Multivariate genetic analysis of high density lipoprotein particles

The aim of this study was to investigate the effect of genetic factors on three components of plasma high density lipoproteins, HDL-cholesterol (HDL-C), apolipoprotein A-I (apo A-I) and lipoprotein particle Lp A-I (Lp A-I), which contains apo A-I but not apo A-II. These analyses were carried out on 106 nuclear families with one or more children (407 subjects) who volunteered for health screening at the Center for Preventive Medicine, Vandoeuvre, France. After adjustment by stepwise multiple linear regression analysis for age, gender, weight, height, ponderosity, alcohol consumption, smoking habits, and hormonal treatment in females, a multifactorial model (considering the effect of polygenes, individual, specific, environmental and common household factors) was fitted to each variable separately. The hypothesis of no common household effects was accepted for each of the traits. The contribution of genetic factors to inter-individual variance was larger than the contribution of environmental factors for apo A-1 ( h 2 = 0.81) and Lp A-I ( h 2 = 0.63) but not for HDL-C ( h 2 = 0.44). Bivariate analyses were carried out by parameterizing covariance components between traits. The genetic correlations were always significantly different from zero. They were estimated to be 0.73 between HDL-C and apo A-I, 0.40 between HDL-C and Lp A-I, 0.51 between apo A-I and Lp A-I. These results suggest that HDL-C, apo A-I and Lp A-I are only in part affected by the same genes and that the measurement of lipids as well as the apo A-I and Lp A-I gives complementary and different information on the metabolic and genetic aspects.