Prevalence Sickle Cell Disease In Tharu Communities Of Rupandehi District, Nepal

Abstract

The general objective of this work is to find the prevalence of Sickle Cell Disease in Tharu communities of Rupandehi district, Nepal and specific objectives are to compare prevalence of sickle cell disease among different sub-ethnic groups of Tharu community of Rupandehi district, Nepal; to find out genotype and allele frequency of SCD and sickle cell allele respectively in Tharu community of Rupandehi district, Nepal and to compare the preference between sickling test and sickle cell solubility test method for screening of SCD. The blood samples were collected randomly from members of Tharu community of Rupandehi district aged above 3 years.. Sickling test and sickle cell solubility test were conducted on all samples for screening of presence of sickle hemoglobin(HbS) (HBB: c.20A>T) in the blood. The samples detected to be positive from either of these two methods were undertaken for molecular test by PCR-RFLP method for confirmation and genotyping of samples. The test preference was compared between sickling and solubility test by setting four criteria; cost, time, reliability and field-based feasibility. Total 386 samples were collected from eight sub-ethnic groups of Tharu ethnic group. Both male and female from different nine municipalities of Rupandehi participated in this study. Out of them, 67 were found to be positive for sickling test and 68 for solubility test. Total 69 positive samples from these two methods were prescribed for molecular test and out of them two were found to be homologous dominant(AA), 57 heterogeneous(AS) and remaining 10 recessive for sickle cell trait. Kanwar Tharu showed highest prevalence(53.94%), Dadaha 46.87%, Kathariya 18.40%, Khausiya 9.52%, Dangoriya 6.94%, Baatar 6.09% and Marchaha Tharu showed lowest prevalence with no occurrence of sickle hemoglobin. The genotype frequency was found 82.64%, 14.77% and 2.52% for wild, hetero and mutant respectively. The allele frequency of HbA and HbS was 0.9 and 0.1 respectively. Out of three methods, sickling test was found to be cheapest, short time-consuming, reliable and field-based method for screening of Sickle Cell Disease. The prevalence of sickle cell allele is not common in Tharu people of Rupandehi district, Nepal, χ 2 (2, N = 386) = 686.389, p < .00001). The distribution of sickle cell allele is cast dependent,χ2 (7, N = 386) = 58.3823, p < 0) and Kanwar Tharu and Dadaha Tharu are most severely affected sub-ethnic groups with nearly 50% occurrence of HbS allele in their gene pool. The sickling test is cost-efficient and reliable field-based method for mass screening of sickle hemoglobin in the blood.