Scientists develop new potential cure for rare eye disease

Success in mouse model is first instance of drug reversing a congenital deformity

University of British Columbia and Vancouver Coastal Health scientists have developed a potential cure for a rare eye disease, showing for the first time that a drug can repair a birth defect.

They formulated the drug Ataluren into eye drops, and found that it consistently restored normal vision in mice who had aniridia (ANN-uh-ridee- uh), a condition that severely limits the vision of about 5,000 people in North America. A small clinical trial with children and teens is expected to begin next year in Vancouver, the U.S. and the U.K.

Aniridia is caused by the presence of a "nonsense mutation" - an extra "stop sign" on the gene that interrupts production of a protein crucial for eye development. Aniridia patients don't have an iris (the coloured ring around the pupil), and suffer many other eye abnormalities.

Ataluren is believed to have the power to override the extra stop sign, thus allowing the protein to be made. The UBC-VCH scientists initially thought the drug would work only in utero - giving it to a pregnant mother to prevent aniridia from ever arising in her fetus. But then they gave their specially formulated Ataluren eye drops, which they call START, to two-week-old mice with aniridia, and found that it actually reversed the damage they had been born with.

"We were amazed to see how malleable the eye is after birth," said Cheryl Gregory-Evans, associate professor of ophthalmology and visual sciences and a neurobiologist at the Vancouver Coastal Health Research Institute. "This holds promise for treating other eye conditions caused by nonsense mutations, including some types of macular degeneration. And if it reverses damage in the eye, it raises the possibility of a cure for other congenital disorders. The challenge is getting it to the right place at the right time."