A pedigree of homozygous familial hyperalphalipoproteinemia

Abstract

A new form of familial lipoprotein disorder, homozygous hyperalphalipoproteinemia (HALP) was studied in one pedigree through three generations. The proband was a healthy male, 50 years old, who was checked for a distinctive elevation of plasma high-density lipoprotein cholesterol (HDL-C) in a routine screening examination. An intensive family study revealed that the proband and one of his sisters were homozygotic carriers of familal HALP judging by their extremely high concentration of HDL-C (181 mg/dL and 163 mg/dL, respectively). In the homozygotes, the lipid composition of HDL was found to be normal while the ratio of HDL lipids to apoproteins A-I and A-II tended to be increased. All five children of the two homozygous individuals and two additional first degree relatives were considered to be heterozygous, since their HDL-C values were moderatey elevated, with other lipid levels being normal. The family study thus substantiated the hypothesis, as Glueck et al insisted in 1975, that this lipoprotein disorder is inherited by autosomal dominant transmission. Longevity analysis revealed that the decreased family members showed life prolongation of 9.8 years on an average compared with the appropriate control population of the same district. Our report might be the first to demonstrate the homozygous form of this longevity syndrome.