The role of PCSK9 as post-transcriptional regulator of the amount of LDLRs in the liver is supported by the finding that gain of function mutations of PCSK9 in humans cause hypercholesterolemia, while loss of function mutations cause hypocholesterolemia, and respectively increase and reduce cardiovascular risk[10,36]. The gene discussed is PCSK9; the disease is Hypocholesterolemia.