Pediatric hyperlipoproteinemia: the phenotypic expression of hyperapobetalipoproteinemia in young probands and their parents.

These data on families of pediatric probands with the hyperapoB phenotype confirm and extend our previous findings of familial aggregation of hyperapoB and document further the expression of hyperapoB in the pediatric age group (Sniderman et al, 1985). In agreement with a more recent report (Beaty et al, 1986) the data suggest, but do not prove, the presence of a Mendelian dominant trait for hyperapoB. The observation that most of the parents affected with hyperapoB were normolipidemic clearly suggests a difference between the expression of hyperapoB in these families and FCH. Further studies on the basic biochemical and genetic defect(s) underlying these common disorders associated with CHD will be necessary to provide a better understanding of the pathogenesis of these important lipoprotein disorders. A significant proportion of children referred to a Lipid Clinic for suspected hyperlipidemia or because of a family history of premature CHD may have hyperapoB. We suggest that measurement of plasma LDL B be added to the standard measurements of lipids and lipoproteins made in Lipid Clinics and that further studies be performed on the utility of using the ratio of LDL C/B as a useful clinical tool to differentiate between those patients with hyperapoB and those with more conventional type II hyperlipoproteinemia.