Effect of deletions in the α-globin gene on the phenotype severity of β-thalassemia

• Published in: Hemoglobin Vol. 46; no. 2; pp. 118 - 123
• Main Authors: Saha, Dipankar, Chowdhury, Prosanto Kr, Panja, Amrita, Pal, Debashis, Nayek, Kaustav, Chakraborty, Gispati, Sharma, Prashant, Das, Reena, Basu, Surupa, Chatterjee, Raghunath, Basu, Anupam
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 04-03-2022
• Subjects: clinical severity; genotype; hemoglobinopathy; α-Globin gene deletion; β-thalassemia (β-thal)
• DOI: 10.1080/03630269.2022.2088381
• EISSN: 1532-432X
• ISSN: 0363-0269

Thalassemia is the most common inherited hemoglobinopathy worldwide. Variation of clinical symptoms in this hemoglobinopathy entails differences in disease-onset and transfusion requirements. The aim of this study was to investigate the role of α-globin gene deletions in modulating the clinical heterogeneity of β-thalassemia (β-thal) syndromes. A total number 270 β-thal subjects were enrolled. Hematological parameters were recorded. β-Globin mutations were determined by amplified refractory mutation system-polymerase chain reaction (ARMS-PCR), gap-PCR and Sanger sequencing. α-Globin gene deletions were determined by multiplex PCR. Out of 270 β-thal subjects, 19 carried β
+
/β
+
, 74 had β
0
/β
0
and 177 had the β
0
/β
+
genotype. When we determined the severity of the different β-thal subjects in coinherited with the α gene deletion, it was revealed that, 84.2% β
+
/β
+
subjects carried a non severe phenotype and did not have an α gene deletion. Of the β
0
/β
0
individuals, 95.9% presented a severe phenotype, irrespective of α-globin gene deletions. In cases with the β
0
/β
+
genotype, 19.2% subjects also carried a deletion on the α gene. Of these, 61.8% presented a non severe phenotype and 38.2% were severely affected. Only in the β
0
/β
+
category did α gene deletions make a significant contribution (p < 0.001) toward alleviation of clinical severity. Therefore, it can be stated that α-globin gene deletions play a role in ameliorating the phenotype in patients with a β
+
/β
0
genotype.