The Pro12Ala PPARg2 gene polymorphism involves residual C-peptide secretion and BMI in type 1 diabetes

Introduction and aim. Since insulin resistance is genetically determined and observed in type 1 diabetes, the study was designed to elucidate an involvement of Ala 12 Pro PPARg2 gene polymorphism in residual C-peptide secretion and BMI variation in children with type 1 diabetes. Material and methods. In 103 patients with type 1 diabetes genetic analysis of PPARg2 polymorphism, C-peptide measurements and evaluation of BMI and clinical parameters were performed. Control group consisted of 109 healthy subjects. Results. In diabetic patients, only three individuals exhibited Ala 12 Ala genotype (2.9%) and 29 patients were heterozygous Ala 12 Pro (28.2%). Interestingly, Ala12+ variants were associated with higher C-peptide levels in 6 th , 12 th and 24 th months after the onset than Pro 12 Pro genotype (0.39±0.24 pmol/mL vs. 0.22±0.14 pmol/mL, P=0.007 and 0.19±0.09 vs. 0.11±0.07, P=0.01 and 0.13±0.09 vs. 0.07±0.05, P=0.021, respectively). Similarly, C-peptide was also significantly increased in patients with history of type 2 diabetes in the first-degree relatives. The observation was even more evident when Ala12+ variants were taken together with family history of type 2 diabetes. Besides, in 24 th and 36 th months after the onset, Ala12+ variants revealed to be associated with higher BMI normalized by age and sex as compared to Pro 12 Pro (0.557±0.84 vs. -0.119±0.73, P=0.001 and 0.589±0.919 vs. 0.066±0.630, P=0.016, respectively). Conclusions. Thus, it is likely that PPARg2 gene polymorphism and/or the genetically determined insulin resistance may be associated with residual C-peptide secretion and involve excessive BMI in type 1 diabetes.