LDLR and homozygous familial hypercholesterolemia: <h4>Background</h4>Homozygous familial hypercholesterolemia (HoFH) is a rare inherited disorder of lipoprotein metabolism caused by pathogenic variants in both alleles of key low-density lipoprotein receptor (LDLR)-mediated pathway genes, resulting in very high LDL cholesterol (LDL-C) levels from birth.