GRM1 and autism: The striking effects of genetic reduction of Adcy1 on both ERK1/2 activity and autism-related behaviour in Fmr1 KO mice support the hypothesis that exaggerated ERK1/2 signalling significantly contributes to the autism-associated symptoms, which encourages future investigation in other autism models that shares common abnormality in mGluR1/5 and ERK1/2.