Mouse Mecp2 represses transcription from the Crh gene promoter, encoding corticotropin-release hormone (corticoliberin). Crh is overexpressed in Mecp2 knockout mice, a mouse model of Rett syndrome, which results in enhanced anxiety and stress-induced corticosterone release (McGill et al. 2006). Surprisingly, Crh is also overexpressed in the mouse model of the Mecp2 duplication syndrome (Samaco et al. 2012).