PCSK9 and Hypercholesterolemia: People with mutations in ApoB and LDLR can develop hypercholesterolemia, as can people with mutations in both ATP-binding cassette transporters (ABCG5 and ABCG8) and the gene called autosomal recessive hypercholesterolemia, which encodes for the LDLR adaptor protein called PCSK9 [58].