The Gγ‐δβ‐thalassemia and Gγ‐β°‐HPFH conditions in combination with β‐thalassemia and Hb S

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Abstract
A combination of 2 forms of thalassemia has been observed in a member of a South Carolina family. The proposita, a 34‐year‐old black female with hemolytic anemia, had over 50% fetal hemoglobin, an elevated level of hemoglobin A2, and in vitro imbalance in chain synthesis. Family studies revealed a δβ‐thalassemia heterozygosity in her mother and 2 sibs and a β‐thalassemia heterozygosity in her son. The fetal hemoglobin of the δβ heterozygotes was of the Gγ type (i.e., the γ chain had glycine in position 136). Consequently, it may be concluded that the propositus has Gγ‐δβ‐thalassemia‐β+ thalassemia; this is the first time that such a combination has been recognized. In 3 members of another family this same type of Gγ‐δβ‐thalassemia occurred in combination with Hb S, whereas Gγ‐β°‐HPFH (hereditary persistence of fetal hemoglobin) and Hb S were present in 1 member of a third family. Clinical features and laboratory findings were specific for each condition and permitted a clear distinction between Gγ‐δβ‐thalassemia and Gγ‐β°‐HPFH. The discussion correlates these findings with data from 80 persons in 30 families whose Hb F was elevated and contained only Gγ chains.