Autism is medically called an autism spectrum disorder and ranges from mild Asperger’s syndrome to very severe ones, such as Rett syndrome and Heller syndrome are a spectrum of autism. Asperger’s syndrome and common autism disorders do not affect a child’s life expectancy. But in the case of Rett syndrome, Heller syndrome and other neurodegenerative disorders, which are very serious neurological disorders, the symptoms are very similar to autism, also manifesting as intellectual regression, poor speech development, isolation, inability to interact with others, stereotypical behavior, and very easily confused with autism and Asperger’s syndrome. These two serious neurological disorders have now been removed from autism. These two disorders affect the child’s life expectancy. Other disorders such as mild autism spectrum disorders, or autism that exclude neurological disorders do not affect the child’s life expectancy.