Longitudinal Differences in Familial Combined Hyperlipidemia Quantitative Trait Loci

Abstract

To the Editor: Familial combined hyperlipidemia (FCHL), associated with premature cardiovascular disease, is the most common genetic hyperlipidemia with an estimated prevalence of 1%.1 The complex genetic background of FCHL is slowly being dissected through genome screens and positional candidate association studies.2–6 However, it has also been argued that although numerous studies have been conducted and reported, there are many conflicting results and a true understanding of the genetics remains largely unknown.7 Previously in this journal, we reported 4 quantitative trait loci (QTL) for apolipoprotein B (apoB), cholesterol, and triglycerides with P <0.001 in 22 FCHL pedigrees from Maastricht, in The Netherlands.8 The original QTL study was based on the premise that because FCHL is defined by increased serum levels of cholesterol, apoB, and triglycerides in families, QTL analyses of these quantitative traits in FCHL families might identify important genetic loci for this disorder. This letter reports QTL analyses of 5-year follow-up data in the same individuals. Longitudinal studies show that the lipid …