Calpain 10 gene SNP-44 T>C polymorphism in type 2 diabetes mellitus of Bangladeshi origin

Abstract

Insulin resistance and/or B cell secretory defect have been accepted as the fundamental features in the pathogenesis of type 2 diabetes mellitus, though the exact molecular defect affecting the insulin secretion or sensitivity still to be clearly elucidated. The present study was undertaken to determine CAPN 10 gene SNP-44 T>C polymorphism in Bangladesh type 2 diabetes mellitus and explore its relationship with its insulin secretory capacity and insulin sensitivity. A total number of 65 T2DM subjects were recruited and 91 subjects served as control. Glucose was measured by glucose-oxidase, lipids by enzymatic-colorimatric, insulin by ELISA methods. Homeostatic model assessment was used to calculate pancreatic B cell secretion, expressed on HOMA%B and insulin sensitivity, 1-IOMA%S. DNA was extracted using QIAGEN spin column blood DNA kit. CAPN 10 gene polymorphic marker was determined by mutation specific PCR. Data were managed by statistical package for social science (SPSS). P<0.5 was taken as level significance. T2DM and Control subjects were age and BMI matched. Fasting serum insulin (μU/ml, mean±SD) in the T2DM subjects was significantly higher compared to controls (7.97±3.83 vs 5.01±0.57). Insulin secretory capacity (HOMA%B) in the T2DM group and the controls did not show any significant difference (p=0.240). Insulin sensitivity (I-IOMA%S) was significantly lower in the T2DM group compared to the controls (48.9±21.7 vs 79.9±20.5) (p<0.001). CAPNIO gene SNP-44 genotype frequencies for the T2DM were 0.662, 0.323 and 0.150 for Wild, Ht and Hz variant respectively and in the controls the frequencies were 0.670, 0.297 and 0.330 respectively, which did not show any significant association with diabetes mellitus. Subjects with variant (TC and TT) genotype did not show significant difference regarding glucose, BMI, HOMA%B, HOMA%S either in the T2DM or control group. In conclusion (i) CAPN 10 SNP 44 T>C polymorphism was not associated with T2DM of Bangladeshi origin. (ii) Insulin sensitivity appeared to be predominant in the subsets of T2DM subjects, and (iii) CAPN 10 SNP 44 T>C variant did not show any relation with pancreatic B cell secretion and insulin sensitivity of the study subjects.