Notch signaling is also important in human liver development, as Alagille syndrome patients have mutations in Notch signaling components, such as Jagged1 [39, 40] and Notch2 [41], and the majority of patients display clinical manifestations of neonatal jaundice, cholestasis, and paucity of intrahepatic bile ducts [42]. Here, NOTCH2 is linked to Alagille syndrome.