A very rare disorder in which the bone marrow doesn’t make enough red blood cells. It is usually seen in the first year of life. Patients may have deformed thumbs and other physical problems. They also have an increased risk of leukemia and sarcoma, especially osteosarcoma (bone cancer). Patients with Blackfan–Diamond anemia may have a mutation (change) in one of the genes that make proteins found in the cell’s ribosomes.