β+-Thalassemia trait due to a novel mutation in the β-globin gene promoter: -26 (A>C) [HBB c.-76A>C].

We report the case of a woman with β(+)-thalassemia (β(+)-thal) trait, in which there were two sequence variants within the β-globin gene promoter: -54 (G>A) [HBB c.-104G>A] and -26 (A>C) [HBB c.-76A>C]. Data from other patients indicate that the -54 substitution is a non pathogenic sequence variant. Therefore, the β-thal phenotype is most likely due to the -26 mutation that is adjacent to the conserved ATAA box.