However, its functional impact is poorly understood.<h4>Objective</h4>To determine the functional impact of the exon13_15dup variant in the LDLR, in familial hypercholesterolemia patients.<h4>Methods</h4>Three heterozygous carriers of an exon 13-15 duplication and five wild type subjects were recruited. The gene discussed is LDLR; the disease is familial hypercholesterolemia.