IDENTIFICATION OF TWO NEW α-THALASSEMIA MUTATIONS IN EXON 2 OF THE α1-GLOBIN GENE

Abstract

The most common causes of α-thalassemia are deletions that remove one or both of the functional α-globin genes. In addition, more than 30 different point mutations and small deletions/insertions have been reported for the α-globin genes. Here, we describe two new mutations occurring in exon 2 of the α1-globin gene. One mutation is an insertion of 21 bp that gives rise to a predicted α-globin chain containing a duplication of amino acid residues 93–99. The second mutation is a 33 bp deletion resulting in a predicted α-globin chain that is missing amino acid residues 64–74. Neither mutation results in a detectable hemoglobin variant, indicating that the variant α-globin chains are highly unstable. Carriers of these mutations have mild microcytosis and the phenotype of α⁺-thalassemia trait.