NATURE OF THE FAMILIAL INFLUENCE ON PLASMA-LIPID LEVELS

In order to test for the presence of 'major' genetic factors influencing plasma concentration of CH and TG a sample of nearly 500 nuclear families, each including father, mother and two or more natural children, was drawn from the general, well population of the Toronto-Hamilton region. Patterns suggestive of segregation were obtained from statistical analysis of plasma concentrations expressed on the scale of mg/100 ml and weaker, but possibly more valid authentic patterns, from measurements expressed on a logarithmic scale. In particular, CH variance was significantly increased in the progeny of subjects with hyperalphalipoproteinemia and of those with Type II HLP, while TG variance was increased in the progeny of subjects with Type IV HLP. The resulting contribution to total population variance at childhood ages, however, appears to be rather small. An analysis of the same data in terms of correlation coefficients showed that familial factors influencing lipid levels have a fairly high degree of specificity as between CH and TG, and apply in the lower as well as the upper range of plasma concentrations. Familial correlations tend to be stronger for blood relatives than for unrelated members of the same household, stronger for CH than for TG, stronger for mothers than for fathers, and stronger for younger than for older children. © 1979.