BIO-MEDICAL AND GENETIC ANALYSIS OF BETA THALASSEMIA IN THE ETHNIC GROUPS OF EASTERN NEPAL

Abstract

Hemoglobinopathies and thalassemias are the most common monogenetic disorders in Southeast Asia. These are the only genetic disease where carriers can be detected using hematological findings rather than genetic analysis. The detection of Beta-thalassemia relies on estimation of red blood cell parameters that reveal microcytic hypochromic anemia. Carriers of this disorder are usually asymptomatic and non-transfusion dependent. However, marriage between two carriers produces severe transfusion dependent Thalassemia major off-springs who seldom survive beyond two years of age. The affected families suffer psychological, emotional, social and economical stress. In Nepal, this disorder is common in the malaria endemic regions of the Terai. Therefore, this study was aimed to assess the status of hemoglobinopathies and thalassemias in some ethnic groups of the Terai region in Eastern Nepal. This descriptive cross-sectional study was done from 06/01/74 to 29/12/77. Total 1500 individuals were enrolled for screening. The blood samples and demography were collected randomly from asymptomatic individuals belonging to the Koch Rajbanshi, KochilaTharu, Musahar, Musalman and Santhal ethnic groups of Jhapa, Morang and Sunsari districts. Haematological parameters were derived from automated coulter counter, peripheral blood smear was examined microscopically, hemoglobin electrophoresis was done by Capillary electrophoresis (Sebiaminicap flex piercing) and genotyped with multiplex amplification refractory mutation system-polymerase chain reaction for nine mutations. Out of the total 1500, 285 (19%) cases suffered from microcytic hypochromia anemia. Abnormal haemoglobinopathies was detected in 184 (12%) cases. In which β thalassemia trait was (44.44%), followed by HbE trait (34.56%) and HbE Homozygous (20.98%) in overall population. In the Koch Rajbanshi ethnic group Hemoglobin E variant was the only abnormal hemoglobinopathy found. Whereas inthe Santhals only Beta-thalassemia heterozygous was detected. The mutationsidentified were C-15 (G→A), IVSI-5 (G→C), FS 8/9(-TCCT) and C-26 glu-ly. The results of this study revealed that the ethnic groups of eastern Nepal are a rich reservoir for thalassemia and hemoglobinopathies. A regional and ethnic specificity in the mutational profile among the studied population was evident.