Phenotypic effect of α-globin gene numbers on Indian sickle β-thalassemia patients

Sickle cell β-thalassemia is a compound heterozygous state of β-thalassemia and sickle cell anemia. Patient with these conditions showed mild-to-severe clinical phenotype.

The objective of this study was to evaluate the effects of α-globin gene numbers on the phenotype of sickle cell β-thalassemia patients.

Seventy-five sickle cell β-thalassemia patients were characterized. Clinical, hematological, and molecular characterization was performed in all subjects. Amplified refectory mutation system-polymerase chain reaction was applied for β-thalassemia mutation study while α-genotyping was conducted by Gap-PCR.

Highest frequency of IVS1-5 (33 out of 75 patients) β-thalassemia genotype was recorded. Twenty-eight patients were reported with α-globin chain deletion while four had α-triplications (Anti α-3.7kb). Sickle β-thalassemia patients with α-chain deletions ameliorate hematological and clinical variables.

This study indicates that the coexistence of α-globin chain deletions showed mild phenotype instead of absence of α-chain deletions while the patients with triplication of α-genes express severe phenotype.