Hemoglobin SC, SS/G_Philadelphia and SO_Arab diseases. Diagnostic importance of an integrative analysis of clinical, hematologic and electrophoretic findings

Hemoglobin studies are presented on two children in whom electrophoretic analysis of hemolysates at alkaline pH initially suggested the diagnosis of hemoglobin SC disease. In both patients the course of the disease was unusually severe, blood smears contained irreversibly sickled cells, and crystal formation did not occur when red cells were incubated in 3 per cent sodium chloride solution. Each of these findings is inconsistent with the interpretation of the electrophoretic patterns. Family studies demonstrated that one of the patients had sickle cell anemia and was also a carrier of an alpha chain variant; citrate agar electrophoresis at pH 6.2 of the second child's hemolysate revealed that the "C-like" hemoglobin was not hemoglobin C. Tryptic peptide analyses of the nonhemoglobin S fractions showed that the first child has SS/G_Philadelphia disease and that the second child has SO_Arab disease. These observations emphasize the importance of integrating the clinical and hematologic data with the results of electrophoretic procedures in order to define precisely the hemoglobin abnormality in patients with sickling disorders.