The rs766432 SNV in BCL11A is associated with HbF concentration in asymptomatic carriers (HbAS) individuals of African descent. Graphics show the correlation between genotype and HbF concentrations in nine HbAS and three HbAA individuals of African descent. The lines of the boxes represent the lower quartile, the median, and the upper quartile, respectively. a/a = Homozygous, individual for alleles with the lower frequency. A/a = heterozygous individual. A/A = Homozygous individual for alleles with the highest frequency. The correlation between the categorical qualitative variable (genotype) and a quantitative variable (HbF concentration) was evaluated by Spearman’s correlation = ρ (rho).  = statistically significant difference.