Among PRRs, the endosomal TLRs including TLR3, TLR7/8 and TLR9, and cytosolic RLRs including retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated gene 5 (MDA5) play important roles in sensing viral RNA during viral infection (7, 9–11). The gene discussed is TLR7; the disease is viral infectious disease.