Further studies on serumα1-lipoprotein in familial lecithin:cholesterol acyltransferase deficiency

Serum high density lipoprotein (HDL) from two patients with LCAT deficiency has been compared with HDL from normal subjects and HDL from a presumed heterozygous carrier. By two different immunological methods the concentration of -lipoprotein in serum of the patients was found to he about 25–30 % of the normal concentration. Patient HDL is cornpoked of two fractions, as shown previously. The first fraction contains particles of high molecular weight with an electrophoretic mobility slightly slower than that of normal HDL. The lipid content is 70%, and the concentrations of unesterified cholesterol and phospholipids are about 10–15 and 3–4 times that of normal HDL, respectively. The second fraction consists of particles of relatively low molecular weight with electrophoretic mobility faster than albumin. This fraction exhibits closc to normal concentrations of unesterified cholesterol and phospholipids. Esterified cholesterol or lysolccithin could he demonstrated in none of the fractions. HDL from the prewmed hetcrozygous carrier was normal as judged from immunoelectro-phoresis, gel filtration, electron microscopy. and lipid analyses.