The identification of PCSK9 as the third gene responsible for autosomal dominant hypercholesterolemia was a groundbreaking discovery, as it linked gain-of-function mutations in PCSK9 to familial hypercholesterolemia, while loss-of-function mutations were associated with lower LDL cholesterol (LDL-C) levels and reduced cardiovascular risk [3, 4]. This evidence concerns the gene PCSK9 and familial hypercholesterolemia.