The association between the HLA system and retinopathy development in patients with type 1 diabetes mellitus.

Duration of diabetes and chronic hyperglycemia are the most important risk factors in the pathogenesis of diabetic retinopathy (DR). However, there is increasing evidence suggesting that genetic factors may also contribute to its development. The aim of this study was to determine the role of the HLA system in the development of DR in patients with type I diabetes mellitus. Class H genes (DRB1, DQB1) were typed using the PCR-SSP method. Based on the fundus examination the patients were divided into two groups: one group with no or mild nonproliferative diabetic retinopathy (NPDR) and the other group with severe/very severe NPDR or proliferative diabetic retinopathy (PDR). The study confirms the influence of HLA genes in the development of DR in Croatian type I diabetic patients. In our patients, susceptibility to PDR appears to be primarily associated to DQB1*0201 with the relative risk, RR =5.29 and DQB1*0302 (RR =2.84). However, a strong positive correlation between DR and alles DRB1*0301 (RR =2.12) and DRB1*0402 (RR =3.01) was also found.