Although studies using mouse models of Rett syndrome have proven to be key in identifying neurological phenotypes of the mutations and pinpointing the possible targets of MeCP2, they often involve mutations and/or manipulations affecting a large population of neurons and/or non-neuronal cells [11], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], thus making it difficult to differentiate between causality and compensatory effects. This evidence concerns the gene MECP2 and atypical Rett syndrome.