Sickle Cell Disease — Genes & Biomarkers Biomarker / Gene Bad Score Free Actions Non-free Interventions GENES HBB (β-globin) HbSS genotype Hydration, avoid cold/stress Hydroxyurea, gene therapy BCL11A Low expression CRISPR gene editing HBG1 / HBG2 Low γ-globin activity HbF-inducing agents BIOMARKERS HbS (%) >85% Hydration, avoid triggers Exchange transfusion HbF (%) <5% Hydroxyurea, voxelotor WBC count >15 G/L Avoid infections Antibiotics, vaccines LDH Elevated Rest, hydration L-glutamine, crizanlizumab Bilirubin Elevated Hydration Cholecystectomy (if stones)