Mutational screening in the LDLR gene among patients presenting familial hypercholesterolemia in the Southeast of Brazil.

Abstract

Familial hypercholesterolemia (FH) is a dominant, autosomal disease characterized by high LDL levels in blood plasma, and is caused by a defect in the gene encoding the LDL receptor (LDLR). The clinical diagnosis is based on personal and familial history, physical examination findings, and measures of high LDL cholesterol concentrations. LDLR is a cell-surface glycoprotein that controls the level of blood plasma cholesterol and triglyceride by LDLR-mediated endocytosis. Here we sequenced the entire LDLR gene-coding region to screen for mutations in 32 patients diagnosed with FH, and we have found 20 mutations including synonymous, missense, and intronic mutations. Six of them were characterized as pathogenic mutations (D178Y, C184Y, S326C, C681X, IVS7+10G>C, and IVS11-10G>A). We have also found one intronic mutation not described so far (IVS11-63C>A). Our study corroborates the broad spectrum of mutations distributed along the entire LDLR gene, and we suggest that the genes APOB and PCSK9 should also be screened for mutations when considering the diagnosis of FH. It is already known that different types of mutations are directly associated with the phenotype heterogeneity presented by patients. Considering that Brazilian population is highly admixed, it is important to determine the geographic spectrum of LDLR mutations to provide information on the prognosis and treatment of each FH patient.