What is the difference between autism and a mental handicap?

Different diagnoses: 35-65% of people with Autistic Spectrum Disorder (ASD) - observable deficits in social communication & social reciprocity + stereotypical movements or narrow, restricted areas of interest - also have intellectual disability (ID) , measured cognitive & adaptive abilities < 70 before age 18. Many Neurodevelopmental Disorders with ID do not have ASD in their Neurobehavioral profile.