Genomic ancestry evaluated by ancestry-informative markers in patients with sickle cell disease

The β(s) mutation is responsible for the most aggressive form of sickle cell disease, has a predominantly African origin, and arrived in Brazil through the slave trade. However, the Brazilian population is highly miscegenated, underscoring the importance of ancestry-informative markers (AIMs) for the identification of the genetic structure of a population. In this study, we have estimated the genetic contributions of various ethnicities in individuals with sickle cell disease in the microregion of Jequié, Bahia, in Brazil, by using AIMs, and compared the findings to those from a phenotypic characterization. Eight AIMs were analyzed: AT3 (rs3138521), DRD2 (rs1079598), APO (rs3138522), PV92, Sb19.3 (rs3138524), CKM (rs4884), LPL (rs285), and CCR5Δ32 (rs333). Samples were subjected to polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism. The amplified products were electrophoresed on agarose gels, and the data were statistically analyzed using Genepop, FSTAT 2.9, and Admix3. Phenotypic classification showed a high frequency of mulattos  (85%) in the Brazilian population; however, ancestry-informative markers indicated that 44, 42, and 11% of the population had European, African, and native American ancestries, respectively. The phenotypic classification is justified as a complementary method for the characterization of the genetic ancestry in patients with sickle cell disease, as it confirms the molecular findings regarding ancestry.