Hb S (HBB: c.20A>T) and α- and β-Thalassemia Coinheritance in Iranian Patients

Hb S (HBB: c.20A>T) and α- and/or β-thalassemia (α- and/or β-thal) coinheritance is a common genetic disorder in regions with a high prevalence of thalassemia and sickle cell disease. The clinical manifestations of this coinheritance vary from mild to severe complications. Iran is a country with a high incidence of thalassemia and sickle cell disease. This study aimed to evaluate the coinheritance of sickle cell disease with α- and/or β-thal in Iranian patients. In this cross-sectional study from 2018-2019, a total of 47 participants with the Hb S abnormality, who were referred to the Zafar Thalassemia Clinic (Tehran, Iran), were selected as a study group. Molecular analysis for the evaluation of α and β gene mutations was performed in all participants. Hb SS, Hb S/β-thal and Hb S/Hb D-Punjab (also known as Hb D-Los Angeles, Hb D-Chicago, Hb D-North Carolina, Hb D-Portugal and Hb Oak Ridge) (HBB: c.364G>C) were detected in 21 (44.7%), 23 (48.9%) and three (6.4%) patients, respectively. α Gene mutations were also detected in five patients with Hb S/β-thal, four patients with sickle cell disease and one patient with Hb S/Hb D-Punjab. In the current study, -α^3.7/αα with β gene abnormalities was the most common genotype. Our study showed that the coinheritance of sickle cell disease with α- and β-thal is common and evaluation of these disorders, especially in pre marriage screening is important for diagnosis and management strategies.