Prevalence of the β^SGene Among Scheduled Castes, Scheduled Tribes and Other Backward Class Groups in Central India

Abstract

Sickle cell disease is an inherited disorder of the blood, and characterized by vasoocclusive crises (VOC), risks for pneumococcal infections and organ toxicities, is associated with morbidity and premature mortality. India, with a population of 1.2 billion individuals, is estimated to be home to over 50.0% of the world's patients with sickle cell disease. The β(S) gene [β6(A3)Glu→Val; HBB: c.20A>T] has the highest prevalence in three socio-economically disadvantaged ethnic categories: the Scheduled Castes (SC), the Scheduled Tribes (ST), and Other Backward Class (OBC) groups in India. The tradition of endogamy practiced by the ethnic groups in India provides the rationale for the screening of individual populations to better understand the distribution of the β(S) gene, guide counseling and awareness programs and aid development of public policy. We undertook a study to describe the prevalence of the β(S) gene in these ethnic groups in the district of Nagpur, Maharashtra in Central India. Through community screening and subsequent targeted screening of high risk individuals, 35,636 individuals were screened, of whom 5466 were found to have sickle cell trait and 1010 were identified with sickle cell disease. Community screening revealed a sickle cell trait prevalence of 13.0% in the SC, 12.0% in the ST and 3.4% in the OBC population. This study describes the prevalence of the β(S) gene within these groups in Central India determined by large scale community screening. This program has uncovered previously undiagnosed cases, provided detailed information to guide population-based disease counseling, prevention and comprehensive care programs.

Clinical events in a large prospective cohort of children with sickle cell disease in Nagpur, India: evidence against a milder clinical phenotype in India

“…Together, the SC (1,108 castes, 16.6% of the population), ST (744 tribes, 8.6% of the population), and OBC (5,013 castes, 41% of the population) are a diverse group of endogamous communities that constitute a substantial proportion of India's population . Extensive studies of the population distribution of the β s gene in India indicate that it is most prevalent in the ST population, but is also prevalent in many SC and to a lesser extent, OBC populations . Community screening studies for SCD have previously described the distribution of β s in the SC, ST, and OBC populations in Nagpur …”

“…32 Extensive studies of the population distribution of the s gene in India indicate that it is most prevalent in the ST population, but is also prevalent in many SC and to a lesser extent, OBC populations. 5,8,[11][12][13][14][15][16]20,21,33,34 Community screening studies for SCD have previously described the distribution of s in the SC, ST, and OBC populations in Nagpur. 31,34,35…”

The spatial epidemiology of sickle-cell anaemia in India

“…First, the precision of a model-based map and estimates are determined by the available data, which is non-randomly distributed. Second, the categorisation of ethnic groups into two categories is reductionist; even within the groups, there is extensive heterogeneity in β S allele frequencies 22 , 34 . The inclusion of more specific ethnicities in the analysis would have resulted in a more tailored map and estimates; however, detailed data on the distribution of all ethnic groups in India are limited.…”

Identification of the hot-spot areas for sickle cell disease using cord blood screening at a district hospital: an Indian perspective

“…With a population of over 1.25 billion individuals, it is estimated that India is home to over 50 % of the world's sickle cell disease (SCD) patients (Shrikhande et al 2014;Kate and Lingojwar 2002). As per the hospital data, the prevalence of sickle gene is found to be 0-18 % in north eastern India, 0-33.5 % in western India, 22.5-44.4 % in central India, and 1-40 % in southern India (Gorakshakar 2006).…”

“…As per the hospital data, the prevalence of sickle gene is found to be 0-18 % in north eastern India, 0-33.5 % in western India, 22.5-44.4 % in central India, and 1-40 % in southern India (Gorakshakar 2006). Sickle cell is specifically prevalent in some ethnic groups because they have practiced or are practicing endogamy (Shrikhande et al 2014).…”