SCR correlated significantly with higher vaso-occlusive crises (VOC) frequency (ρ = 0.379, p < 0.001), lower fetal hemoglobin (HbF) (ρ = -0.363, p = 0.001), older age (r = 0.295, p = 0.006), and glucose-6-phosphate dehydrogenase (G6PD) deficiency (ρ = 0.428, p < 0.001). This evidence concerns the gene G6PD and G6PD deficiency.