Scientists have discovered a gene that interferes with the clearance of hepatitis C virus infection. They also identified an inherited variant within this gene, Interferon Lambda 4 (IFNL4), that predicts how people respond to treatment for hepatitis C infection. The results of this study, by investigators at the National Cancer Institute (NCI), part of the NIH, and their collaborators at NIH and other institutions, were published online in Nature Genetics on Jan. 6, 2013.