The HCV UpA dinucleotide frequency was significantly associated with the IFNL4 SNP rs12979860 genotypes; interestingly, ribonuclease L (RNase-L), an ISG that cleaves viral RNA to control viral infections in animals (Ding and Voinnet, 2007), targets both UpA and UpU dinucleotides (Wreschner et al., 1981). The gene discussed is IFNL4; the disease is viral infectious disease.