STXBP1 and Neurodevelopmental delay: De novo heterozygous mutations in STXBP1 can cause some of the most severe forms of NDD + E, such as Ohtahara syndrome (Saitsu et al., 2010), West syndrome (Deprez et al., 2010), Lennox‐Gastaut syndrome (Allen et al., 2013), Dravet syndrome (Carvill et al., 2014) and other types of early onset NDD + E (Stamberger et al., 2016).