Functional studies of six unchareacterized mutations in low-density lipoprotein receptor gene

GÓMEZ, ANDREA; TOSCANINI, ULISES; GIUNTA GUSTAVO; CUNIBERTI LUIS ALBERTO; HELMAN, LORENA

Rosario

Congreso; REUNION ANUAL SAFIS 2019; 2019

SOCIEDAD ARGENTINA DE FISIOLOGIA

Introduction: Familial Hypercholesterolemia (FH) is a primary hyperlipemia. It is an autosomal dominant genetic disorder of lipoproteins metabolism mainly caused by mutations in the lipoprotein receptor gene (LDLR). Aim: We aimed to investigate the functional impact on the low density lipoprotein receptor (LDLR) activity of six uncharacterised variants located in the coding region of the LDLR gene, namely c.428G>T, c.640T>C, c.1708C>T, c.1736A>T, c.1981C>G and c.2114C>G (NM_000527.4) and to attempt to define their clinical status. Material and Methods: Functional studies were carried out using site-directed mutagenesis techniques and expression of LDLR protein in vitro. Results were correlated with clinical data and in silico analyses in order to assess the physiopathological role of these variants. Results: This work provides functional information about 6 uncharacterized mutations in LDLR. The six variants studied here appeared to affect the LDLR function in vitro to different degrees, ranging from receptors with normal to slightly reduced activity to receptors exhibiting less than 10% of the wild-type activity.Conclusion: According to these studies and The American College of Medical Genetics and Genomics (ACMG) Standards and Guidelines, two variants could be classified as ?Likely Benign? (p.(Ala705Gly) and p.(Leu570Phe)), three variants as ?Pathogenic? (p.(Asp579Val), p.(Cys143Phe) and p.(Trp214Arg)) and one variant as ?Likely Pathogenic? (p.(Pro661Ala)).