Autism spectrum disorder (ASD) can look different in different people. It’s a developmental disability that affects the way people communicate, behave, or interact with others. There’s no single cause for it, and symptoms can be very mild or very severe.

Some children who are on the spectrum start showing signs as young as a few months old. Others seem to have normal development for the first few months or years of their lives and then they start showing symptoms.

But up to half of parents of children with ASD noticed issues by the time their child reached 12 months, and between 80% and 90% noticed problems by 2 years. Children with ASD will have symptoms throughout their lives, but it’s possible for them to get better as they get older.

The autism spectrum is very wide. Some people might have very noticeable issues, others might not. The common thread is differences in social skills, communication, and behavior compared with people who aren’t on the spectrum.