Three young brothers are fighting the same rare childhood cancer

Three brothers -- Tristen, 5, Caison, 3, and Carter, 7 months -- are battling the same type of rare childhood cancer.
Three brothers -- Tristen, 5, Caison, 3, and Carter, 7 months -- are battling the same type of rare childhood cancer. (Rush family)

Three brothers, none of them older than 5, are battling the same type of rare childhood cancer.

Aaron and Angie Rush have three boys -- Tristen, 5, Caison, 3, and Carter, 7 months -- and all have been diagnosed with retinoblastoma.

“It was a shock and it was a surprise. It was very emotional. It’s hard to handle sometimes,” Angie told CNN’s sister network HLN. “But they are such a blessing.”

Retinoblastoma is an eye cancer that begins in the retina and commonly affects young children, according to the website for the Mayo Clinic. It can occur in one or both eyes and is the most common form of eye cancer in children.

As a child, Angie battled the same cancer. She said she knew there was a 50% chance of passing it onto her own children but never expected all three would have to fight the same disease.

"But I've done great. I'm a teacher and I'm hoping to make a difference," Angie said.

According to Mayo, gene mutations increase the risk of retinoblastoma being passed on from parents to children. Hereditary retinoblastoma tends to develop at an earlier age.