3 Marietta brothers diagnosed with same form of cancer

Retinoblastoma is an eye cancer that begins in the retina.

Retinoblastoma is most common form of cancer affecting children’s eyes

Angie Rush lost her left eye to retinoblastoma when she was 6 weeks old. Her sons have a better prognosis.

All three of Rush’s boys — Tristen, 5; Caison, 3; and Carter , 7 months — have been diagnosed with and are being treated for retinoblastoma, the most common form of cancer that affects children’s eyes.

» Cobb students raising money for childhood cancer patients, survivors

"It was surprising, but we knew that the chances were 50/50," Rush told "Good Morning America." "I had been told by doctors most of my life that because of the genetic mutation with the retinoblastoma that I have in both eyes I had a 50/50 chance of passing it on."

Angie and Aaron Rush’s youngest son was diagnosed last month.

Tristen started chemotherapy at 3 weeks old; Caison at 1 week old, 11 Alive reported.

"(I)t is very rare for all three of the children to be diagnosed,"Dr. Thomas Olson, director of the solid tumor program at the Aflac Cancer and Blood Disorders Center of Children's Healthcare of Atlanta,  told "GMA." "It's a risk when you have familial bilateral retinoblastoma."

According to the Mayo Clinic, only one parent needs a copy of the mutated gene to pass the increased risk of retinoblastoma on to the children. "If one parent carries a mutated gene, each child has a 50 percent chance of inheriting that gene."

Having a genetic mutation doesn't mean cancer is inevitable, however.

Angie Rush told 11 Alive she “never imagined all three would be diagnosed.”

"I feel a lot of guilt, knowing that this is something I could pass down to them. But I also know that I've been blessed," she said.

"They're smart, and they're kind, they're definitely a joy to have," she told 11 Alive.

Because Angie Rush had retinoblastoma, the boys were checked at birth for the mutation and their treatment began quickly. “GMA” reported the boys receive chemotherapy once a month, along with eye checks and laser treatments.

The Rushes told "GMA" they are grateful for the support they've received. The family had to sell their house and move in with relatives to pay medical costs, but their GoFundMe page has raised $63,000 from more than a thousand donors.

"The encouragement, people saying they're thinking of us, it's been wonderful," Angie Rush said. "The monetary support has been wonderful, too."

» Childhood leukemia may be triggered by germs and could be prevented, study suggests

In Other News