This study was planned to determine the frequency of β-thalassemia mutations in Batna region (Northeast Algeria). Nineteen blood samples of clinically thalassemic children patients were collected from Department of Pediatrics, University Hospital of Batna. We carried out the molecular genetics of beta globin gene by the method of minisequencing using Snapshot™ kit (Applied Biosystems) in search of the four most common HBB genetic variants including three β-thalassemia mutations: codon 39(C>T) (HBB: c.118C>T), IVSI-110(G>A) (HBB: c.93-21G>A), and IVSI-1-2(T>G) (HBB: c.92+2T>G), as well as the hemoglobin S variant (HBB: c.20A>T). We used direct DNA sequencing to detect the rare mutations of beta-globin gene. We have revealed the presence of four different β-globin gene mutations responsible for β-thalassemia in Batna region. According to our results, the nonsense mutation at codon 39 (C>T) is the most frequent mutation type in our province, the same as other geographical regions of Algeria. It is followed by codon 54(-T), detected in a second Algerian family (the proband was homozygote), and the first association of Hb Knossos: codon 27 (G>T) allele with codon 39 (C>T) in the Algerian population. Here we reportws also the association of codon 39(C>T) with IVS-I-110 (G>A). Our preliminary results show the predominance of codon 39 (c>t) mutation of HBB gene in Batna region
Clinical heterogeneity is often due to genetic heterogeneity. One mechanism by which different mutations can produce a phenotypic variation). Beta-thalassemia is mainly caused by a large number of mutations of the gene for beta-globin. The objective of this study is to correlate molecular lesions and clinical signs in children with beta-thalassemia homozygous. We carried out the molecular genetics of beta globin gene by the method of mini sequencing using Snapshot ™ kit (Applied Biosystems) in search of the mutation codon 39 (C>T) (HBB: c.118C>T) and we studied haematological parameters by statistical method using the test “t” of Student for comparing the means of the samples. The peripheral blood smear examination was done from the slides stained in Wright stains. The results obtained have shown that beta-thalassemia homozygous children with severe anemia over 30 ± 0.9 g/L of total Hb with microcytosis of 60,80 ± 2.014 fl, hypochromia 18.47 ± 0.6023 pg and the number of red blood cells is 3.220 ± 0.2778 (10¹²/L). In addition, a significantly secondary thrombocytosis and leukocytosis were reported in patients. Thus the electrophoresis of hemoglobin exhibits a high Hb F (55 to 82%). The peripheral smear examination revealed many red cell abnormalities in the blood. In this study, we used the mini sequencing assay as a rapid screening procedure to identify the severe codon 39 (C>T) mutation in the HBB gene. Phenotype of beta thalassemia major is characterized with various hematological parameters.
