GSTM1 and thalassemia: With regard to thalassaemia specifically a study by May et al.,43 showed that gene transfer using a LV that contained proximal and distal regulatory elements with a large segment of the LCR (TNS9) could correct β-thalassaemia in mice, with an average increase in Hb by 3–4g/dL per vector copy and improvement of haematological indices.