Three New β-Thalassemia Mutations with Varying Degrees of Severity

Abstract

We report the identification of three, new β-thalassemia (β-thal) mutations with varying degrees of severity. The most severe mutation, a frameshift mutation in exon 3 of the β-globin gene [codon 120 (−A)], was associated with a dominant β-thal phenotype. A second frameshift mutation, codon 50 (−T), resulted in a phenotype of typical high Hb A₂ β-thal trait. The mildest mutation was IVS-II-2 (T > C), which changes the splice donor sequence of IVS-II from GT to GC. This transition mutation resulted in a slight reduction in β-globin gene expression and could be considered a mild β⁺-thal allele.

Keywords:

• β-Thalassemia (β-thal)
• Frameshift
• Splice junction