FAMILIAL INFLUENCE ON TYPE-1 (INSULIN-DEPENDENT) DIABETES-MELLITUS BY RELATIVES WITH EITHER INSULIN-TREATED OR TYPE-2 (NON-INSULIN-DEPENDENT) DIABETES-MELLITUS

In 161 patients with Type 1 (insulin-dependent) diabetes mellitus, the familial influences by first-degree relatives with insulin-treated diabetes mellitus (ITDM), and by first-degree relatives with Type 2 (non-insulin-dependent) diabetes mellitus were investigated. A control group consisted of 730 subjects with normal glucose tolerance. Independent odds ratios (adjusted for covariates) for Type 1 diabetes in offspring were 7.0 (p < 0.001) with first-degree ITDM relatives, and 2.5 (p < 0.01) with first-degree Type 2 diabetic relatives. When relatives were separated into parents and siblings, odds ratios for Type 1 diabetes in offspring were higher due to paternal ITDM and paternal Type 2 diabetes, than in cases of maternal diabetes. Siblings with ITDM, but not siblings with Type 2 diabetes, also showed increased odds ratios. Thus, both familial ITDM and familial Type 2 diabetes showed influences in separate ways on the presence of Type 1 diabetes in offspring, indicating separate genetic mechanisms.