Cell signalling dysfunction in mTOR signalling pathway leading to syndromic and idiopathic autism. Pictorial illustration of mutations in specific genes FMRP, NF1, PTEN, and TSC1/TSC2 that lead to loss/reduction of function causing syndromic autism of fragile X syndrome, neurofibromatosis type 1, PTEN Hamartoma tumour syndrome, and tuberous sclerosis complex, respectively. mTORC1 stimulation leads to activation of 4EBP which hinders the translation or activation of P70S6K that triggers translation initiation. Truncated protein synthesis by these down regulators during translation leads to hyperactivation, causing autism spectrum disorder or hypoactivation of protein synthesis that leads to idiopathic autism.