Research shows that early diagnosis of and interventions for autism are more likely to have major long-term positive effects on symptoms and later skills.1,2,3,4,5 Autism spectrum disorder (ASD) can sometimes be diagnosed in children before they are 2 years of age. Some children with ASD whose development seems typical up to that point begin to regress just before or sometime during age 2 years.6| https://www.nichd.nih.gov/