Thalassemia – Increasingly Frequent Cause of Microcytic Anemias in Children in Poland

Abstract 5184

Thalassemias are a group of genetically determined hemolytic anemias related to disturbed synthesis of globin chains, and are classified as quantitative hemoglobinopathies.

We would like to present our experience in diagnosis of thalassemia in children as an increasingly frequent cause of microcytic anemias as well as to point out that it is the cause of microcytic anemia in Poland.

Between 2005–2012 we established the diagnosis of thalassemia minor in 94 children of Polish origin, referred to the Department of Pediatrics, Hematology and Oncology, Medical University of Warsaw. At admission all patients presented microcytosis, erythrocytosis, hypochromia and normal or elevated iron status. Most of them had long-lasting uneffective iron therapy in anamnesis. Their age ranged from 3 to 17 years. The group consisted of 40 girls and 54 boys.

Routinely employed diagnostic methods, including blood morphology, determination of iron and ferritin, electrophoretic separation of hemoglobins, determination of HgbA2 and HgbF, as applied in all cases, often turn out to be insufficient to diagnose thalassemia, substantiating the need to use modern molecular biological techniques.

Thalassemia alfa was diagnosed in 9 children in whom we detected deletion α 3, 7 using molecular biological techniques.

In 2 children coexistence of both thalassemia alfa and beta was established. Both children presented macrocytosis and normal range of haemoglobin and red blood cells count. The molecular biological techniques used in both cases identified deletion α 3, 7 characteristic for alfa thalassemia, and Hb Koln (Codon GTC>ATG) and Del 4, 2 (Taq1) characteristic for beta thalassemia.

In the remaining 83 patients we made the diagnosis of thalassemia beta. The diagnosis was possible after the evaluation of Hgb A2 and F levels. In 24 cases we managed to performed molecular biological techniques, identifying mutation IVS I-6 (T>C) as the most frequent.

Generally associated with the Mediterranean Basin, thalassemia is, however, more and more often diagnosed in Poland. This is due to the international human traffic. Growing availability of diagnostic tests, like molecular biological techniques, especially useful in equivocal cases, is also important.

The amplification of diagnostic possibilities by genetic tests in the future may be useful in detection of genetic mutations responsible for thalassemia and characteristic for Polish population.