Classic examples of this are Mendelian susceptibility to mycobacterial disease (MSMD), which results from impaired IFNγ-mediated immunity following exposure to mycobacterial species [58], and herpes simplex virus encephalitis (HSE) resulting from impaired TLR3-mediated anti-HSV1 immunity [59, 60]. The gene discussed is TLR3; the disease is herpes simplex encephalitis.