Aberrant mRNA Spliced in a β0-Thalassemic Gene Having a G →A Mutation at βIVS II-１
mRNA extracted from β0-thalassemia patient with a βIVS II-1G → A mutation, who had been diagnosed by hemoglobin biosynthesis and molecular analysis, was amplified by use of specific oligonucleotide primer set. Sequencing of the PCR product demonstrated that mRNA from DNA possessing G → A mutation at βIVS II-1 seemed to be an aberrant mRNA spliced at the site of dinucleotide GT at βIVS II-48-49 instead of GT at βIVS II-1-2. The mRNA produced from the mutant β-globin gene was inserted 47bp between the exons 2 and 3, which was expected to be unstable in the nucleus, and the globin chain translated from such mRNA might be shorter than the normal chain because the nonsense sequence (TGA) at the 7th codon in the inserted 47 bp was created. Thus, the production of an aberrant mRNA due to this nucleotide change (G → A) at βIVS II-1 was thought to be the cause of β0-thalassemia.