Characterization of Clinical and Laboratory Profiles of the Deletional α2-Globin Gene Polyadenylation Signal Sequence (AATAAA > AATA– –) in an Indian Population

Abstract

α-Thalassemia (α-thal) is characterized by large deletions involving the variable regions of α2 and/or α1 genes. Nondeletional mutations and polyadenylation (polyA) signal sequence motif mutations are less common. In this retrospective study, we describe a fragment length analysis-based polymerase chain reaction (PCR) assay for screening the T^Indian (AATAAA > AATA– –; HBA2: c.*93_*94delAA) polyA signal deletion along with its clinical and laboratory presentation in 21 patients. Most of the patients were diagnosed in early adulthood with a clinical presentation ranging from asymptomatic in the heterozygous state to severe Hb H disease with a prominent hemolytic component in the homozygous state. On genetic analysis, 14 patients were found to be homozygotes, five were compound heterozygotes and two were heterozygotes. Thus, the T^Indian polyA signal deletion is common in the Indian population and should be screened for in patients with nondeletional α-thal mutations.

• Nondeletional α-thalassemia (α-thal)
• Polyadenylation (polyA) signal mutation
• T^Indian polyA signal deletion

Acknowledgements

The authors would like to thank Dr. Jude J. Fleming (Professor, Department of Biochemistry, Christian Medical College, Vellore, Tamil Nadu, India) for his critical review and editing of the presented manuscript.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.