Only about 600 people in the U.S. have cystinosis. The Root brothers account for three of them. When the eldest, Marcus, was born, his family noticed regular vomiting and delayed growth. At 18 months, he was diagnosed with cystinosis, a disease that causes damage to many of the body’s important organs. His two brothers, Christopher and Austin, would also be diagnosed with the rare genetic disease before the age of 2. In all three cases, the condition caused cystine deposits throughout the body — including the kidneys — speeding up organ decline. When Marcus was 10, his kidneys reached a critical point. He received his transplant in 2016, followed by Austin (then age 9) in July 2018 and Christopher (then age 10) in September 2018. But while their medical journeys look the same, the boys behind them certainly aren’t. “They're individuals,” says their stepmother, Nicole. “Their personalities are all very different, and their strengths and their needs are different. We really celeb...