, Shrine N, Hall R, Melbourne C, Thompson R, Williams A Eur Respir J. 2023; 61(6).
PMID: 37263751 PMC: 10284065. DOI: 10.1183/13993003.01667-2022.