Gene Discovery Ends Miami Family’s Long Search

MIAMI - It took 20 years, but a Miami family finally knows why three of their four children are blind. A University of Miami study identified a gene responsible for a condition that could lead to a loss of vision. [audio:|titles=UMiamigene|artists=Lhee]

Daria Zawadzki remembers the night when she drove into oncoming traffic… because she couldn’t see the cars.

"And it was pretty miraculous… that I wasn’t like killed in a car accident. And I came home and said to my parents, ‘Something is… something is definitely wrong,'" Zawadzki said.

Soon after, a doctor told her she had retinitis pigmentosa – a condition that could lead to blindness.

"He basically pulled out a book and said, ‘This is the retina with this disease. This is what you have. You’re going blind. There’s nothing you can do… nothing you can ever do,’" Zawadzki said.

Her younger brother and older sister were diagnosed with the condition too. Now, twenty years later, researchers at the University of Miami have found the gene that caused three out of the four children in Daria’s family to lose their sight.

Scientists used a new DNA-sequencing technology to find the gene, and they confirmed the discovery using zebrafish. When they manipulated the gene, the fish became partially blind.

Ophthalmologist Byron Lam remembers when he and his fellow researchers shut off the lights and realized the fish couldn’t see.

"When we turned the lights off, they didn’t move at all," Lam said. "But then we also went ahead and tested to see they can actually move normally under other circumstances."

Over 50 genes have been discovered linked to retinitis pigmentosa. But University of Miami researcher Stephan Zuchner said this gene is connected to a new pathway. He thinks the discovery opens the door to possible therapies, like inserting a copy of a “normal” gene in a person’s DNA to make up for the defective one.

"So we think even though this is probably a rare cause for this disease, it probably has greater meaning for other families, which might have genetic defects in the same pathway," Zuchner said.

Zuchner emphasized that he needs to conduct many more studies on zebrafish before patients can benefit.

His findings are published in the current issue of the American Journal of Human Genetics. [ | FPR Super Spot]