The headline is so hyperbolic it's basically a lie. It becomes a little tricky because autism spectrum disorder is kind of a broad category. There are certain diseases that have clear genetic causes, other features to their phenotype besides just autism like features, but may share some aspects of autism spectrum disorder symptoms. So often these get lumped in with autism and patients with those disorders also get a diagnosis of autism spectrum disorder. For instance people with fragile x syndrome commonly get an autism diagnosis, but there's many other features to it as well.

This article stub if following a link at the end is referencing a gene called shank3. It's not involved in most people classified as having autism spectrum disorder. Mutations in shank3 causes a distinct disorder called Phelan-McDermid syndrome that causes severe intellectual disability, dysmorphic features, autism like features, motor issues, and abnormalities across multiple body systems. Shank3 mutations have also been linked with some cases of schizophrenia. A small minority of people with a diagnosis of autism spectrum disorder have shank3 mutations that may be responsible or pre disposing. So they are testing a gene therapy in mice engineered to have shank3 mutations. Which in humans can have a broad array of phenotypes depending on the mutation, many devastating and severe, some phenotypes of which include autism like features. This will not be very applicable to the vast majority of people classified as having an autism spectrum disorder.