This study aimed to evaluate the causal relationship between lipid phenotypes mediated by lipid-lowering drug targets—3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMGCR), proprotein convertase subtilisin/kexin type-9 (PCSK9), and Niemann-Pick C1-like 1 (NPC1L1)—and the risk of cystic kidney disease and PKD. The gene discussed is PCSK9; the disease is cystic kidney disease.