Montrealers find gene for top cause of blindness in newborns

Researchers in Montreal and the Netherlands have identified a gene behind the most common cause ofblindness among newborns, raising hopes that a treatment will some day be developed to partially restore vision.

Medical teams at McGill University Health Centre in Montreal and the University of Nijmegen in the Netherlands were able to identify the gene, CEP290, after testing a family in Valleyfield, Que., half of whom were blinded by thehereditary disorder Leber congenital amaurosis (LCA).

In subsequent testing, researchers found the mutated gene present in 25 per cent of patients with LCA,which affects about 10,000 young Canadians and causesthe cells in their eye to die or malfunction.

The discovery of CEP290, which is the ninth gene that has been tied to LCA, represents a major step toward understanding hereditary blindness, said Dr. Robert Koenekoop, the director of theMUHC's Ocular Genetics Centre in Montreal.

"I would say this is the single most important gene for congenital blindness just based on numbers, frequency and impact," said Koenekoop, who was part of the Montreal team.

Koenekoop added that each gene's discovery has been important because it offers information about how the retina works and how the disease occurs.

"We can now describe the genetic basis of hereditary blindness in babies in up to 75 per cent of cases and that's spectacular," he said.

The team's research, which was funded by the Foundation Fighting Blindness Canada, waspublished inthe September issue of the American Journal of Human Genetics.

Children with LCA often appear to haveeyes that jiggle in their sockets and have a hard time focusing on objects. The disorder affects one in 30,000 newborns and about150,000 people in total worldwide.

1st human trial of another LCA gene starts soon

The discovery of CEP290 moves researchers closer to developing gene therapy treatment that could partially restore their vision andalsoopens the possibility of prevention if combined with genetic screening of embryos, Konekoop said.

The first human gene replacement therapy trial for vision is slated to take place in Philadelphia in January on another LCA gene RPE65.

In animal studies, researchers have found 30 per cent of sight can be restored with gene therapy.

Gene's discovery thrills parents of blind toddler

Nadine Seed, whose young son was blinded byLCA, said she was delighted to hear of the discovery of the latest gene and hopes her son'sveil of darkness may one day be lifted.

Seed, who lives in Edmonton, gave her thanks to theeight Quebec siblings whoagreed to testingand helped the researchers track down the gene.

"I thank God that they came forward," Seed told the Canadian Press in a telephone interview.

Seed and her husband, Mike, were shocked when their son was diagnosed three years ago, at four months of age, with LCA. But theirdespair turned to hope after Koenekoop called this year to say the boyhad the CEP290 gene.

"It was the second-best group of news that I could ever hear in my whole life the first being that my son could see."