STXBP1 and early-infantile DEE: Responder rate of Ohtahara syndrome patients with KCNQ2 or STXBP1 mutations showed a significantly better response to KD after 3 months compared to Ohtahara syndrome patients without KCNQ2 or STXBP1 mutations (88.9 vs. 37.5%, p = 0.043).