Abstract
Human leukocyte antigen (HLA)-identical twin sisters with chronic liver disease were evaluated. Both had a childhood history of transient jaundice suggestive of a possible infectious cause. Subsequent studies in both siblings at age 51 years revealed antimitochondrial antibody-positive primary biliary cirrhosis. This report documents HLA-identical twins with primary biliary cirrhosis, providing added evidence for a genetically determined abnormal immune response in this liver disorder, possibly to a specific viral or other environmental factor.