Broad-beta disease (type III hyperlipoproteinemia) in a large kindred. Evidence for a monogenic mechanism

The inheritance of broad-beta disease (as specified by a type III lipoprotein pattern) has remained an enigma. Previous reports have variously implicated a single gene (autosomal dominant mode), a double dose of a single gene (autosomal recessive), two separate genes (mixed heterozygosity), or multiple genes (polygenic inheritance). The present study of a single, large kindred of 108 members spanning 4 generations provides evidence for an autosomal dominant mode, since at least 1 member of the first generation pair was normal, at least 5 of their 9 children had type III patterns, and at least 2 of these (whose spouses were normal) transmitted this pattern to their offspring. The findings also suggest that in this kindred the common occurrence of hypertriglyceridemia (in a type IV pattern) may represent either a variable phenotypic expression of the gene for broad-beta disease or the coexistence of a second, independent genetic lipid disorder.

1,2-3-H cholesterol as a tracer in studies of human cholesterol metabolism

1,2-(3)H-Cholesterol was fed to a subject together with 4-(14)C-cholesterol at a known (3)H/(14)C ratio. The ratio was satisfactorily preserved in cholesterol recovered from plasma, red cells, and bile, and in bile acids of bile. Isotopic fractionation was seen during thin-layer chromatographic isolation of cholesterol. In work with 1,2-(3)H-cholesterol or its metabolites care should be taken to recover chromatographic bands in their entirety.