FIGURE 1 (22): ADH-1 comprises mutations within LDLR. There are six major classes of ADH-1, affecting: a) synthesis of LDLR; b) exit of mature LDLR from the endoplasmic reticulum; c) binding site of LDLR to apoB-100; d) endocytosis of LDLR-apoB-100 complex; and recycling of LDLR to the cell surface (not shown). ADH-2 comprises mutations in apoB that block the association of apoB-100 to LDLR. ADH-3 is due to GOF mutations of PCSK9, which reduce LDLR recycling and accelerate its lysosomal degradation. Adapted from Calandra et al. J. Lipid Research 2011; 52: 1885-926.