This was followed by the first approval of a CRISPR/cas9 HSC therapy, Casgevy, in the treatment of sickle cell disease and transfusion-dependent thalassemia, by targeted disruption of the enhancer regulating BCL11A, a repressor of foetal haemoglobin (Hb) thus inducing functional foetal Hb expression [32]. The gene discussed is GSTM1; the disease is sickle cell disease.