INS and Rett syndrome: Moreover, pathways directly connected with ASD are: “Long term depression” that, together with “Long-term potentiation”, are the key regulators of long-lasting synaptic plasticity at the basis of learning and memory and whose impairment is involved in many brain disorders, including ASD [123,124]; “Insulin signalling pathway” promotes neuronal circuit development and maturation to an extent that, since its safety/preliminary efficacy for the treatment of Rett syndrome has emerged, clinical trials to ameliorate ASD symptoms are ongoing [125].