Molecular Characterization of Proprotein Convertase Subtilisin/Kexin Type 9 Gene Mutations in Vietnamese Patients with Hypercholesterolemia

Abstract

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an enzyme that plays a key role in regulating the circulating low density lipoprotein cholesterol (LDL-C). Among the PCSK9 variants, while gain-of-function mutations aggravate the degradation of LDL receptors, leading to familial hypercholesterolemia (FH), whereas loss-of-function mutations increase LDL receptor levels, lower LDL levels, and prevent coronary heart disease. The variants of PCSK9 have not been clarified in the Vietnamese population yet. Hence, the present study aimed to present the molecular characteristics of PCSK9 gene in Vietnamese hypercholesterolemia patients. A total of 26 peripheral blood samples were collected from the patients who were diagnosed with Hypercholesterolemia in a local hospital. The PCR-sequencing method was applied to amplify and sequencing PCSK9. Then, variant screening was performed by comparing with the reference sequence (NG_009061). 60 variants were identified in 14 of 26 patients (accounting for 53.85%): 50 (83.33%) variants were identified as novel variants among which, 24 were probably damaging, 11 were benign, and 15 were variants of uncertain significance. Functional effects of novel variants were predicted by using PolyPhen-2 and FSPLICE. This study analyzed the variants spectrum in Vietnamese Hypercholesterolemia patients and expresses the importance of genetic diagnosis in FH patients.