MECP2 transgenic mice recapitulate some of the core symptoms of MECP2 duplication syndrome, including social deficits. The cover illustrates that normalization of MeCP2 expression in the medial prefrontal cortex of the MECP2 duplication mouse model via CRISPR-Cas9 gene-editing reverses the social recognition deficit and mice perform social interactions normally. See pages 570–584. (Cover image provided by Dr. Yefei Li)