Autism spectrum disorder (ASD) is a complex neurodevelopmental monogenic disorder with a robust impact in genetics. Idiopathic autism could be defined as a type of autism which does not have a specific causative agent. Among the signalling cascades, mTOR signalling pathway has a pivotal role not just in cell cycle, but also in protein synthesis and regulates the brain homeostasis in ASD patients. The present review highlights the underlying mechanism and the role of altered signalling cascades as a triggering factor in the onset of idiopathic autism. Further, the review discusses how the distorted mTOR signalling pathway, stimulates truncated translation in the neuronal cells and leads to downregulation of protein synthesis at the dendritic spines of the brain. The review concludes by suggesting downstream regulators like p70S6K, eIF4B, eIF4E of mTOR signalling pathway as a promising therapeutic target in idiopathic autistic individuals.