At the time of this writing, there have been several conditional knockouts of Mecp2 that target different neuronal subtypes, each replicating a few aspects of the Mecp2 deletion phenotype: Sim1 conditional knockout mice are hyperphagic and become obese (Fyffe et al., 2008); mice with Mecp2 deleted from dopaminergic neurons develop some motor deficits (Samaco et al., 2009); and conditional knockout of Mecp2 from basal forebrain cholinergic neurons may result in decreased anxiety and impaired social interaction (Zhang et al., 2016). Here, SIM1 is linked to Anxiety.