MECP2 and Rett syndrome: 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).