Pak has severe aplastic anemia. He also has a rare bone disorder called osteogenesis imperfecta Type 4. He is of Korean ancestry.

Roy Yonashiro, Hawai'i Bone Marrow Donor Registry recruitment coordinator, said Pak's condition limits how active he can be. But he does like to tell jokes, watch TV and play video games.

Yonashiro said some characteristics of marrow type are unique to people of specific ancestry. However, it's possible for patients to match donors from other racial and ethnic groups.

He said marrow transplants require certain matching tissue traits between donor and patients. Because those traits are inherited in the same way people inherit hair or eye color, a match is more likely to come from within a patient's own family.

But Yonashiro said 70 percent of those who need transplants cannot find a match within their own family. And that's why they need to find healthy individuals willing to donate.

To sign up as a bone marrow donor, you must be between 18 and 60 years old and in good health; be willing to provide a blood sample that will be sent for tissue typing to test for potential matches; be willing to donate not knowing whom you will match; and provide two contacts to help the registry find you if a match is found.

For more information, call the registry at 547-6154 or check www.marrow.org.