CDKL5 and hereditary disease: STXBP1 (13), CDKL5 (13), TSC2 (10), KCNQ2 (6), IRF2BPL (4), and TSC1 (4) were the most frequently implicated genes, which were responsible for 48.5% of the 103 patients with genetic disorders, while other causative genes were found in <3% respectively.