Diabetes mellitus in familial hyperlipoproteinemia.

The relationship between a certain form of type 2 diabetes mellitus and familial endogenous hyperlipoproteinemia still remains confused. Therefore, we examined glucose tolerance and insulin secretion in 133 members (6-80 years old) of 15 families with a history of endogenous hyperlipoproteinemia. A segregation study was carried out to compare the prevalence of diabetes in hyperlipoproteinemic and normolipoproteinemic relatives, and the results seemed to support the recent concept that diabetes and hyperlipoproteinemia are inherited independently. However, the age-group analysis revealed that insulin secretion was progressively impaired with aging and about a third of the elderly group was significantly insulinopenic. Diabetes thus occurred in 0-2.6% of subjects under 40 years of age, 9.8% of those of 41-60 years of age and in 26.3% of those over the age of 61 years, occasionally complicated by diabetic retinopathy. Interestingly, insulinopenic diabetes was not accompanied by hyperlipoproteinemia, but hyperinsulinemic cases remained hyperlipoproteinemic. Therefore, the possibility arises that the independent occurrence of diabetes mellitus and hyperlipoproteinemia suggested by this crosssectional segregation study may result from bidirectional deviations in individuals who started out with uniform familial disorders such as insulin resistance.