Nevertheless, up to 60% of the presumed viral encephalitis cases remain unexplained due to the failure of conventional laboratory techniques to detect an infectious agent.[30] Three cases of bilateral symmetrical bilateral claustrum lesions caused by viral infection have been reported, including 2 cases of HSV,[31,32] and 1 case of mumps virus.[33] In our study, IgM of HSV and the other uncommon virus was not tested. The gene discussed is CD40LG; the disease is viral encephalitis.