ABCG5 and Wilson disease: Next, we detected the mRNA levels of genes associated with cholesterol metabolic homeostasis, including biosynthesis (Hmgcr, Hmgcs, and Srebp2), transport (Sr-b1, Abca1, and Abca9), and secretion (Abcg5, Abcg8, and Cyp7a1) in the liver of WD-fed ALKO and LKO mice, and we found that the mRNA level of Abca1 significantly decreased and Sr-b1 significantly increased in ALKO liver tissues compared with LKO mice (Figure 2C and Supplemental Figure 2B).