Verification of Underlying Genetic Cause in a Cohort of Russian Patients with Familial Hypercholesterolemia Using Targeted Next Generation Sequencing

Abstract

Russian patients with familial hypercholesterolemia (FH) were screened for pathogenic mutations using targeted next generation sequencing. Genetic testing was performed in 52 probands with definite or probable FH based on the Dutch lipid clinic network criteria (DLCN score ≥ 6). Blood samples were studied by massive parallel sequencing (Illumina HiSeq 1500 platform) using a custom capture library related to dyslipidemia and premature atherosclerosis. Mutations considered to be responsible for monogenic FH were identified in 48% of the probands: 24 with mutations in the LDLR gene and two with a mutation in the APOB gene. There were 22 pathogenic/likely pathogenic mutations in LDLR, eight of which have not been previously described in the literature. Four patients with a clinical picture of homozygous FH had two heterozygous LDLR mutations. Although mutation-negative patients had highly elevated total cholesterol and low-density lipoprotein cholesterol levels, only half of them had a family history of hypercholesterolemia. With respect to heterozygous FH, mutation-positive patients had higher maximum total cholesterol levels (p = 0.01), more severe carotid atherosclerotic lesions, and a higher percentage of premature peripheral artery disease (p = 0.03) than mutation-negative ones. However, the number of patients who suffered from myocardial infarction was similar between the two groups.

Keywords

• familial hypercholesterolemia
• next generation sequencing
• LDLR
• Dutch lipid clinic network criteria
• cardiovascular risk