The relative importance of common and rare genetic variants in the development of hypertriglyceridemia

David Evans*ab, Jens Aberleaa & Frank-Ulrich Beilaaa Endokrinologie und Stoffwechsel, Medizinische Klinik III, Zentrum für Innere Medizin, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germanyb † Author for correspondencePlasma lipid levels are a complex trait with a genetic and an environmental component. There are two models for the genetic basis of complex traits: the common-disease common-variant hypothesis, in which susceptibility is due to variants occurring at relatively high frequency but low effect size; and the common-disease rare-variant hypothesis, where disease is due to multiple rare variants each occurring at low frequency but with high effect size. Genome-wide association studies have identified a number of common variants associated with plasma lipid levels. However, they account for only a proportion of the genetic variance. Resequencing studies are revealing the importance of rare variants in accounting for the missing variance. Next-generation sequencing will allow the relative importance of the two hypotheses to be assessed.