title: Increased prevalence of primary sclerosing cholangitis among first-degree relatives.
abstract: OBJECTIVE
  The aim of the present study was to investigate the familial occurrence of autoimmune diseases in a large group of patients with primary sclerosing cholangitis (PSC).
  
  
  METHODS
  All patients with PSC treated at Huddinge University Hospital between 1984 and 1999 were included (n=145). For every patient with PSC and inflammatory bowel disease (IBD) (n=126) we randomly selected a control patient with IBD (n=126), matched for age, sex and type of IBD. A questionnaire comprising information about autoimmune diseases among first-degree relatives was answered by all patients and controls.
  
  
  RESULTS
  We identified 22 index cases with PSC from 21 families with a first-degree relative with either chronic liver disease and/or IBD. Five patients with PSC had a first-degree relative with PSC (3.4%). The prevalence of PSC among first-degree relatives was 0.7% (5/717). In siblings the prevalence was 1.5% (4/269). The prevalence of first-degree relatives with autoimmune diseases outside the liver was similar in PSC patients and controls.
  
  
  CONCLUSIONS
  First-degree relatives of patients with PSC have a PSC prevalence of 0.7%. This represents a nearly 100-fold increased risk of developing PSC compared with the general population, supporting the hypothesis that genetic factors are of importance for development of PSC.
authors.affiliation: Department of Gastroenterology and Hepatology, Karolinska University Hospital, Huddinge, Karolinska Institutet, Stockholm, 141 86 Huddinge, Sweden. annika.bergquist@medhs.ki.se
authors.forename: Annika
authors.initials: A
authors.lastname: Bergquist
authors.forename: Greger
authors.initials: G
authors.lastname: Lindberg
authors.forename: Susanne
authors.initials: S
authors.lastname: Saarinen
authors.forename: Ulrika
authors.initials: U
authors.lastname: Broomé
mesh_terms: D001327:Autoimmune Diseases / Q000453:epidemiology; D015209:Cholangitis, Sclerosing / Q000453:epidemiology* / Q000235:genetics*; D005190:Family; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000453:epidemiology / Q000235:genetics; D008107:Liver Diseases / Q000453:epidemiology / Q000235:genetics; D008297:Male; D009679:Nuclear Family; D015995:Prevalence; D011795:Surveys and Questionnaires