People with autism often don't respond to others' emotions. They may not realize how their behavior affects others. They find it hard to interpret others' tone of voice or facial expressions. Children with autism often speak later than other children and have hearing problems. They may also rock, twirl their hair, or bang their heads over and over again. People with autism also don't feel pain as vividly as others. They may have an abnormal response to sounds or touch.

You should have your child assessed for autism right away if any of these symptoms are present. Other behaviors that should raise concerns include:

• Possible deafness, or deafness that comes and goes
• The child used to speak but now does not
• The child doesn't smile when smiled at
• The child throws intense temper tantrums
• The child walks on his or her toes

A number of genes appear to play a role in autism, as do environmental factors. Research has found brain abnormalities in people with autism. Neurons in the cerebellum, amygdala, hippocampus, septum, and mamillary bodies of autistic people are smaller than normal and have stunted nerve fibers. These changes may mean that something interfered with brain development of the fetus. Other studies have found problems with the signaling molecules in the brain of those with autism. Other disorders, including Tourette syndrome, learning disabilities, and attention deficit disorder, often occur with autism but don't cause it. About a third of children with autism eventually develop epilepsy.

Although some parents believe that the measles/mumps/rubella vaccine caused their child's autism, no scientific proof has been found to back this up. The symptoms of autism often appear around the same time as the MMR vaccine is given. But that doesn't mean the vaccine has caused the autism. There is no scientific proof that any vaccine or combination of vaccines causes autism.

Autism has no cure. Behavioral therapy and medicine may help ease symptoms, however. In behavioral therapy, therapists work one-on-one with children to help them develop social and language skills. The earlier a child is helped with this therapy, the better the outcome. Medicine may be prescribed to ease troublesome behavior or other symptoms of autism. The medicine affects the levels of signaling chemicals such as serotonin in the brain.