Sickle Cell Gene Frequency Analysis in Visapur, District Chandrapur: A Case Study of Single Village from Central India

Abstract

Sickle cell anemia burden is generally studied by calculating how many sickle cell carriers are found in specific diagnostic camps based on combination of screening test and confirmatory tests i.e. sickle cell carrier prevalence method. Where as actual total numbers of alleles can be estimated by combining data of how many carriers and homozygous patients are found in the confirmatory testing camps, which is a gene frequency calculation method. Aim of this study is to compare prevalence and gene frequency calculations for one village data, for study conducted in year 2005 at Visapur village, Chandrapur district, Central India. Sampling was done in village school followed by screening and confirmatory testing at field work laboratory at Ballarpur city which included solubility test, hemoglobin estimation, hemoglobin electrophoresis using cellulose acetate membrane method followed by pedigree analysis after parent studies. This is a sickle cell anaemia study of single village data point. Out of total population of the village, 6.68% population were randomly studied. Total registrations done for 755 individuals and out of that total 628 individuals were tested (N = 628, 293 were females and 335 were males) for solubility tests followed by haemoglobin electrophoresis. For socioeconomically disadvantages groups, it was noted that out of 628 individuals, tribals were 111 and non-tribals, 517. Out of total tested, N=628, SCD homozygous status were found in 7 cases (Hb S+S electrophoresis pattern). In 87 cases sickle cell carrier status (Hb A+S electrophoresis pattern) were observed and in remaining 534 individuals, non-sickle cell status observed i.e. Hb A+A electrophoresis pattern. Based on this sickle cell prevalence observed for total tribal and non-tribal is 13.85% After classifying tribal Vs non-tribal population, 7 homozygous patients were found in non-tribal communities, 5 in Schedule caste, 1 in OBC and 1 in open category, there is no SCD patient found in tribal community. Out of 50 sickle cell carriers, 7 were found from tribal community and remaining all 80 belongs to non-tribal community. Out of which, 49 are from scheduled cast and 31 from OBC community. After studying sickle cell prevalence and gene frequency pattern, it is found that gene frequency gives more accurate status of sickle cell anaemia even in small population size, i.e. independent study of single village, as compared to estimation sickle cell anemia using sickle cell carrier prevalence method.