It is well established that autism tends to run in families but this is one of the first studies to indicate that epigenetic changes may be involved in increasing the risk of having a child who develops autism.

London - Some children diagnosed with autism at a young age later grow out of it, psychologists say, in a discovery that challenges the established view of the condition as a permanent disorder of social functioning with no cure.

If the finding is confirmed, identifying what helped those children who have made the transition from “autistic” to functioning like their peers could point the way to effective therapies.

An estimated 600,000 people in Britain are affected by autistic spectrum disorders. Sufferers have difficulty reading social situations and responding appropriately. The condition ranges from the mild to the severe, and has long been thought incurable.

Now researchers funded by the US National Institutes of Health say that view may have to be reassessed. The researchers identified 34 children and young adults ranging in age from eight to 21 who were considered to be on a par with their peers but had earlier been diagnosed with an autistic spectrum disorder.

In each case, the researchers carefully documented the earlier diagnosis. They compared the children today with a second group, matched for age and sex, who had been diagnosed with high-functioning autism - showing expert skills such as in drawing or mathematics - and with a third group of children whose development was unaffected.

The children are now being studied further to see if there have been changes in brain function or whether they still have subtle social deficits.

The researchers note that the children who appeared to have grown out of autism had a relatively mild form of the condition and a slightly higher IQ than those with high-functioning autism.

Deborah Fein of the University of Connecticut, who led the study published in the Journal of Child Psychology and Psychiatry, said: “All children with autistic spectrum disorders are capable of making progress with intensive therapy, but with our current state of knowledge most do not achieve the kind of optimal outcome that we are studying.”

Dr Judith Gould of the National Autistic Society urged caution. “This study is looking at a small sample of high-functioning people with autism and we would urge people not to jump to conclusions about the nature and complexity of autism, as well its longevity,” she said. “This research acknowledges that a diagnosis is not usually lost over time.” - The Independent