Abstract 16962: The Genetic Basis of Hypercholesterolemia in a Community-Based Cohort

Abstract

Introduction: Prior reports of the genetic etiology of hypercholesterolemia are affected by referral bias, inclusion of individuals with secondary hypercholesterolemia and variability in identifying pathogenic variants. We sought to assess the prevalence of monogenic and polygenic etiologies in a community based cohort of adults with primary hypercholesterolemia (LDL-C ≥155 mg/dL after excluding secondary causes). Methods: We identified 1719 individuals aged 18-70 years with primary hypercholesterolemia from SE Minnesota. The Dutch Lipid Clinic Network (DLCN) score was ascertained by an electronic health record (EHR) based algorithm followed by manual review. Familial hypercholesterolemia (FH) was considered present with a DLCN score ≥6 whereas a DLCN score of 3-5 was considered possible FH. Participants underwent sequencing of FH genes ( LDLR, APOB, PCSK9 ) and genotyping of 12 SNPs known to be associated with LDL-C. Rare (frequency <0.1%) and putatively functional variants were identified and pathogenicity was assigned based on the ACMG guidelines using relevant database, literature and EHR review. A polygenic score (PGS) for LDL-C (derived from 12 SNPs) >90 th percentile was considered an indicator of polygenic etiology. Results: A pathogenic/likely pathogenic variant (16 in LDLR , 1in APOB and 2 in PCSK9 ) was present in 24 (1.3%) individuals, a PGS >90 th percentile was present in 265 (15.4%) and 4 (0.2%) had both a monogenic and polygenic etiology. The overall prevalence of an identifiable genetic etiology was 17%. Based on clinical criteria the overall prevalence of FH (DLCN ≥6) was 7.0% (6.1% probable and 0.9% definite) and that of possible FH was 30.0%. In the possible, probable and definite FH categories, a monogenic etiology was present in 2.4%, 9.5% and 26.7% and a polygenic etiology in 19.1%, 21.0% and 13.3% respectively. 52.0% of those with a monogenic etiology and 9.7% of those with a polygenic etiology met the DLCN criteria for FH. Conclusions: This study provides for the first time estimates of monogenic and polygenic etiology of hypercholesterolemia in adults from the community, excluding cases of secondary hypercholesterolemia and using standardized methods of variant annotation.