By exploiting the functions of Proprotein convertase subtilisin/kexin type 9 (PCSK9), a protein that directs hepatic LDL receptors for degradation [11], it was shown that a single injection of recombinant adeno-associated virus (rAAV) encoding gain-of-function mutant forms of PCSK9, human PCSK9D374Y or mouse PCSK9D377Y (AAVmPCSK9), was sufficient to reduce LDL receptor expression, increase plasma LDL cholesterol and induce atherosclerosis in mice and hamsters [9, 10]. The gene discussed is PCSK9; the disease is atherosclerosis.