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]. The gene discussed is FGF19; the disease is Hypercholesterolemia.