GSTM1 and sickle cell disease: These frequencies vary widely according to the degree of racial admixture in the different regions of Brazil.10 Since the data from the municipal Health Department of Uberaba show that the prevalence of sickle cell disease in the region in 2012 was 1:1166, the high rate observed in the current study may be due to the small sample size and also to the fact that one of the infants with Hb SS was from a neighboring town (Delta).