Reduced Lipoprotein(a) Associated With the Apolipoprotein E2 Genotype Confers Cardiovascular Protection in Familial Hypercholesterolemia

There are 3 isoforms of apolipoprotein E (apo E) in humans (ε2, ε3, and ε4). They differ by single amino acid substitutions that variably affect their affinity for the low-density lipoprotein receptor (LDLR) and for the LDLR-related protein (LRP1), with ε2 having the weakest binding to these receptors (1). The plasma levels of lipoprotein(a) [Lp(a)], a highly atherogenic LDL-like lipoprotein species, are influenced by the polymorphism of apo E, with ε2/ε2 and ε4/ε4 carriers presenting with the lowest and highest Lp(a) plasma concentrations, respectively (1).