Importantly, MECP2 mutations which both increase (e.g., duplication) and decrease (e.g., loss-of-function) its function are strongly implicated in neurodevelopmental disorders, including ASD and RTT (Carney et al., 2003; Samaco, 2004; Van Esch et al., 2005; Ramocki et al., 2010; Wang et al., 2016; Wen et al., 2017). Here, MECP2 is linked to neurodevelopmental disorder.