Genetic Architecture and Cardiovascular Risk of Familial Combined Hyperlipidemia

Abstract

<h3>Lead Author's Financial Disclosures</h3> Nothing to disclose. <h3>Study Funding</h3> None. <h3>Background/Synopsis</h3> Familial combined hyperlipidemia (FCHL) is one of most common inherited lipid phenotypes and is characterized by elevated plasma concentrations of apolipoprotein B-100 and triglycerides. However, many aspects of FCHL remain incompletely understood, such as its genetic basis and the magnitude of cardiovascular risk with which it is associated. <h3>Objective/Purpose</h3> The goals of this study were to investigate the genetic architecture and cardiovascular risk associated with FCHL. <h3>Methods</h3> We identified individuals with a FCHL phenotype among 349,222 unrelated participants of European ancestry in the UK Biobank using modified versions of 5 different diagnostic criteria. The prevalence of the FCHL phenotype was 11.44% (n=39,961), 5.01% (n=17,485), 1.48% (n=5,153), 1.10% (n=3,838), and 0.48% (n=1,688) according to modified versions of the Consensus Conference, Dutch, Mexico, Brunzell, and Goldstein clinical criteria, respectively. We performed discovery, case-control genome-wide association studies for these different FCHL criteria. <h3>Results</h3> We identified 175 independent loci associated with FCHL at genome-wide significance. All loci have known associations with plasma lipid levels. We investigated the combined impact of genetic and environmental risk on FCHL and found that the combination of polygenic susceptibility to hypercholesterolemia or hypertriglyceridemia and features of metabolic syndrome was associated wa ith greater prevalence of FCHL. Lastly, we observed that individuals with an FCHL phenotype had a comparable risk of incident coronary artery disease compared to individuals with monogenic Familial Hypercholesterolemia (FH) (adjusted hazard ratio vs controls [95% confidence interval]: 2.72 [2.31-3.21] and 1.90 [1.30-2.78]) <h3>Conclusions</h3> Our results suggest that, rather than being a single genetic entity, the FCHL phenotype represents a polygenic susceptibility to dyslipidemia in combination with metabolic abnormalities. Importantly, the cardiovascular of the FCHL phenotype is similar to that of monogenic FH, despite being at least 5 times more common.