Hemoglobin SO Arab and hemoglobin CO Arab diseases. Clinical and laboratory study

A nine-year-old black female who had been considered to have Hb SC disease was admitted with pain of the leg, neck, and upper chest. She had also been hospitalized approximately 20 times for treatment of recurrent pain. Further investigation by citrate agar gel electrophoresis and peptide mapping disclosed that the child had Hb SO Arab disease. She had mild hepatosplenomegaly and the hemoglobin concentration was 10.2 gm/dl. The clinical presentation of Hb SO Arab disease of our patient resembled that of Hb SD disease and was more severe than is Hb SC disease. The mother was found to have Hb O Arab trait. Two of the patient's siblings from a different father were found to have Hb CO Arab disease, an extremely rare condition. These children, 8 and 12 years old, are clinically asymptomatic. Clinical and laboratory data are presented.