MECP2 and neonatal encephalopathy: Males with MECP2 mutations fall into four categories: severe neonatal encephalopathy and infantile death; classical RTT; less severe neuropsychiatric symptoms; MECP2 duplication syndrome (Imessaoudene et al., 2001; Jülich, Horn, Burfeind, Erler, & Auber, 2009; Kyle, Vashi, & Justice, 2018; Meloni et al., 2000; Ramocki et al., 2009; Schwartzman, Bernardino, Nishimura, Gomes, & Zatz, 2001; Topҫu et al., 2002; Van Esch et al., 2005; Zeev et al., 2002; Table 4).