The nondeletional types of Hb H disease in Guangxi.

Three primers were designed, one specific for alpha 1-globin DNA, a second for alpha 2-globin DNA, and a third that is common for both alpha 1- and alpha 2-globin DNA. These three primers can be applied for selective amplification of the two globin DNA fragments, which is useful for identification of nondeletional types of Hb H disease. Fifty-nine DNA samples of Hb H patients from Guangxi were studied by selective amplification, and 27 cases (45.8%) were confirmed as nondeletional types. Of these, 22 (81.5%) had the Hb Constant Spring (CS) mutation and one had the Hb Quong Sze (QS) mutation; both were identified by hybridization with synthesized oligonucleotide probes. Nondeletional Hb H disease in Guangxi seems to be more severe than the deletional types. The average hemoglobin level of the nondeletional Hb H/CS (--/alpha alpha) is 6.8 g/dl, which is lower than that of the deletional types (7.9 g/dl), while the levels of Hb H and Hb Bart's were much higher in the patients with Hb H/CS than in those with the deletional types.