Effect of mutations in LDLR and PCSK9 genes on phenotypic variability in Tunisian familial hypercholesterolemia patients

► Phenotypic expression in Tunisian familial hypercholesterolemia varied widely. ► We identified a new putative loss of function mutation in PCSK9 gene: p.P174S. ► Variants of PCSK9 and APOE genes explain a part of the phenotypic variability.