Association of PPARγ2 gene variant Pro12Ala polymorphism with hypertension and obesity in the aboriginal Qatari population known for being consanguineous

Abdulbari Bener,^1,2 Sarah Darwish,³ Abdulla OAA Al-Hamaq,⁴ Ramzi M Mohammad,^5,6 Mohammad T Yousafzai<sup>1

1</sup>Department of Medical Statistics and Epidemiology, Hamad Medical Corporation, Department of Public Health, Weill Cornell Medical College, Doha, Qatar; ²Department of Evidence for Population Health Unit, School of Epidemiology and Health Sciences, University of Manchester, Manchester, UK; ³Department of Endocrinology, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar; ⁴Qatar Diabetic Associations and Qatar Foundation, Doha, Qatar; ⁵Department of Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University, School of Medicine, MI, USA; ⁶Department of Medicine, Hamad Medical Corporation, Doha, Qatar

Aim: The aim of this study was to investigate the association of the Pro12Ala polymorphism of the human peroxisome proliferator-activated receptor gamma 2 (PPARγ2) gene with hypertension and obesity in a highly consanguineous aboriginal Qatari population.
Design: A cross-sectional survey conducted from January 2011–December 2012.
Setting: Primary health care clinics.
Subjects: A random sample of 1,528 Qatari male and female population older than 20 years of age.
Materials and methods: Data on age, sex, income, level of education, occupation status, body mass index, and blood pressure and lipid profile were obtained. The Pro12Ala in the PPARγ2 gene was detected on the LightCycler^® using two specific probes: (Sensor [G] 5'-CTC CTA TTG ACG CAG AAA GCG-FL and PPAR Anchor 5' LC Red 640- TCC TTC ACT GAT ACA CTG TCT GCA AAC ATA TC-PH). Univariate and multivariate logistic regression were performed.
Result: Out of a total 1,528 participants, 220 were diagnosed with essential hypertension, and 420 were obese. Participants with consanguinity were significantly higher among hypertensive than normotensive (41.9% versus 30.8%; P=0.001). Altogether, more than three-fourths (89%) of the participants had a wild genotype (Pro12Pro), 9.8% were heterozygous with Pro12Ala, and only 1.2% was homozygous with the Ala12Ala genotype. The frequency of the Pro allele was 94.5% in normotensive versus 90.5% in hypertensive, while the distribution of the Ala allele was 5.5% in normotensive versus 9.5% in the hypertensive group (P=0.001). The odds of hypertension were 1.7 times higher among the participants with the Ala allele as compared to those with the Pro, while adjusting for other potential confounders (adjusted odds ratio 1.69; 95% confidence interval 1.12–2.55; P=0.012). There was no association between the PPARγ2Ala allele and obesity (P=0.740).
Conclusion: The current study revealed an association between the PPARγ2Ala allele and hypertension in Qatar's population. On the other hand, this study found no association between the Ala allele and obesity.

Keywords: hypertension, PPARγ2 gene, consanguinity, obesity, Pro12Ala polymorphism