Kalscheuer et al.[11] in 2003 provided the first report of mutations in the CDKL5 gene in two unrelated patients with infantile spasms and mental retardation due to two different balanced X-autosome translocations; since then, more than 80 patients with pathogenic mutations in this gene have been described [29]. This evidence concerns the gene CDKL5 and infantile spasms.