RELN and autism: Pharmacological manipulation of the serotonergic system during very early brain development altered reelin expression levels [29] which might explain indirect effects of the serotonergic system on the late stages of embryonic cortical development mediated by reelin [30–32].There is evidence that the serotonergic systems as well as reelin levels are dysregulated in several neurological disorders such as autism and schizophrenia[33–38].