Mutations in JAG1 and NOTCH2 genes are responsible for Alagille syndrome (ALGS1 and ALGS2, respectively), an autosomal dominant disorder defined by a paucity of intrahepatic bile ducts, combined with cholestasis, cardiac disorders, skeletal abnormalities, ocular malformations and facial dysmorphisms. This evidence concerns the gene NOTCH2 and cholestasis.