Upon viral infection, pattern recognition receptors (PRRs) like the Toll-like receptors (TLRs) and retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5) sense viral nucleic acids, activating downstream signaling factors that ultimately result in the production of IFN-I. This evidence concerns the gene IFIH1 and viral infectious disease.