Extensive admixture in Brazilian sickle cell patients: implications for the mapping of genetic modifiers.

This study was developed after approval by the Ethical Committees from the Universidade Federal de Minas Gerais and the Hemominas Foundation. We estimated admixture in unrelated subjects with sickle cell disease (SCD, n = 200) and healthy blood donors (n = 291), sampled across different regions of the state of Minas Gerais (Figure S1), a geographic area in South Eastern Brazil similar to that of France, peopled by more than 20 million inhabitants. The Minas Gerais State had a very important role during the colonization of Brazilian inlands, and several cities were funded during the XVIII Century, when due to an intensive mining activity, this state was the economical center of Brazil.1 The slaves that arrived to Minas Gerais had a diversified African origin: those coming from Rio de Janeiro were mainly from Angola, and those coming from Bahia were mainly from Ivory Coast.2 Admixture studies on healthy individuals from specific locations of Minas Gerais suggest extensive admixture.3,4,5