Additional Study Information: This is a 20-year study of adult patients with Primary Sclerosing Cholangitis (PSC). The purpose of this research study is to evaluate PSC throughout North America, as PSC is a rare disease, and not enough information is available for patients, clinicians, and researchers to help guide medical decisions and to help find new treatment options. Participants in this study agree to have information from their medical record entered into a PSC database maintained by Yale University, such as the date of diagnosis, whether they have colitis, and the results of any medical tests. Subjects will also have the option to provide blood samples for research. Approximately 2000 subjects are expected to be enrolled across all sites.