The mystery of primary biliary cirrhosis in British Columbia's First Nations people.

Abstract

OBJECTIVES: Primary biliary cirrhosis (PBC) is a rare chronic, progressive liver disorder leading to transplantation or death, with a known autoimmune basis. Although it has been estimated to have a prevalence of between 2-5 cases per 100,000 worldwide, it is not rare in British Columbia's (BC) First Nations (FN) peoples, where it is the leading indication for liver transplant in that population. A study of indications for liver transplant from 1989 to 1998 demonstrated that although just 3.9% of the population of BC is of FN descent, 25% of those requiring transplantation for PBC were of FN descent. From this, it can be calculated that PBC is about 8 times more common than in the non-native population. METHODS: We studied the prevalence of PCB on Vancouver Island, where about 50% of the cases on the transplant Society List are reported. RESULTS AND DISCUSSION: As with many autoimmune diseases, PBC affects women predominantly. Genetic predisposition and environmental factors are thought to contribute to the development of PBC. A strong genetic component is postulated in the BC population where 6 affected individuals are all related through common great grandparents. Nonetheless, both genetic and environmental components are being explored in this unique population.