1. The clinical, hematologic and biochemical findings in a patient with hereditary hypochromic hypersideremic anemia are described. The pattern of heme and globin production, measured by glycine-2-C14 incorporation, suggests an abnormality of globin synthesis.
2. The hypothesis that this disorder might represent a variant of thalassemia, probably α-thalassemia, is discussed.
3. The partial therapeutic response to pyridoxine is considered to be due to pharmacodynamic stimulation of heme synthesis. The hemoglobin level was not restored to normal, probably because of the limited capacity for globin synthesis.
4. It is suggested that kinetic studies of hemoglobin synthesis may aid in the classification of hereditary hypochromic hypersideremic anemias.