Coinheritance of the different copy numbers of α-globin gene modifies severity of β-thalassemia/Hb E disease

Abstract

β-Thalassemia/Hb E patients show a range of clinical severities, from nearly asymptomatic to transfusion-dependent thalassemia major. This study investigated the clinical heterogeneity and hematologic parameters obtained in the large cohort of 925 Thai β0-thalassemia/Hb E patients. Coinheritance of α-thalassemia with β0-thalassemia/Hb E produces a milder clinical phenotype in contrast to an interaction of α-globin gene triplication in severe thalassemia. The mean steady-state Hb was also higher, whereas the mean corpuscular volume and the percentage of Hb F were markedly lower in the former group. This finding demonstrates that the genetic combination leading to the more/less degree of α- to non-α-globin chains imbalance is indeed the cause of the severe/ mild thalassemia phenotype. © Springer-Verlag 2007.