PAT-3. Hemoglobin H disease mimics a normal pattern on hemoglobin electrophoresis.

We describe a patient with a history of chronic microcytic anemia with peripheral schistocytosis, polychromasia, and Pappenheimer bodies, treated empirically with chronic iron supplementation. Maternal prenatal screening included hemoglobin electrophoresis at alkaline pH, which resulted in an apparently normal pattern. Acid gel electrophoresis demonstrated a predominant hemoglobin A band with a second faint band running between the S and C positions. Alkaline and acid gel electrophoresis was carried out at pH 8.6 and 6.2 using Beckman Paragon agarose gels according to the manufacturer's instructions. High-performance liquid chromatography (HPLC) and isoelectric focusing were carried out at Mayo Medical Laboratories. Cation-exchange HPLC separation and isoelectric focusing confirmed the presence of hemoglobin H. Hemoglobin H is a tetramer of beta globin chains, produced in states of very reduced or absent production of alpha globin chains. Hydrops fetalis is not compatible with life, and is found when there is deletion of all four alpha globin genes, yielding a predominant pattern of hemoglobin Bart's, H, and Portland. Deletion of three alpha globin genes results in Hemoglobin H disease, with 4-30% rapidly migrating hemoglobin H and a small amount of hemoglobin Bart's. In our case, the apparently normal pattern was produced by fast migration of the hemoglobin H band off the alkaline gel but presence of the band between S and C on the acid gel. Repeat alkaline gel electrophoresis with a shorter run time was unable to adequately resolve the hemoglobin H band. This may be a limitation of the electrophoresis method in this system, and may be an argument for standard use of HPLC methodology instead of electrophoresis for initial hemoglobin screening.

Ahsanuddin AN, Frederick CL, Posey YF. Department of Pathology and Laboratory Medicine, Brody School of Medicine of East Carolina University, Greenville, NC.