Genetic mutations in TCF4 have been reported in neurological disorders, including Fuchs’s corneal dystrophy [42], Pitt–Hopkins syndrome [43], and schizophrenia [44], as well as non-neurological diseases, including primary sclerosing cholangitis [45] and sporadic Sonic Hedgehog-associated medulloblastoma (SHH MB) [46]. The gene discussed is TCF4; the disease is sclerosing cholangitis.