AN ASSOCIATION IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS SUBJECTS BETWEEN SUSCEPTIBILITY TO RETINOPATHY AND TUMOR-NECROSIS-FACTOR POLYMORPHISM

In IDDM an association between diabetic retinopathy and polymorphic ma rkers of MHC has been described. However, these associations are compl icated by a primary association between the MHC and IDDM. Because the pathogenesis of retinopathy is likely to be the same in IDDM and NIDDM , NIDDM subjects with retinopathy would be the ideal population to stu dy for an association with MHC markers. The following South Indian sub jects were therefore studied: unselected NIDDM (n = 76), unselected ID DM (n = 99), non-diabetic controls (n = 96), NIDDM subjects with macul opathy (MAC), n = 55, NIDDM subjects with proliferative retinopathy (P R), n = 53, and without retinopathy (LTD), n = 46. DNA was amplified a nd studied using a microsatellite polymorphism located 3.5 kb upstream of TNF-beta within the MHC class III region on the short arm of chrom osome 6. No differences in allelic distribution were observed between the random NIDDM subjects and controls (p = 0.17). Differences in alle lic distribution were found between unselected IDDM and controls (p = 0.016) and between the NIDDM subjects with maculopathy and/or prolifer ative retinopathy and no retinopathy (p = 0.006). This association cou ld be accounted for by those patients with proliferative retinopathy ( MAC vs LTD, p = 0.23; MAC vs PR, p = 0.07; and PR vs LTD, p = 0.002).