( CNN ) -- Robin Roberts ' battle against myelodysplastic syndrome , or MDS , is just beginning . The `` Good Morning America '' anchor will undergo chemotherapy before having a bone marrow transplant later this year . `` Bone marrow donors are scarce and particularly for African-American women , '' Roberts wrote Monday . `` I am very fortunate to have a sister who is an excellent match , and this greatly improves my chances for a cure . '' More than 10,000 people in the United States are diagnosed with blood-related disorders every year , according to the National Marrow Donor Program . Often the best treatment is a bone marrow transplant . During the procedure , a donor 's stem cells are directly transfused into the sick patient 's bloodstream . The patient 's new cells multiply over time to create healthy bone marrow . Unfortunately , the chance of finding a match on the national registry is as low as 66 % for African-Americans and other minorities , compared with 93 % for Caucasians . Be the Match , the national registry , has 10 million potential donors , but only 7 % are African-American . While the percentage is comparable to the overall African-American population in the United States ( which is 12 % ) , the registry is meeting only about a third of the needs for African-American transplants , said Dr. Jeffrey Chell , CEO of the National Marrow Donor Program . Tuskegee 's ghosts : Fear hinders black marrow donation . It 's a disparity that 's come up time and again . Last year , the death of Shannon Tavarez attracted attention because doctors were unable to find a bone marrow match for the young Broadway star , who had acute myeloid leukemia . `` It 's absolutely critical to have more people on the registry , '' Chell said . `` You 're more likely to find a match with someone who shares your common ancestry or ethnicity . '' African-Americans and bone marrow donations . Be the Match tests the immune system 's genetic coding to determine bone marrow compatibility . The human immune system has evolved over thousands of years , which is why racial and ethic background is so important . For instance , European-Americans ' ancestors may have survived the medieval plague , while African-Americans could have a natural immunity to malaria because of their ancestors ' environmental pressures . If a good match is n't found , the donor 's immune system will attack the sick patient 's `` foreign '' cells in a condition called graft-versus-host disease . As Roberts ' situation shows , a sibling is often the best genetic match . But 70 % of transplant patients will end up using a complete stranger 's bone marrow , according to Katharina Harf , chief inspiration officer of DKMS , the world 's largest donation center . `` My mother ( who had blood cancer ) had six siblings and none of them matched , '' Harf wrote in a statement . `` That 's why we started DKMS , to help other patients in need -- so no family would have to go through what we did . '' DKMS recently teamed up with Help Remedies to create a first aid kit that includes bandages and a bone marrow testing kit . Now when you get a paper cut , you can possibly save a life . Chell said Be the Match wants to encourage people to sign up for the registry by dispelling the myth that the donation process is complicated or painful . The registry is launching a national campaign in July for African-American Bone Marrow Awareness Month . But `` nothing works as well as someone who has the courage like Robin Roberts to step forward and let people know what she 's going through , '' Chell said , adding the registry has received an influx of potential donors to its site since Roberts ' announcement . To sign up to be a donor , you must be between 18 and 60 years old and be in good health . Visit BeTheMatch.org for information . Related story : Cord blood stem cells help meet minority marrow needs .
Chance of finding a bone marrow match is as low as 66 % for African-Americans . Registry meeting only about a third of the needs for African-American transplants , doctor says . Donor official says 70 % of transplant patients will end up using stranger 's bone marrow .