Insulin promoter VNTR polymorphisms: interactions and association with type 1 diabetes mellitus in Bengali speaking patients of Eastern India

Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease characterized by an absolute insulin deficient production by the pancreatic [beta]-cells. The purpose of the present study was to measure rs689 frequencies and its association in T1DM cases and controls originating from West Bengal region of India. The rs689 single nucleotide polymorphism was genotyped using PCR and sequencing protocol. The genotype and allele frequencies of rs689 did not differ significantly between T1DM group and control groups. However, C-peptide levels differed significantly among the genotypes of rs689 in T1DM patients (P = 0.042). The biochemical (GAD, IA-2) and anthropometric (BMI, WHR) analysis failed to show significant association between the patients and controls among rs689 genotypes. Screening of additional samples from eight tribal populations revealed the presence of the TT mutation (INS VNTR-class III). In conclusion, the INS gene rs689 does not have a key role in conferring the risk in T1DM patients from Eastern India. Key words: INS, type 1 diabetes mellitus, single nucleotide polymorphism, India