In a multicenter randomized controlled trial, patients with chronic hepatitis C were randomly divided into two groups: PEG-IFN-α plus RBV and PEG-IFN-α plus RBV + vitamin D. The results showed that the vitamin D addition had no effect on SVR rates in treatment-naïve patients, regardless of the genotype [95]. Here, IFNA1 is linked to chronic hepatitis C virus infection.