We identified in one case (S557) with unclassified EEE, two de novo novel variants; SCN8A (NM_014191) c.5615G > A/p.R1872Q and KCNMA1 (NM_001014797) c.3488A > G/p.N1163S. Here, KCNMA1 is linked to eastern equine encephalitis.