The disease pathogenesis of HSE has long remained unclear, until the recent findings that inborn error of toll-like receptor 3 (TLR3) immunity may underlie the development of HSE in children with mutations in TLR3, UNC93B1, TRIF, TRAF3, and TBK1 (14). The gene discussed is UNC93B1; the disease is herpes simplex encephalitis.