STAG2 and Dravet syndrome: STAG2 and RAD21 have the higher mutation frequency than SMC1, SMC3 and NIPBL, with approximately 9.1–18.4% and 11.3–22.4% in ML-DS cases respectively (Nikolaev et al., 2013; Yoshida et al., 2013; Labuhn et al., 2019; Panferova et al., 2021).