Joanne Cheng shoots morning exercises at Cana Autistic School in Guangzhou, the first Chinese mainland public school for autistic children. Provided to China Daily

Cheng works on her fourth documentary A Child: Autistic Challenge to China. Gao Erqiang / China Daily

After women with bound feet and orphans in Shangri-La, documentary maker Joanne Cheng turns her attention to a special group of children on the mainland. Tiffany Tan reports.

Forty-something Chinese-American documentarian Joanne Cheng is getting ready to deliver her fourth baby before the end of the year. A Child: Autistic Challenge to China is slowly taking shape in the guest-cum-editing room of Cheng's apartment inside Beijing Foreign Studies University, where she teaches film and television.

China Daily caught up with her on a recent sunny Sunday afternoon, as she was reviewing raw video footage on Cana Autistic School in Guangzhou, the first Chinese mainland public school for autistic children.

"I'm trying to see everything with a fresh pair of eyes I look for things that move me," Cheng says from behind the editing console, explaining the meticulous process of trimming 72 hours of footage into an hour-long film. "This is why nobody's married here," she adds with a laugh.

Nearby, atop the quilt-covered single bed lie sheets of plain white writing paper, each scribbled with scene titles and sequence descriptions in a mix of English and Chinese. Cheng says this helps her get an overview of her material, which she began filming in the autumn of 2008.

She is still determining the film's storyline, but like her previous works - on women with bound feet (Golden Lotus), orphans in Shangri-La (Mama's Gold) and Americans' misconceptions about the Chinese (China Gold Rush) - A Child is going to be an intimate look at a group on the margins of society.

"This (autistic) population is an invisible one to many," says Cheng, a petite woman with a pretty smile and seemingly boundless energy. "They are physically fit and very handsome and pretty To the general public, they are not identifiable.

"Only when people spend some time with these kids do they discover that they do not mingle or react to communication signals."

A Child will also touch on the Chinese government's policies to help people with autism as well as the existing professional support for autistic communities, Cheng says.

There are some 2.37 million children aged 14 and below with autism on the mainland, according to estimates by the United States Center for Disease Control. According to the Ontario Adult Autism Research and Support Network, this figure represents approximately 2.8 percent of the global population with autism, a developmental disorder affecting physical, social and language skills. Experts say the numbers are just an estimate since many autistic people remain undiagnosed in much of the world.

Cheng, a Beijing native who migrated to the United States in 1988, and who prides herself on works that facilitate cross-cultural communication, is up-front that it was her 5-year-old niece who served as a catalyst for A Child.

"Making this film is an effort, to begin with, to help her," says the former CCTV reporter and host. "I had to do something because I could not take care of her on a daily basis, unlike my brother. I had to do something as an aunt. So I went around the world to search for information, trying to find, not necessarily a cure, but trying to understand the situation.

"I discovered she's one of so many other people. From a personal effort to help her, my mission became an effort to help, perhaps, I don't want to say the nation but, a very special population in the world."

Cheng also seems motivated by a desire to come to terms with a personal disappointment. "I've always wanted a child of my own. But because I was not able to have one, I put my hopes on this girl."

The filmmaker says when she hit her 40s, she tried twice to get pregnant through in vitro fertilization (IVF).

Now, Cheng is pouring her heart into teaching and filmmaking. Soon after she completes A Child, she says she'll start post-production on her very first feature film. Posters of her two upcoming films can already be seen hanging on the walls of her guestroom.

"I feel so pregnant," Cheng says with a grin.