Notch-associated disorders include different types of severe disorders such as Alagille syndrome caused by mutations in both ligand JAG1 and receptor Notch2 and autosomal recessive spondylocostal dysostosis, caused by mutations in ligand DLL3, and many other members of the Notch-signaling pathway (Penton et al., 2012). Here, JAG1 is linked to Alagille syndrome.