Glaucoma
Another important eye disease is glaucoma, the leading cause of blindness worldwide. In glaucoma, fluid pressure inside the eyes slowly rises, damaging the optic nerve—the nerve that transmits visual information from the eye to the brain. There is no cure for the disease, but medications can lower eye pressure in glaucoma's early stages, thus slowing progression of the disease and helping to save vision. Glaucoma is inherited in about 50% of sufferers.
One of the world's leading glaucoma geneticists is Dr. Michael Walter. When he arrived at the University of Alberta in 1993, Dr. Walter began intensive research to identify the genes responsible for some severe types of childhood glaucoma. A major breakthrough in his lab was the identification and cloning of the FOXC1 gene, a mutation of which causes one form of early-onset glaucoma.
"But identifying genes and knowing what mutations cause glaucoma doesn't tell you how or why glaucoma happens," says Dr. Walter. "That's why my research has shifted in recent years. I'm interested in understanding what certain genes normally do, what happens when they mutate in glaucoma, and what we can do to prevent damage to the optic nerve."
Dr. Walter's research centres on two genes that regulate the functions of other genes. FOXC1, for example, probably affects about 2000 genes, not all of which are involved in glaucoma. When controller genes such as these mutate, their ability to regulate other genes is compromised—they might not activate a gene at the right time or to the right extent, or they might not turn it on at all.
"It's a cascade effect," says Dr. Walter. "While this might sound complicated—and it is—these pathways also open up opportunities for therapy. We may not be able to fix the transcription factor, but we may be able to intervene at a downstream point and fix other genes in the pathway so that the end result is no disease. While we can't do this right now, it illustrates why understanding the pathways through which genes function is so important."