Although we previously observed significant, independent associations of both higher hemolytic index and lower hemoglobin oxygen saturation with elevated tricuspid regurgitation velocity in this cohort of children and adolescents with sickle cell disease [6], the present study indicated that the hemoglobin oxygen saturation was not significantly associated after adjustment for VEGF, PDGF-BB and interleukin-6. This evidence concerns the gene VEGFA and sickle cell disease.