Increasing plasma bile acid levels through the feedback system in patients with PBC gives rise to the higher expression of fibroblast growth factor 19 (FGF19) that activates the hepatic membrane receptor FGFR4 by suppressing the synthesis of bile acids, which contributes to the development of hypercholesterolemia [25,26,27,28]. This evidence concerns the gene FGF19 and primary biliary cholangitis.