Because autism is a "spectrum disorder" it has a range of affects on an individual. A few on the characteristics of autism are: difficulties with communication & social interaction, repetitive interests & activities, & unusual attachment to objects & routines.
Medical conditions, genes, & environment may place certain children at risk for autism spectrum disorders (which are more common among boys than girls). Autism starts when children are very young and is difficult to diagnose because there is no medical or blood test to confirm it. Similarly, there is no cure. Early detection & intervention through behavioral & educational therapy that is based on a child's individual challenges can lead to a functional life.
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Social interactions & relationships Symptoms may include:

Problems with speech & language comprehension are a common sign of the
autism Symptoms may include:

  • - Delay  in learning how to speak (after the age of 2) or doesn’t talk at
    all.
  •  - Speaking  in an abnormal tone of voice, or with an odd rhythm or
    pitch.
  • - Repeating words or phrases over and over without communicative intent.
  • - Trouble  starting a conversation or keeping it going.
  • - Difficulty  communicating needs or desires.
  • - Doesn’t  understand simple statements or questions.
  • - Taking  what is said too literally, missing humor, irony, and sarcasm.