By Briar Sexton, MD
Aniridia is a genetic eye disease that is present at birth. It is a panocular condition causing lack of or poor development of the cornea, fovea, iris and optic nerve. It also causes glaucoma, nystagmus, dry eye and cataracts. Individuals born with aniridia generally have vision between 20/80 and 20/200.
The genetic fault in aniridia is a nonsense mutation: effectively there is a stop sign or “stop codon” where there should be a green light. The result is a shortened protein that doesn’t function properly and leads to abnormal development of the eye in utero.
Ataluren is a commercially available drug that identifies the false stop sign and enables manufacture of the complete protein. It is already being used for diseases like muscular dystrophy and cystic fibrosis. Dr. Gregory-Evans posited that if Ataluren could be delivered to the eye it might help the eyes of newborn mice to develop more normally.
Her lab’s initial attempts were unsuccessful. The Ataluren drops did not dissolve and reach the back of the eye and they irritated the eyes of the mice. Her lab then pioneered a special formulation of Ataluren that dissolved and did not irritate. Mice that were born with abnormally developed eyes experienced a reversal of the damage with Ataluren treatment.
Recruitment for the first clinical trial in humans is currently underway. If successful, this treatment may help with other retinal diseases including Retinitis Pigmentosa and even some types of macular degeneration. The global scientific community is watching with keen interest to see the results of the Canadian trial and Canada’s philanthropic community is interested as well. Both CNIB and the Foundation Fighting Blindness fund Dr. Gregory-Evans’ laboratory.