Correcting deregulated Fxyd1 expression rescues deficits in neuronal arborization and potassium homeostasis in MeCP2 deficient male mice.

•Mutations in the MECP2 gene are responsible for most cases of Rett syndrome (RTT).•Neuronal arborization is reduced in both human patients and mouse models of RTT.•Overexpression of a protein termed FXYD1 is involved in the neuropathology of RTT.•Normalizing Fxyd1 levels in RTT mouse restores neuronal arborization.•Normalizing Fxyd1 levels restores deficient Na-K exchange across the cell membrane.