Identification of hemoglobin variants with DNA sequencing

ABSTRACTIdentification of Hemoglobin Variants with DNA SequencingThe haemoglobinopathies refer to a diverse group of inherited disorderscharacterized by a reduced synthesis of one or more globin chains (thalassaemias) orthe synthesis of a structurally abnormal haemoglobin (Hb). In prevalent regions, thethalassaemias often coexist with a variety of structural Hb variants giving rise tocomplex genotypes and an extremely wide spectrum of clinical and haematologicalphenotypes. An appreciation of these phenotypes is needed to facilitate the definitivediagnosis of the causative mutations to inform management and clinical counselling.Haematological and biochemical investigations, and family studies provide essentialclues to the different interactions and are fundamental to DNA diagnostics of the Hbdisorders. Although a full spectrum of >1000 mutations causing haemoglobinopathieshave been documented, in practice only a limited number of mutations are associatedwith disease states and clinical significance.So far up to present 42 abnormal hemoglobins have been identified in the ourcountry. There are big differences in the distribution of abnormal hemoglobinsamong regions. In Çukurova region β-thalassemia and HbS are the most commonvariants. Some of abnormal hemoglobins can?t be identified with electrophoretictechniques. So these case must be idendified with DNA sequence.Key Words: Hemoglobin variants, DNA sequencing, thalassemia,.