Overall, we found that modest donor chimerism with V5m3-400-transduced HSCs resulted in consistent HbF levels ≥ 20%, a threshold that likely produces substantial therapeutic effects in SCD.21,49–51 Moreover, approximately two-thirds of the gene therapy-treated mice exhibited HbF levels ≥ 30%, which was associated with additional improvements in some clinical parameters including Hb level and splenomegaly. The gene discussed is GSTM1; the disease is Schnyder corneal dystrophy.