Triple heterozygosity of a hemoglobin variant: hemoglobin Pyrgos with other hemoglobinopathies.

This article is the first report of hemoglobin (Hb) Pyrgos along with other Hbs forming triple-heterozvgous patterns. Of 2 cases, the first occurred in a Thai girl with thalassemic facies, marked anemia, and hepatosplenomegaly, who had Hb Pyrgos in association with Hb H disease with Hb Constant Spring (CS). This case represents a triple heterozygosity comprising Hb Pyrgos, alpha-thalassemia 1, and Hb CS. Hb electrophoresis revealed an abnormal Hb in addition to Hbs CS, A2, A, Bart's, and H. This abnormal Hb moved slightly faster than Hb A but more slowly than Hb Bart's. Polymerase chain reaction revealed that the abnormal Hb was caused by a missense mutation within codon 83 of the beta-globin gene (GGC to GAC) resulting in a glycine-to-aspartic acid substitution, which corresponds to Hb Pyrgos. The patient required blood transfusions by the age of 3 years. A splenectomy was performed when she was 5 years old, after which her hematocrit level remained above 32%. The second case was the patient's older sister who was also triple heterozygous (Hb Pyrgos, E, and CS) but was healthy.