Familial hypercholesterolemia: From genetic and clinical diversity towards tailored therapy

Patients with familial hypercholesterolemia (FH), a common monogenic disorder with a prevalence of approximately in 1:200-250, are at extreme risk for cardiovascular disease. Lifelong exposure to extreme plasma levels of LDL-cholesterol leads to accumulation of cholesterol in the arterial wall resulting in premature atherosclerosis. If left untreated, a large proportion of patients with FH will suffer from the clinical consequences thereof, and will experience their first cardiovascular event before the age of 60 years. Therefore, early detection of FH is important, as it allows for early initiation of lipid lowering therapy in order to prevent mortality and morbidity due to cardiovascular disease. FH is an autosomal dominant disease caused by pathogenic variants in one of the three known FH genes: LDLR, APOB and PCSK9. However, a pathogenic genetic variant in the coding regions of these genes is not identified in a substantial part of patients with a clinical diagnosis of FH. The overall aim of the studies described in this thesis is to enlarge our understanding of the phenotypic differences among patients with FH. Moreover, the role of putative and novel genomic variants in FH is investigated. Lastly, it addresses whether PCSK9 inhibition, a relatively novel LDL-c lowering therapy, is safe and efficacious in a specific patient category (i.e. biallelic FH), what the potential impact of wide use of PCSK9 inhibition would be, and what the effect of PCSK9 inhibition is in a real world clinical setting.