Association of Angiotensin Converting Enzyme Insertion-Deletion Polymorphism with Hypertension in Emiratis with Type 2 Diabetes Mellitus and Its Interaction with Obesity Status.

The association of Angiotensin Converting Enzyme (ACE) insertion-deletion (I/D) polymorphism with Type 2 Diabetes Mellitus (T2DM) and hypertension has been extensively studied throughout various ethnic populations but largely with inconsistent findings. We investigated these associations in Emirati population and their interaction with obesity status. Saliva samples were collected from a total of 564 Emiratis (277 T2DM and 297 healthy). DNA was extracted and the samples were genotyped for ACE I/D polymorphism by a PCR based method followed by gel electrophoresis. Upon evaluation of the ACE I/D polymorphism amongst all T2DM, hypertensive patients, and respective controls regardless of obesity status, ACE DD genotype was not found to be associated with either T2DM [odds ratio (OR) = 1.34, p = 0.086] or hypertension [odd ratio (OR) = 1.02, p = 0.93]. When the genetic variants amongst the nonobese and obese population were analyzed separately, the risk genotype ACE DD conferred significantly increased risk of hypertension in nonobese population [odds ratio (OR) = 1.80, p = 0.02] but was found to be protective against the hypertension in the obese group ((OR) = 0.54, p = 0.01). However, there was no effect of obesity status on the association of ACE genotypes with T2DM. The risk of hypertension associated with ACE DD is modulated by obesity status and hence future genetic association studies should take obesity into account for the interpretation of data. We also confirmed that ACE I/D polymorphism is not associated with T2DM risk in Emirati population.

Association of the Genetic Polymorphisms in Transcription Factor 7-Like 2 and Peroxisome Proliferator-Activated Receptors- γ 2 with Type 2 Diabetes Mellitus and is Interaction with Obesity Status in Emirati Population.

BACKGROUND: Transcription factor 7-like 2 gene (TCF7L2) and peroxisome proliferator-activated receptors-γ2 (PPAR-γ2) have a profound effect on the incidence of type 2 diabetes mellitus (T2DM) and had previously been found to be associated with T2DM risk in various ppopulations. However, studies in the Arab population are inconsistent. We conducted a case control study to confirm the association of variants rs10885409 of TCF7L2 and Pro12Ala (rs1801282) of PPAR-γ2 with risk of T2DM and related complications in Emirati population of Arab origin. We also investigated the interaction of these associations with obesity status. METHODS: DNA was extracted from the saliva samples of 272 T2DM patients and 216 nondiabetic Emiratis. Genotyping for rs10885409 (TCF7L2) and rs1801282 (PPAR-γ2 P12A) variants was accomplished with a TaqMan assay. The subgroups were constituted according to obesity status. RESULTS: In the nonobese group, the rs10885409 C allele in the recessive model was significantly associated with the incidence of T2DM (OR 1.975 [95% CI 1.127-3.461], P = 0.017), but this association was not observed in the obese group or when BMI was not considered. PPAR-γ2 risk allele Pro12 frequency (0.96) was similar in the groups tested and more than 90% population was homozygous for this allele. CONCLUSIONS: Our case-control study is the first of its kind in Emiratis which establishes TCF7L2 rs10885409 C allele as a T2DM risk factor in Emiratis and this association is modulated by obesity status. We also confirmed that Pro12Ala mutation in PPAR-γ2 is not associated with T2DM risk in this population.