Luke Do was a lively 18-month-old awaiting the birth of his first sibling when he was diagnosed with a rare form of leukemia. The hopes of his parents, both doctors in San Jose, Calif., immediately turned to a bone marrow transplant, but they soon learned some distressing news—Luke’s ethnic heritage made him a tough match.
Sarah Gaskins, Luke’s mother, has Japanese and European ancestors and his father, Lam Do, is Vietnamese-American. Because bone marrow matches usually are made with a relative or someone with the same racial or ethnic background as the patient, multiracial people rarely have success.
“It’s tragic,” said Lam Do, who specializes in internal medicine. “Your chance of finding a donor is so low, it’s like winning the lottery. And most people are unaware of this.”
Today, whites in need of a bone marrow transplant have about a 90 percent chance of finding a match, said Dr. Patrick Beatty, an oncologist with the Montana Cancer Specialists in Missoula, Mont., who researches ancestry and bone marrow. For those who aren’t white, “your chances of getting a match are pretty remote,” he said.
The biological reason has to do with the body’s response to infections, Beatty said. Because the world’s ancient peoples were exposed to different diseases over millennia, each group developed different tissue antigens, substances that help fight illness.
The descendants of these peoples retain those highly varied tissue antigens, he said, making it tough to match the bone marrow of individuals from different ancestries.