Laboratory features of hemoglobinopathies

Introduction. Hemoglobinopathies are a group of diseases caused by aberrations in the HBB gene encoding the beta chain of globin. The range of possible aberrations is diverse and has regional specifi city.

Aim: to determine the laboratory and molecular genetic characteristics of beta-thalassemia and qualitative hemoglobinopathies.

Methods. In total, 268 patients suspected for having some types of the hereditary anemia were included in the study. All patients underwent capillary electrophoresis of hemoglobin using the Minicap Sebia device and the group either with elevated HbA2/HbF fractions or with the presence of pathological Hb variants was selected. The direct automatic Sanger sequencing of the HBB gene was performed in the selected group.

Results. The analyzed group had 33 electrophoresis positive patients out of 268. Some pathological variants of hemoglobin including HbS, Hb Shepherds Bush and an unknown pathological Hb variant were detected. According to the results of genotyping, aberrations in the HBB gene were detected in 24 of 33 patients, of which 21 patients confi rmed the presence of beta-thalassemia, the rest of the detected aberrations were characteristic of various hemoglobinopathies. The most common mutation characteristic of beta-thalassemia was HB:c.25_26delAA, which was detected in 33.3% of cases. The pathogenic effect of an aberration with previously unknown clinical signifi cance has been determined — HBB:c.93-36CT.

Conclusion. Capillary electrophoresis of hemoglobin can be used for beta-thalassemia screening. However, the diagnosis confi rmation is carried out by molecular genetic studies. The detected aberrations spectrum for beta-thalassemia and hemoglobinopathies is extremely diverse and it includes some extremely rare hemoglobinopathy types requiring further investigations.

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