Autism stems from glitches in neurological development that cause sufferers to be socially impaired. Unable to interpret what people are expressing or to communicate how they feel, they typically become engrossed with specific objects instead or find comfort in repetitive behaviour and routine. But Lo, or Nang as he is affectionately known, is a rare autistic person who found a way to express himself.

'I like communicating with others through my clay art, which leads you into my world, and allows me to see the world of others,' he says.

Chow Yung-ping, CEO of the Arts Development Council, was 'stunned by the originality' of the 100 works displayed in Nang - New Art, New Genres. 'His art has a certain spiritual enlightenment. The symmetrical patterns and kaleidoscopic colours show amazing depth and discipline, which can only be achieved by his profound instinct,' Chow says. It's 'an achievement that reminds me of the saying that what God takes away from you, you receive something better.'

Even so, Lo and his family endured plenty of tough times before he found his way to clay.

'He did not say a word until he was four. We thought he was dumb,' says his sister, Sam Lo Wai-sum.

Although she's just a year older, Sam Lo has acted as Nang's link with the outside world since they were little.

'We went to the same primary school; because Nang could not communicate with his classmates he would scream when his emotions got beyond his control. I was often called to the principal's room to bail him out,' she recalls. 'Everybody avoided him. He had only himself to talk to.'

Nang was in Primary Three before doctors diagnosed his condition. Most people were ignorant about autism and few empathised about his condition.

People can be quite cruel, as his mother Wong Miu-hing has learned from painful experience.

'When Nang was little he broke something in a shop and the owner was furious. So I explained his condition and apologised. But he said I shouldn't take such a child out and that I should lock him up at home,' she says. 'At the time I was upset and asked myself why my boy was so different from others. But gradually I got to understand it and I am used to the unfriendly remarks about my boy.'

Because Nang didn't look any different from other children, Wong says, outsiders often blamed her for his odd behaviour and social ineptness. 'People [would] point fingers not at him but at me, saying I spoiled him or that I should keep him at home. But I ignored them and kept taking him out.'

Her husband could not accept Nang's disability either, so strains at home were eased considerably after they divorced three years ago.

The United Nations describes autism 'the fastest-growing serious developmental disability in the world' with an estimated 67 million autistic people across the globe, which is why it has marked April 2 as World Autism Awareness Day since 2008.

In Hong Kong, the official figure for people being treated for autism was 3,800 in 2009, but Francis Yu Sau-ying, founding chairman of welfare group Autism Hong Kong, suspects there are a lot more with the condition.

Using the US rate of one autistic person to 110 people, Yu says the actual number of autistic people in Hong Kong may be up to 70,000. That Chief Executive Donald Tsang Yam-kuen discussed autism in his policy address last year for the first time may be a sign the government is starting to recognise a need to devote resources to their care.

For Nang and his family, it has been a long and lonely road to discovering the 'key' that helped open him to the world.

But his sister says he displayed great interest in lines and patterns very early on. He particularly liked the floor plans included in property ads and often grabbed a copy whenever he came across them and use these to devise his own sketches.

'Unlike most kids, Nang didn't use the supplied patterns such as those in Lego or origami sets. He always created his own,' says Lo. 'He liked to take toy cars or planes apart and then put them back together in his own way.'

Nang rarely spoke and mainly concentrated on creating his own world. 'But we didn't know those were small acts of what people call art,' Lo says.

They discovered his gift by accident. He had been working a packer in a sheltered workshop run the New Life Psychiatric Rehabilitation Association for several years when its manager, Carmen Au Ka-man, introduced handicraft groups in 2005 to help raise their output and keep participants engaged.

Nang was put in a clay art group and stood out almost instantly.

'He went far beyond what we expected of the group,' says Nang's craft instructor, Lee Ying. 'Instead of following the model format, he created his own combinations of colours. Amazingly, he never repeats himself and produces one pattern after another in a way that I can never come close to.'

Recognising his exceptional talent, the workshop set up Nang with his own work space, tools and a variety of coloured clay.

Within two years, he was winning public recognition. He took first prize in the soft clay art category at the Hong Kong Abilympics 2007, which conferred a five-day tour to see clay art in Japan. It was the first time he had been on plane or travelled without his family. However, Nang brought his camera to record images that inspire him and an eagerness to view other clay creations.

He also had his cassette tapes - mostly YouTube downloads of his favourite 80s era commercials and television theme tunes that he listens to incessantly to keep out the disturbance of the outside world. That's not to say Nang is oblivious of what goes on around him.

'Although he doesn't say much, he's very sensitive to what he sees as injustice, especially bullying of the weak,' his mother says. 'Once he reprimanded a parent for disciplining a mischievous child on the street. And when Lehman Brothers went into meltdown, he became furious and condemned unscrupulous [bankers]. Sometimes I have to keep him from the news [to avoid upset] but he gets it on the internet instead.'

By the time Nang went on his second study tour (to Singapore in January), he was already an expert in clay craft, no longer camera-shy and ready to comment on the artwork he saw. And at his own exhibition, he was able to conduct demonstration sessions for the public (albeit with headphones on throughout).

'He felt anxious that people may not like his work,' Sam Lo says. 'So when the show was over and 25 of his works were sent for auction, he was very relieved and was very happy, although he did not show it.'

Lo reckons her brother seems to have matured since the exhibition.

'When I told him I would be moving out after my wedding in September, he told me not to worry as he would look after mum. I was very moved,' she says.

To Lee Ying, the changes started as soon as Nang found clay art.

'When he worked as a packer, he still made outbursts and got frustrated easily. But his behaviour changed after he picked up clay art. At first he was still sensitive about less positive comments, but now he can accept such advice. He also learned how to take care of himself, taking pleasure in photography and travelling around town.'

Whether Nang's success story can lead to similar breakthroughs for other autistic people remains to be seen. 'I don't think there is a formula for identifying the gift of an autistic person,' says Au.' All we can do is to expose them to various activities and observe carefully. It requires a lot of commitment, patience and flexibility from us to connect with their inner world.'

Still, the reward could be enormous. In the US, the lifetime societal cost of caring for an autistic person may be as much as US$3.2 million. With increasing self-confidence, Nang has been able to care for himself. And besides the HK$1,000 monthly stipend he receives from the New Life workshop, he gets additional revenue from auctions and sales of his clay craft such as picture frames.

'The government has every reason to devote resources to autistic people,' says Yu of Autism Hong Kong. 'As Nang shows, this can transform what was originally a social burden to social capital. It has everything to gain, and full of happy surprises and possibly uncovering more beautiful minds, too.'