PCSK9 and familial hypercholesterolemia: PCSK9 patients had significant higher serum total cholesterol concentrations (13.6 ± 2.9 versus 9.6 ± 1.6 mmol/L; P = 0.004) [103] and appeared to be more resistant to statin therapy compared to heterozygous familial hypercholesterolemia patients with known mutations in LDLR.