We searched PubMed, EMBASE, and Cochrane databases for studies published up to January 2017 using the following key words: ["cytokine" OR "interleukin" OR "tumor necrosis factor alpha" OR "interferon-gamma" OR "single nucleotide polymorphism"] AND ["febrile seizure" OR "febrile convulsion"] AND ["pediatric" OR "infant" OR "child"].