Familial occurrence of primary sclerosing cholangitis and ulcerative colitis.

Members of three families had primary sclerosing cholangitis and chronic ulcerative colitis. In each family, two siblings were affected; in one instance, they were twin brothers. All six individuals had primary sclerosing cholangitis and five also had ulcerative colitis. These cases represent the first reported instances of the familial occurrence of both primary sclerosing cholangitis and chronic ulcerative colitis; illustrate the typical clinical, laboratory, radiologic, and pathological features of primary sclerosing cholangitis; and support the hypothesis that genetic factors may play a role in the etiology of this obscure disorder.