Most children with autism spectrum disorder show developmental differences when they are very young, especially in social and language skills. They usually crawl, sit, and walk on time, so the more subtle social differences don’t get noticed. Here are some examples of social differences:
Not making eye contact with others  Not cuddling like other children  Not smiling back at others  Extreme interest in a particular item or activity  Repetitive actions  Frustration or anger at changes in routine  Not responding to his or her name  Tuning others out
Pediatricians now routinely screen for autism at 18 and 24 months.