WOODBURY - Robin Roberts, anchor for ABC's "Good Morning America," today announced that she has been diagnosed with a rare blood disorder. Roberts says the disease, Myelodysplastic Syndrome (MDS), was likely caused by her treatment for breast cancer five years ago. She will stay on the air as she begins chemotherapy ahead of a bone marrow transplant this fall. She will receive the transplant from her sister. According to Dr. Vladimir Gotlieb, chief of hematology and oncology at Nassau University Medical Center, MDS affects approximately 1 percent of all breast cancer patients. He also says Roberts is very lucky since there is a limited pool of African-American donors. Roberts says she wants to use her ailment as a means to teach others to become donors.