We focused on immediate early genes and markers of plasticity (C-fos, Arc/Arg3.1, Bdnf), genes of the oxytocin/vasopressin system (Oxt, Avp, Oxtr, Avpr1a, Avpr1b) because of their key role in social behavior and evidences of altered function in Oprm1−/− mice9,11, autism gene candidates (Nlgn1, Foxp1, Crh) whose expression was dysregulated in this model9 and finally Grm4, encoding mGluR4 receptors whose activation relieves autistic symptoms9. The gene discussed is ARC; the disease is autism.