MECP2 and atypical Rett syndrome: Transcriptome analysis was carried out on microglia from control female mice and heterozygous female mice carrying one Mecp2-null allele—a mouse model of Rett syndrome—at two time points; 5 weeks, prior to the onset of neurological symptoms (pre-phenotypic) and 24 weeks, after the development of neurological symptoms (phenotypic).