Some MECP2 mutations may present a wide range of neuropsychiatric conditions including autism spectrum (Qiu, 2018), intellectual disability (Berger-Sweeney, 2011; Bassani et al., 2013), schizophrenia (Sweatt and Tamminga, 2016), depression, and cocaine addiction (Ausio, 2016). Here, MECP2 is linked to major depressive disorder.