Several hemoglobin variants have electrophoretic behavior similar to hemoglobin S, which may lead to false diagnosis for sickle-cell disorders in newborn screening programs. A homozygous hemoglobin with S mobility was detected in two unrelated babies in Brazil.Methods:
Isoelectric focusing and high-performance liquid chromatography assays, gene sequencing, and restriction fragment length polymorphism with AfeI were used to characterize the hemoglobin.Results:
Hb Stanleyville-II and −α3.7/−α3.7 type I deletion in the α-globin gene was diagnosed. Parents were heterozygous for both Hb Stanleyville-II and α-thalassemia. Hypochromia and microcytosis were probably due to the homozygous α-thalassemia.Conclusion:
Stanleyville-II gene mutation is HBA2:c.237C>A, or C>G, and this information on the Globin Gene Server should be updated; AfeI test is a fast and accurate method to detect it; NBS programs should consider the possibility of Hb Stanleyville-II whenever IEF shows one band in the HbS position, and another one between S and C.