As it is caused by loss-of-function mutations in the gene encoding methyl-CpG binding protein 2 (MECP2), Rett syndrome is modeled using variations of Mecp2-deficient mice. The specific deletion of Mecp2 in murine microglial cells triggers an overproduction of glutamate, altering neuronal morphology and impeding the formation of synapses (72). The gene discussed is MECP2; the disease is atypical Rett syndrome.