[Studies on the heredity and pathogenesis of familial combined hyperlipidemia ("multiple lipoprotein type"...

A family with familial combined hyperlipidemia (multiple-lipoprotein type hyperlipidemia) was investigated with regard to mode of inheritance, phenotypic expression, presence of genetic markers, and biochemical parameters related to lipid metabolism. The family of 22 subjects (13 males, 9 females) was composed of 5 type IIa, 8 type IIb, 1 type IV hyperlipoproteinemias and 5 normolipidemics. The distribution of serum cholesterol and serum triglyceride concentration was bimodal. No relationship was observed between hyperlipidemia and blood groups or histocompatibility antigens. Subjects with high HLA 8 or W 15 had, on the average, higher lipid levels than others. However, these antigens were observed in normolipidemics too. The response to therapy with alufibrate (2g/day) was not uniform. Subjects with marked triglyceride lowering exhibited only moderate cholesterol lowering, and marked cholesterol lowering was associated with poor triglyceride lowering. The reduction in serum lipids was observed in unaffected family members as well. It is therefore concluded that alufibrate does not exert an effect on the defect in familial combined hyperlipidemia but on some unspecific sites probably on lipoprotein lipase. The familial combined hyperlipidemia appears to be transmitted in an autosomal dominant mode and very probably determined by more than one gene.