Novel sequence insertion in a Mâori patient with transfusion-dependent beta-thalassaemia.

Although beta-thalassaemia is common throughout the world, it has not been previously described in Polynesia. We report a novel sequence insertion where homozygosity for the defect results in transfusion-dependent anaemia. The repeated 45 base pair (bp) insertion causes duplication of the start codon and consequent transcription from the original initiation code would be predicted to lead to the production of an irrelevant seven-residue peptide, while residual translation from the novel initiation site would result in diminished yields of beta-globin and consequent clinical beta(+)-thalassaemia.