Insulin-dependent diabetes mellitus (IDDM) is an autoimmune disease with a strong genetic component. The role of the HLA region on chromosome 6p21 (IDDM1) in the genetic predisposition to IDDM is well established, but the HLA genes can explain only 50% of genetic risk. The aim of this study was to analyze the role of the insulin gene region on chromosome 11p15 in the genetic predisposition to IDDM in a Polish population. The studied group consisted of 66 unrelated IDDM patients from a region of Central Poland and 64 unrelated, healthy persons, mainly blood donors, from the same region, which constituted the control group. Allelic distribution of two RFLP polymorphism's, -23 HphI and +805 DraIII from the insulin gene region, were studied by the PCR-RFLP method. Allelic distribution of these two polymorphisms was different in the diabetics than in the control group. The (+/+) genotype of -23 HphI polymorphism was present in 83.3% of IDDM patients and in 54.7% of healthy subjects (RR=4.2; p<0.001). The (-/-) genotype of +805 DraIII polymorphism was found in 86.4% of IDDM patients and in 59.4% of subjects in control group (RR=4.4 p<0.0005). These results clearly show the association of the insulin gene region on chromosome 11p15 with insulin-dependent diabetes mellitus in a Polish population.

Keywords: insulin-dependent diabetes mellitus, insulin gene region, Genetics, polymorphisms