Analiza mutacji talasemii alfa u chorych diagnozowanych w Instytucie Hematologii i Transfuzjologii

Abstract Background Alpha-thalassemia is genetically transmitted hemolytic anemia resulting from disturbance of the globins chain synthesis. Alpha-thalassemia is caused most frequently by deletions and less commonly by nondeletional defects. Aim To introduce the molecular methods for routine identifications of alpha-thalassemia mutations and to study the characteristics of these mutations in Poland. Methods Blood sample of 155 patients with normal or reduced HbA 2 values was obtained for blood counting. All samples underwent gap-PCR to screen for the seven common α-thal deletions and MLPA analysis. The DNA of 21 patients in which deletions were not detected has been directly sequenced. Results We detected mutations in the alpha-globin gene in 72 of 155 patients studied. 55 out of 72 cases showed most common thalassemia deletions, as the following: a single gene deletion (α 3.7 and α 4.2 ) and both genes deletion (FIL, SEA, MED I, and α 20.5 ). Owing to the use of MLPA technique, we found nontypical deletions in another 12 patients and multiplication of the alpha-globin genes in further 4 cases. We also identified a patient with a point mutation HBA2 : c.300 + 2Tu003eA by DNA sequencing. Conclusions Molecular analysis of the alpha-globin cluster is required for a correct diagnosis in patients with normal or reduced level of HbA 2 . The results of the study show that due to the progressive migration of the population and globalization, thalassemia must be included in the differential diagnosis of anemia in Poland.