In this line, other factors that lie within the MECP2 network have been associated with PTSD in a sex-specific manner across rodents and people (e.g. FKBP5, HDAC4) [72, 73] Furthermore, it is important to underline that developmental sex differences in MECP2 expression and its contribution to the emergence of sex dimorphisms have been previously acknowledged [37, 38]. Here, HDAC4 is linked to post-traumatic stress disorder.