LDLR and familial hypercholesterolemia: The LDL receptor-deficient mouse (Ldlr−/− mouse), which was generated as a model of homozygous familial hypercholesterolemia (caused by LDL receptor mutations in humans), on the other hand, exhibits an increase primarily in LDL-cholesterol when fed a chow diet, reflecting impaired clearance of LDL through hepatic LDL receptors (64).