title: Independent associations of polymorphisms in vitamin D binding protein (GC) and vitamin D receptor (VDR) genes with obesity and plasma 25OHD3 levels demonstrate sex dimorphism.
abstract: We investigated a possible association between polymorphisms in vitamin D binding protein (GC) and vitamin D receptor (VDR) genes and obesity in Bahraini adults. For this purpose, 406 subjects with varying body mass indexes (BMIs) were selected. Plasma levels of 25-hydroxyvitamin D3 (25OHD3) were measured by chemiluminescence immunoassay. Six single nucleotide polymorphisms, 2 in the VDR gene (rs731236 TC and rs12721377 AG) and 4 in the GC gene (rs2282679 AC, rs4588 CA, rs7041 GT, and rs2298849 TC), were genotyped by real-time polymerase chain reaction. We found that the rs7041 minor allele (G) and rare genotype (GG) were associated with higher BMI (p = 0.007 and p = 0.012, respectively), but they did not influence 25OHD3 levels. However, the minor alleles of rs2282679 (A) and rs4588 (C) were associated with low 25OHD3 plasma levels (p = 0.039 and p = 0.021, respectively), but not with BMI. Having categorized the subjects based on their sex, we found that (i) rs7041 GG associated with high BMI in females (p = 0.003), (ii) rs4588 CC associated with high BMI in females (p = 0.034) and low 25OHD3 levels in males (p = 0.009), and (iii) rs12721377 AA associated with low 25OHD3 levels in females (p = 0.039). Notably, none of the common haplotypes (6 in the GC gene and 3 in the VDR gene) were associated with BMI. Therefore, polymorphisms in the GC (rs2282679, rs4588, rs7041) and VDR (rs12721377) genes were independently associated with obesity and 25OHD3 levels with a clear sex dimorphism.
authors.affiliation: a Department of Biochemistry, College of Medicine and Medical Sciences (CMMS), Arabian Gulf University (AGU), PO Box 26671, Manama, Bahrain.
authors.forename: Norah
authors.initials: N
authors.lastname: Almesri
authors.affiliation: b Clinical Chemistry Laboratory, Salmaniya Medical Complex (SMC), Manama, Kingdom of Bahrain.
authors.forename: Nagalla S
authors.initials: NS
authors.lastname: Das
authors.affiliation: a Department of Biochemistry, College of Medicine and Medical Sciences (CMMS), Arabian Gulf University (AGU), PO Box 26671, Manama, Bahrain.
authors.forename: Muhallab E
authors.initials: ME
authors.lastname: Ali
authors.affiliation: c Division of Biosciences - Cell and Developmental Biology, University College London (UCL), London, UK.
authors.forename: Khalid
authors.initials: K
authors.lastname: Gumaa
authors.affiliation: a Department of Biochemistry, College of Medicine and Medical Sciences (CMMS), Arabian Gulf University (AGU), PO Box 26671, Manama, Bahrain.
authors.forename: Hayder Ahmed
authors.initials: HA
authors.lastname: Giha
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D044466:Asian People / Q000235:genetics; D001445:Bahrain; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D060005:Genotyping Techniques; D006239:Haplotypes; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D018167:Receptors, Calcitriol / Q000235:genetics* / Q000378:metabolism; D012737:Sex Factors; D014807:Vitamin D / Q000097:blood*; D014809:Vitamin D-Binding Protein / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
chemical_list: D018167:Receptors, Calcitriol; C579457:VDR protein, human; D014809:Vitamin D-Binding Protein; D014807:Vitamin D
keywords: Bahrain; Bahreïn; obesity; obésité; polymorphism; polymorphisme; protéine porteuse de vitamine D; récepteur de vitamine D; vitamin D binding protein; vitamin D receptor