Researchers at the University of Toronto are working towards a genetic treatment for symptoms of Usher syndrome, a rare disorder that leaves newborns with profound hearing loss and gradually robs them of their vision.
Vincent Tropepe (photo by Diana Tyzko)
Led by Vincent Tropepe, a professor in the department of cell and systems biology in the Faculty of Arts & Science, the research into Usher syndrome type 1F (Usher 1F) suggests gene therapy may be able to correct the vision loss (the hearing loss can be alleviated with electronic cochlear implants).
Tropepe says the work is focused on determining how specific gene mutations affect the shape and integrity of photoreceptors, the light sensing cells in the retina.
"We think that in Usher 1F photoreceptors do not mature properly during development and the shape of their outer segment, the part of the cell that captures photons of light, is defective and often detaches from the rest of the cell," he says.
"Photoreceptors naturally repair their outer segments because of the 'wear-and-tear' in processing light. We think we could correct the gene and piggyback on the eye's natural ability to recreate the photoreceptor membranes to restore their shape and even regrow their outer segments."
Tropepe and his team recently received a $50,000 funding boost for their work from the Usher 1F Collaborative, a U.S.-based non-profit. The additinoal support came ahead of Usher syndrome Awareness Day on Sept. 18.
"Funding like the donation from the collaborative and also from Fighting Blindness Canada enables me to hire great trainees so I can start tackling this research from multiple directions in parallel," Tropepe says.
Scientists have identified three types of Usher syndrome based on the degree of hearing and vision loss, with Usher 1F being the most severe. In the United States and Canada, about four in every 100,000 newborns have Usher syndrome.
There is currently no cure.
For thousands of people born with Usher 1 and who are now gradually losing their sight, time is of the essence says Sari Springer, director of the collaborative, whose two nieces are among those living with the disorder.
One niece recently started a master's degree at American University in Washington, D.C. and the other is a University College London graduate and former Peace Corps volunteer with a successful career in the non-profit sector. Both are growing anxious about their advancing vision loss, says Springer, a U of T alumna who graduated in 1986 with a bachelor of arts in sociology as a member of University College.
At left: Rachel and Jessica Chaikof are losing their vision to Usher 1F. At right: Sari Springer, director of the Usher 1F Collaborative (photos courtesy of Rachel Chaikof and Littler)
"Vince's research is hugely important because it's focused on gene therapy and he's making enormous strides. We just need to get this across the finish line to save the sight of these young kids and adults," Springer says.
"The science says by the time they're in their 40s or 50s, they won't have any vision left. Vince is working at lightning speed to find the cure, but every day that passes is another potential day of more sight loss."
Amanda Miles (photo by Emily Dong)
Tropepe is working with research scientist and PhD student Amanda Miles, an alumna who graduated with her honours bachelor of science in cellular and molecular biology in 2014 as a member of University College.
He hopes to add up to two post-doctoral researchers with the new funding from the collaborative. He is also appealing for more help to speed progress.
"Really, what we need is a small team of people. When you have those sorts of resources, you can start to add to the excellent people we already have working on this," says Tropepe, who feels there are several other promising research threads like drug treatments that may prove useful in tandem with the gene therapy.
Miles says the Usher 1F research project - only a few years old - started with a discussion between her, Tropepe and Andrew Emili, a former molecular genetics professor at U of T who is now at Boston University.
"It's a really great example of how the U of T research community fosters collaborative discussion," says Miles.
U of T students living with a disability can rely on a world class network of support services, adds Springer, a lawyer who advises the university on disability issues.
"I've worked extensively with the University of Toronto Accessibility Services office and they are an incredibly passionate and dedicated group of individuals," says Springer.
"I come at it from the heart, because of my two nieces. I understand what it means to be able to succeed in university and how difficult that is without the assistance of such a highly accomplished accessibility services team."
