Genetic and familial considerations of primary biliary cirrhosis

The genetic basis of human autoimmune diseases is receiving increasing attention. Primary biliary cirrhosis (PBC) is a model autoimmune disease reflective of other organ-specific autoimmune pathology. PBC is an enigmatic autoimmune disease that predominantly affects women and leads to destruction of intrahepatic bile ducts. The serological hallmark of this disease is characterized by antimitochondrial antibodies that specifically react with the E2 components of 2-oxodehydrogenase enzymes, including PDC-E2. There are no clear major histocompatibility complex associations with the development of PBC, despite the observation that first-degree relations of index patients with PBC have a 4-6% prevalence of development of PBC. This risk factor is comparable or higher than any other human autoimmune disease and suggests that a genome-wide approach towards dissection of genetic associations would lead to valuable new insights. In this review, we place these concepts in perspective and highlight in particular the genetic associations in PBC and the importance of studying siblings with PBC who are concordant for disease.