[beta-thalassemia minor diagnosed in a patient with chronic myelogenous leukemia during hydroxyurea therapy]. 
A 55-year-old man was admitted to our hospital because of leukocytosis and microcytic anemia with hypochromia, target cells, and increased levels of hemoglobin A2 and hemoglobin F. The results of a gene analysis yielded a diagnosis of chronic myelogenous leukemia and beta-thalassemia minor.  A gradual increase in hemoglobin was observed during hydroxyurea therapy, which was performed over a 12-week period.  This increment appeared to be due to suppressed production of myeloid cells.  It was been reported that hydroxyurea increases total hemoglobin due to increased hemoglobin F synthesis in patients with beta-thalassemia.  However, hydroxyurea had no clear influence on hemoglobin concentration in this case.