Washington: Scientists have offered new clues into the genetics underlying a chronic form of liver disease, called primary biliary cirrhosis, which can lead to transplant surgery for patients.The new study identified 15 genetic regions that affect a person`s risk of developing primary biliary cirrhosis, more than trebling the number of known genetic regions, which now stands at 22.The findings suggest that several key immune processes underlie susceptibility to primary biliary cirrhosis (PBC).Patients with primary biliary cirrhosis suffer irritation and swelling of the bile ducts of the liver – blocking the flow of bile, which normally aids digestion."To gain an insight into the causes of primary biliary cirrhosis we compared genetic data from patients and healthy volunteers and found 22 regions of the genome that differed significantly, 15 of which had not previously been identified," said Carl Anderson, from the Wellcome Trust Sanger Institute and one of the senior authors on the paper."By scrutinizing the genes within these regions we were able to identify biological pathways that appear to underpin the disease, thus prioritising these for future research and highlighting their potential for therapeutic intervention,” he said."This study is a key first step in our efforts to unravel the biological complexity of primary biliary cirrhosis and further research building on these results is already underway,” he added.The team found that many of the 15 new regions contain genes involved in regulation of the immune system, with three immune pathways particularly prominent."For clinicians involved in the management of primary biliary cirrhosis, this study is exciting because it provides new and meaningful insight into the biological origins of this condition," said George Mells, from the Academic Department of Medical Genetics at the University of Cambridge and a first author on the study.