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.