Bimodality of plasma apolipoprotein B levels in familial combined hyperlipidemia.
To investigate possible genetic influences on plasma apolipoprotein (apo) B levels in familial combined hyperlipidemia (FCHL), commingling analysis was performed on data from seven large kindreds, including 183 individuals. The overall frequency distribution of apo B was skewed and was compatible with the presence of two normally distributed subdistributions (mean values, 117 and 172 mg/dl). The analysis was repeated after stratification of individuals by low density lipoprotein (LDL) subclass phenotype. Among subjects with phenotype A (predominance of large, buoyant LDL), a single apo B distribution was found (mean, 115 mg/dl). Among subjects with phenotype B (predominance of small, dense LDL), the distribution was bimodal, with mean values, 116 and 167 mg/dl, similar to the unstratified data set. Thus the skewing of the overall apo B distribution in FCHL family members may be due to a distinct subset of individuals with phenotype B who are genetically susceptible to even higher elevations of apo B. The higher apo B/phenotype B subjects also showed significantly higher levels of triglyceride and LDL-cholesterol than the lower apo B/phenotype B subjects. The lower apo B/phenotype B subjects had higher triglyceride and lower LDL-cholesterol than the phenotype A subjects. The enhanced information regarding apo B and lipid levels in the three subgroups of individuals identified here may facilitate a better understanding of genetic susceptibility to coronary heart disease.
Austin
M A
MA
Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195.
Horowitz
H
H
Wijsman
E
E
Krauss
R M
RM
Brunzell
J
J
D000293:Adolescent; D000328:Adult; D001055:Apolipoproteins B / Q000097:blood*; D005260:Female; D006801:Humans; D006950:Hyperlipidemia, Familial Combined / Q000097:blood* / Q000235:genetics; D008055:Lipids / Q000097:blood; D008077:Lipoproteins, LDL / Q000097:blood / Q000145:classification / Q000235:genetics; D008297:Male; D010641:Phenotype
D001055:Apolipoproteins B; D008055:Lipids; D008077:Lipoproteins, LDL