Mild Familial Diabetes with Dominant Inheritance

Abstract

Three families have been described in which diabetes, although usually diagnosed in the teens or early 20s, is mild and does not progress to insulin dependence even over a period of 40 years. This syndrome seems to be inherited as a Mendelian dominant because (1) there is direct parent to child inheritance through at least three generations (2) the ratio of affected: unaffected children of diabetic parents is 1:1 and (3) almost all affected individuals have a diabetic parent. Complications are uncommon and mild. Seven out of 12 diabetics diagnosed under the age of 30 and having a mean duration of diabetes of 37 years did not have any retinopathy. No death from diabetes has ever been recorded in any of the families. In two families diabetes is associated with a low renal threshold for glucose. This syndrome is distinct from the more usual type of juvenile diabetes mellitus and provides evidence of the genetic heterogeneity of diabetes mellitus.