[The possibility of hereditary factors in the susceptibility to diabetic nephropathy in NIDDM].

Diabetic nephropathy is the most important complication of diabetes, because it is a major cause of morbidity and mortality for diabetic subjects. Since not all subjects with diabetes are at risk of developing this complication, we conducted a study to determine if heredity might be a possible risk factor for diabetic nephropathy in non-insulin dependent diabetes. Twenty-one factors including inheritance of nephropathy and hypertension were investigated in 109 individuals with NIDDM: 50 patients without proteinuria (Group I), 20 patients with intermittent proteinuria (Group II), and 39 patients with continuous proteinuria (Group III) matched for age and duration of diabetes. Of those patients, 55 patients with inheritance of diabetes were also divided into three groups: 29 patients without proteinuria (Group I), 9 patients with intermittent proteinuria (Group II), and 17 patients with continuous proteinuria (Group III). Individuals in Groups II and III has significantly higher frequency of inheritance of diabetic nephropathy than those in Group I, and also individuals with inheritance of diabetic nephropathy had significantly higher frequency of diabetic nephropathy than those without it. Frequency of hypertension, retinopathy and body mass index in the past were significantly higher in subjects in Groups II or Group III than in those in Group I. There were no significant differences between subjects in Groups II and III. These findings suggest that susceptibility to diabetic nephropathy in NIDDM may be hereditary, although hypertension and obesity may also be important risk factors for diabetic nephropathy.