Care for Haemoglobinopathy Patients in Slovakia.

BACKGROUND: The paper presents the results od 22-year study of screening and follow-up of haemoglobinopathies in Slovakia, an overview of genetic mutations, the coincidence with hereditary haemochromatosis mutations, and the procedure in genetic councelling. METHODS: Between 1993-2015, in three centres in Bratislava and in one centre in Kosice, carriers of beta-thalassaemic genes or other haemoglobinopathies were searched for. Diagnosis was performed by haematologists, whereby the family history was evaluated, together with the overall clinical condition, blood count and blood smear, iron and haemolysis parameters, mutations of hereditary haemochromatosis, and haemoglobin electrophoresis testing. In the last years the haemoglobin division also examined by high performance liquid chromatography (HPLC). RESULTS: A clinical suspicion of the heterozygous form of beta-thalassaemia or other haemoglobinopathies was documented in 554 patients. Of them 32 (5.8%) were foreigners. 213 (38.45%) patients were genetically examined. In 190 (33.93%) of them heterozygote beta-thalassaemia was confirmed. The most frequent mutations were IVS 1.110 (33.15%), IVS 2.1 (33.15%), and IVS 1.6 (14.7%). Evidence of haemoglobin S (heterozygote sickle cell anaemia) was also notable in two non-relative children, whose fathers were of African origin, and one patient from Ghana. One female patient was followed up for haemoglobin Santa Ana (non-stabile haemoglobin previously diagnosed as mutation de novo). In our group, we took care of pregnant patients with haemoglobinopathies. CONCLUSIONS: The study showed that there is a higher number of heterozygotes for beta-thalassaemia and rarely haemoglobinopathies in Slovakia. Over the past years, we have recorded an increase number of foreigners coming to our country. It is necessary to continue in search of pathological gene carriers to avoid serious forms of haemoglobinopathies.

Molecular Characterization of ß-Thalassemia in the Czech and Slovak Populations: Mediterranean, Asian and Unique Mutations.

ß-Thalassemia (ß-thal) is considered rare in Central Europe. As in other malaria-free regions, the presence of ß-thal in Central Europe reflects historical and recent immigration, and demographic changes that have influenced the genetic variability of the current populations living in this area. This study assesses the frequency and spectrum of mutations on the ß-globin gene in Czech and Slovak subjects with clinical symptoms of thalassemia. The results of the initial part of this research were published more than two decades ago; the aim of this study was to update these original reports. During the period from 2002 to 2015, 400 cases from Czech and Slovak hematological centers were analyzed. Twenty-nine ß-thal mutations, identified in 356 heterozygotes from 218 unrelated families, involve five unique mutations including a recently described insertion of a transposable L1 element into the ß-globin gene. One mutation described here is reported for the first time. Most of the mutations were of Mediterranean origin and accounted for 82.0% of cases. All but one case studied were heterozygous carriers, manifesting ß-thal minor, with rare exceptions represented by the rare (ß(0)) codons 46/47 (+G) (HBB: c.142_142dupG) mutation associated with an α-globin gene quadruplication and by dominantly inherited ß-thal with a more severe phenotype. One double heterozygous ß-thal patient was a recent immigrant from Moldavia. The list of δß-thal alleles (26 carriers, 16 families) contains Hb Lepore and two types of δß(0)-thal deletions. In the past, genetic drift and migration as well as recent immigrations were responsible for the introduction of Mediterranean alleles, while several mutations described in single families were of local origin.

Nineteen years study of beta-thalassaemia in Slovakia.

BACKGROUND: Beta-thalassaemia is a congenital disorder caused by point mutations in a haemoglobin beta-globin chain. The heterozygous form produces microcytosis and normal iron levels, however, haemoglobin electrophoresis shows elevated amounts of haemoglobin A2 and eventually foetal haemoglobin F as well. METHODS: Between 2005-2011, in three centres in Slovakia, carriers of beta-thalassaemic genes or other haemoglobinopathies were searched for. Diagnosis was performed by haematologists whereby the family history was evaluated, together with the overall clinical condition, blood count and blood smear, iron parameters, haemolysis and haemoglobin electrophoresis testing. A proportion of patients was examined by molecular genetic methods. RESULTS: A clinical suspicion of the heterozygous form of beta-thalassaemia was documented in 402 patients (21.9%) out of a total of 1,834 examinations. From these patients, 87 underwent molecular genetic testing and mutations of beta globin genes were identified in 70 of them, where the most frequent mutations were IVS 2.1 (28.5%), IVS 1.110 (25.6%) and IVS 1.1 (11.3%). Evidence of haemoglobin S (sickle cell anaemia) was also notable in one case (patient of African origin). Unusually high levels of haemoglobin F (6-21%) were found in 23 adult subjects. CONCLUSION: The study showed that there is a higher number of heterozygotes for beta-thalassaemia and rarely haemoglobinopathies. It is necessary to continue in search of pathological gene carriers in Slovakia.