Decreased mRNA expression in the livers from WD patients was documented for ABCB11 (U = 27; N = 27; p = 0.019) and ABCG2 (U = 11; N = 27; p = 0.001), while BSEP (encoded by ABCB11 gene) and MRP2 (ABCC2) protein abundances were significantly lower [48% (U = 34; N = 27; p = 0.049) and 14% (U = 24; N = 27; p = 0.012)] of the mean value of the controls, respectively). This evidence concerns the gene ABCB11 and Wilson disease.