Molecular basis of a high Hb A/Hb F-thalassemia trait: a retrospective analysis, genotype-phenotype interaction, diagnostic implication, and identification of a novel interaction with -globin gene triplication.

Background: -thalassemia deletion removing 5´-globin promoter usually presents phenotype with high hemoglobin (Hb) A and Hb F levels. We report the molecular characteristics and phenotype-genotype correlation in a large cohort of the -thalassemia with 3.4 kb deletion.