Screening for the sickle cell gene in Chhattisgarh state, India: an approach to a major public health problem.

The aim of this study is to determine the feasibility of large-scale population screening for the sickle cell gene in high risk areas with limited resources. A programme designed to detect the sickle cell trait and sickle cell disease has screened 359,823 subjects among 2,087 (99.7%) of the villages in Raipur District, Chhattisgarh State, India between October 2007 and June 2010. Children aged 3-15 years were initially screened in the villages by solubility tests on fingerprick samples. Venipuncture was performed on subjects with positive solubility tests, and the samples were transferred to Raipur Medical College for alkaline haemoglobin electrophoresis. The sickle cell trait occurred in 33,467 (9.30%) and an SS phenotype in 747 (0.21%). The gene frequencies were not in Hardy-Weinberg equilibrium most likely due to a deficiency of the SS phenotype failing to enter the sampled population from either sickness or early death. Subjects with abnormal haemoglobin genotypes may factor this information into decisions regarding marriage and avoid the risks of having children with sickle cell disease. The techniques described may be a model for other developing societies with limited resources.