Furthermore, a recent work in MECP2-null mice, which model Rett syndrome, an X-linked autism spectrum disorder, has provided one of the first causal links between microglial alterations and psychiatric disturbances: the authors succeeded in the mitigation of Rett syndrome-like symptoms by supplying wild-type microglia through bone marrow transplantation or genetic rescue in MECP2-null mice (Derecki et al., 2012). Here, MECP2 is linked to autism spectrum disorder.