Molecular Genetic Approach and Evaluation of Cardiovascular Events in Patients with Clinical Familial Hypercholesterolemia Phenotype from Romania

Abstract

This study identifies the genetic background of familial hypercholesterolemia (FH) patients in Romania and evaluates the association between mutations and cardiovascular events. We performed a prospective observational study of 61 patients with a clinical diagnosis of FH selected based on Dutch Lipid Clinic Network (DLCN) and Simon Broome score between 2017 and 2020. Two techniques were used to identify mutations: multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. The mutation rate was 37.7%, i.e., 23 patients with mutations were identified, of which 7 subjects had pathogenic mutations and 16 had polymorphisms. Moreover, 10 variants of the low-density lipoprotein receptor (LDLR) gene were identified in 22 patients, i.e., one variant of the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene in six patients, and one variant of the apolipoprotein B (APOB) gene in three patients. Of the LDLR gene variants, four were LDLR pathogenic mutations (c.81C > G, c.502G > A, c.1618G > A mutations in exon 2, exon 4, exon 11, and exon 13–15 duplication). The PCSK9 and APOB gene variants were benign mutations. The pathogenic LDLR mutations were significant predictors of the new cardiovascular events, and the time interval for new cardiovascular events occurrence was significantly decreased, compared to FH patients without mutations. In total, 12 variants were identified, with four pathogenic variants identified in the LDLR gene, whereas 62.3% of the study population displayed no pathological mutations.

Genetic Testing for Familial Hypercholesterolemia in a Pediatric Group: A Romanian Showcase

“…Another recent study, describing the variants related to FH in the Romanian adult population, has been published [ 62 ] and identifies three out of the four mutations on the LDLR gene that we report (c.1618G>A, c.502G>A and c.81C>G). Variants c.1618G>A and c.81C>G are also mentioned in several Chinese study groups [ 60 , 61 ].…”

“…The LDLR c.1618G>A, p.(Ala540Thr) missense variant, detected in one index patient, is also a commonly occurring variant among Romanian patients and has been described in several European, Latin American and even Chinese populations [ 56 , 60 , 61 , 62 ]. It is located in the epidermal growth factor (EGF)-precursor homology domain.…”

“…In our study, two patients had APOB mutation (one likely pathogenic and one variant of unknown significance). In another Romanian study, there was only one APOB mutation identified (c.10740C>T) [ 62 ]. This mutation was not present in our study.…”

“…In our study, there were two patients with the same PCSK9 mutation. NM_174936.4:c.836C>T, currently assessed as a variant of unknown significance, was not identified in the Romanian study published in 2021 [ 62 ].…”

Analysis of Rare Variants in Genes Related to Lipid Metabolism in Patients with Familial Hypercholesterolemia in Western Siberia (Russia)

“…MLPA is necessary for the diagnosis of familial hypercholesterolemia in patients without functionally significant point substitutions in relevant genes to which one of the sequencing methods has been applied [59]. Wider use of the MLPA method should help to identify 2-3% more probands with familial hypercholesterolemia.…”