title: Rare mutations of peroxisome proliferator-activated receptor gamma: frequencies and relationship with insulin resistance and diabetes risk in the mixed ancestry population from South Africa.
abstract: Background. Genetic variants in the nuclear transcription receptor, PPARG, are associated with cardiometabolic traits, but reports remain conflicting. We determined the frequency and the clinical relevance of PPARG SNPs in an African mixed ancestry population. Methods. In a cross-sectional study, 820 participants were genotyped for rs1800571, rs72551362, rs72551363, rs72551364, and rs3856806, using allele-specific TaqMan technology. The homeostatic model assessment of insulin (HOMA-IR), β-cells function (HOMA-B%), fasting insulin resistance index (FIRI), and the quantitative insulin-sensitivity check index (QUICKI) were calculated. Results. No sequence variants were found except for the rs3856806. The frequency of the PPARG-His447His variant was 23.8% in the overall population group, with no difference by diabetes status (P = 0.215). The His447His allele T was associated with none of the markers of insulin resistance overall and by diabetes status. In models adjusted for 2-hour insulin, the T allele was associated with lower prevalent diabetes risk (odds ratio 0.56 (95% CI 0.31-0.95)). Conclusion. Our study confirms the almost zero occurrences of known rare PPARG SNPs and has shown for the first time in an African population that one of the common SNPs, His447His, may be protective against type 2 diabetes.
authors.affiliation: Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, P.O. Box 1906, Bellville, Cape Town 7530, South Africa ; Division of Chemical Pathology, Stellenbosch University, Cape Town 7505, South Africa.
authors.forename: Z
authors.initials: Z
authors.lastname: Vergotine
authors.affiliation: Non-Communicable Diseases Research Unit, South African Medical Research Council and University of Cape Town, Cape Town 7505, South Africa.
authors.forename: A P
authors.initials: AP
authors.lastname: Kengne
authors.affiliation: Division of Chemical Pathology, Stellenbosch University, Cape Town 7505, South Africa.
authors.forename: R T
authors.initials: RT
authors.lastname: Erasmus
authors.affiliation: Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, P.O. Box 1906, Bellville, Cape Town 7530, South Africa.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Yako
authors.affiliation: Biomedical Sciences, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, P.O. Box 1906, Bellville, Cape Town 7530, South Africa.
authors.forename: T E
authors.initials: TE
authors.lastname: Matsha