They are well-known for secreting large amounts of type I interferons (IFNs) in response to viral infection (2); pDCs produce 10–100-fold more type I IFN than other immune cells following their recognition of unmethylated CpG dinucleotides and double-stranded RNA synthesized by many viruses through toll like receptor 7 (TLR7) and TLR9, respectively (3). The gene discussed is TLR7; the disease is viral infectious disease.