Genetic variations of vitamin D receptor gene in metabolic syndrome and related diseases in the Thai population.

BACKGROUND AND OBJECTIVES: The genetic variations of vitamin D receptor (VDR) have revealed its association with the risk of metabolic syndrome (MetS). In Thailand, evidence of this association has not been obtained. Thus, this study aimed to investigate the association of VDR gene polymorphism with MetS and related diseases as well as the possible linkage disequilibrium (LD) and haplotypes of VDR in Thai adults. METHODS AND STUDY DESIGN: Four single nucleotide polymorphisms (SNPs) of VDR gene, rs2228570, rs1544410, rs7975232 and rs731236, were genotyped using PCR-RFLP method in 259 MetS and 261 control groups. RESULTS: Genotypes AA of rs1544410, TG of rs7975232 and TG+TT of rs7975232 were significantly associated with an increased risk of MetS [OR 10.8 (2.07-56.1), p=0.005], [OR 1.83 (1.16-2.87), p=0.009] and [OR 1.78 (1.17-2.72), p=0.007], respectively, using GG as a reference. Moreover, genotype AA of rs1544410 showed a strong association compared with GG+AG [OR 11.4 (2.20-59.2), p=0.004]. Diseases related to MetS also had significant associations with two SNPs of the VDR gene (rs1544410 and rs7975232). In addition, LD among rs1544410, rs7975232 and rs731236 was detected. Haplotype CATT significantly increased the risk of MetS [OR 4.32 (1.32- 14.1), p=0.016], although haplotype TGGT reduced the risk [OR 0.68 (0.48-0.98), p=0.042]. CONCLUSIONS: The SNPs rs1544410 and rs7975232 were mainly implicated in the increased risk of MetS in the Thai population. LD and haplotypes of VDR gene related to MetS were also discovered. These SNPs of VDR gene are remarkable genetic factors involved in the development of MetS.

Vitamin D-binding protein and its polymorphisms as a predictor for metabolic syndrome.

AIM: To investigate the relationship of vitamin D-binding protein (GC) and genetic variation of GC (rs4588, rs7041 and rs2282679) with metabolic syndrome (MetS) in the Thai population. MATERIALS & METHODS: GC-globulin concentrations were measured by quantitative western blot analysis in 401 adults. All participants were genotyped using TaqMan allelic discrimination assays. RESULTS: GC-globulin levels were significatly lower in MetS subjects than in control subjects, in which significant negative correlations of GC-globulin levels with systolic blood pressure, glucose and age were found. Male participants who carried the GT genotype for rs4588 showed an increased risk of MetS compared with the GG wild-type (odds ratio: 3.25; p = 0.004). CONCLUSION: GC-globulin concentrations and variation in GC rs4588 were supported as a risk factor for MetS in Thais.