Gene Therapy for HbSC Disease and other Compound Heterozygous Sickle Hemoglobinopathies: A Time for Inclusion Available to Purchase

Two gene therapy products have been FDA approved for sickle cell disease. Nearly all patients in the clinical trials that led to approval were either sickle hemoglobin gene homozygotes (sickle cell anemia) or had HbS-β0 thalassemia. HbSC disease, caused by compound heterozygosity for HbS and HbC genes, is the second most common genotype of sickle cell disease. Gene therapy has not been tested in HbSC disease patients who are severely symptomatic. We discuss the pathophysiology and clinical features of HbSC disease, and how gene therapy is likely to provide a curative option for some individuals. We also discuss the mechanism through which HbF and HbF-like HbA (HbAT87Q) might mitigate adverse clinical outcomes and end-organ damage in HbSC disease and other compound heterozygous sickle hemoglobinopathies.