A rare mutation [IVS-I-130 (G-A)] in a Turkish β-thalassemia major patient

Abstract

Here we describe the identification of the rare β-thalassemia mutation IVS-I-130 (G-A) for the first time in Turkey. The hematological evaluation of the patient showed classical signs of β-thalassemia major requiring regular blood transfusions every 30–35 days. DNA analysis was carried out using reverse dot-blot hybridization and restriction endonuclease digestion, as well as genomic sequencing. The patient was found to be heterozygous for the IVS-I-6 (T-C) and IVS-I-130 (G-A) mutations. In order to deduce a possible origin for the IVS-I-130 (G-A) mutation, the sequence polymorphisms in the DNA of the patient and her family were characterized. The method included the analysis of nine polymorphic nucleotides and the hypervariable microsatellite of composite sequence (AT)xTy 5′ to the β-globin gene by DNA sequencing. The sequence haplotype (HT4) carrying the IVS-I-130 (G-A) mutation is also observed in Algeria. This favors a Northeastern African origin for this allele. The observed results agree well with a recent introduction of this mutation to Turkey from Egypt toward the end of the 19th century. Am. J. Hematol. 63:223–225, 2000. © 2000 Wiley-Liss, Inc.