"The reason behind the rise is probably a heightened awareness by parents, while a looser diagnostic tool might have discovered more people with the illness," HKU pediatrics professor Virginia Wong Chun-nei said.

Yesterday was the inaugural World Autism Awareness Day, as designated by the United Nations in December.

Autism, Wong said, involves symptoms such as impairment in social interaction and communication for children, as well as restricted interest and compulsivity.

"Autistic children usually cannot make eye contact, gesture like pointing at things, or smile, and they tend to like to stack or line things up, like toy cars," she said yesterday.

Wong said children could be diagnosed with the problem at the age of two. There is no medication to completely cure the disorder.

Many more boys are autistic than girls, with the boy-to-girl ratio for autism standing at 6.6 to 1, Wong said.

Wong also suggests parents conduct a CHAT-23 test, or Checklist for Autism in Toddlers, as early as possible.

"I think people should not mind being labeled autistic ... the more one denies, the tougher the road ahead," she said. "Well-known figures like Ludwig van Beethoven, Albert Einstein, Isaac Newton and George Orwell were all autistic."

Lattianna Wong Wang-kei, 23, was diagnosed with autism when he was two or three, but recovered when he was in Secondary Five.

"Even just studying was very difficult for me as I was dyslexic, I could not even fill in my own handbook. Not to mention being the subject of jokes of classmates," he said.

Wong, currently a student at the Chinese University's School of Continuing and Professional Studies, said his family's encouragement, as well as taking part in extracurricular activities helped him overcome the illness.

"For people who are autistic like myself, I hope you can face life positively, expand your vision while developing something you enjoy doing," he said.