NEW : ` It 's very simple to be part of the registry , '' she said . ABC host 's sister says she 's a `` perfect match '' for a marrow transplant . ` ` Good Morning America '' co-anchor Robin Roberts faces MDS diagnosis . The disease attacks blood and bone marrow . It is the most common form of leukemia, but it can also be caused by other cancers or infections. she writes .
NEW : ABC host 's sister says she 's a `` perfect match '' for a marrow transplant . ` ` Good Morning America '' co-anchor Robin Roberts faces MDS diagnosis . The disease attacks blood and bone marrow . It is the most common form of leukemia, but it can also be caused by other cancers or infections. she writes .