OTTAWA - Families who have battled the Ontario government and school boards for years over treatment for children with autism said Thursday they'll seek legal advice on where to go next after the country's top court denied them a hearing.

In a decision released without comment, the Supreme Court of Canada refused permission for the families to appeal earlier rulings that put strict limits on their lawsuit.

The families said they were disappointed and would meet with their lawyers in the "coming days to determine next steps."

"I don't know that I feel that I have a choice," said Taline Sagharian, whose 12-year-old son Christopher has autism.

"This is my son and his rights and I feel that I have to stand up for him and for other children like him."

The five families say children with autism are suffering discrimination because the province and school boards fail to provide expensive therapies for the kids in public schools.

"Obviously, the court's decision today was a letdown for us," Sagharian said.

"For almost a decade now, families of children with autism have continued to face an impossible choice between prohibitively expensive private autism programs and an unresponsive public school system."

In 2007, Ontario Superior Court threw out several of the key claims brought by the families at a preliminary stage.

The provincial Court of Appeal ruled earlier this year that some of the claims could proceed, but only after they are drastically reworked.

"We do have some (options), and I don't know how many, other pieces of the case left, that we can go back to the Superior Court for," Sagharian said.

The five families are trying to sue the government and the boards for negligence and damages, accusing them of failing to provide or properly fund the specialized autism therapies - known as intensive behavioural intervention (IBI) and applied behaviour analysis (ABA) - in schools.

The therapies for autism, a poorly understood neurological condition that causes developmental disability and behaviour problems, can cost between $30,000 to $80,000 a year for each child.

The parents, who say they are forced to go to financial "extremes," filed a $1.25-billion lawsuit in 2004.