Nick Glasgow, a 28-year-old bodybuilder who is one-quarter Japanese, has had his doctor warn him the outlook was grim.
Glasgow's background would make it almost impossible to find a match, which usually comes from a patient's own ethnic group.
The doctor "didn't say it was slim-to-none. He didn't say it would be hard. He said 'zero chance."
"The truth is, when people of different backgrounds marry and produce offspring, it creates more types that are harder to match," said Michelle Setterholm, the program's director of scientific services. "The probability just gets lower when you have people of mixed ancestral DNA."
The reason that mixed-heritage patients are so hard to match can be found in the immune system.
Populations in different parts of the world developed certain proteins, or markers, that are part of the body's natural defenses. These markers help the immune system determine which cells are foreign and should be rejected.
A match between two people who share many markers will reduce the risk of the donor and recipient cells attacking each other. Because certain markers tend to cluster in particular ethnic groups, matches are most often found among people of shared backgrounds. Multiracial patients often have uncommon profiles and a much harder time finding a donor.
Finding compatible organs for transplant is simpler. Organ matches rely essentially on blood type, which is not related to race.
From his Japanese grandmother, Glasgow got the almond shape of his eyes and cell markers that set him apart from most other whites. From his white grandparents, he got markers that set him apart from other Japanese. http://www.nbcnews.com/.../marrow-donors-elusive.../