[Acquired hemoglobin abnormalities (author's transl)].

Along with the hereditary forms of pathological hemoglobin, there are a certain number of acquired hemoglobin abnormalities, in particular hemoglobin H and reappearance of foetal hemoglobin. Reactivation of foetal hemoglobin synthesis is seen in a wide variety of physiopathological states and may be accompanied by other changes in erythrocytic properties. On the other hand, hemoglobin H is far more more rare and is always associated with leukemia. Study of family history and the hematologic content generally allow differentiation between an acquired abnormality and hereditary forms of pathological hemoglobin.