Based on low MCV <76fL and MCH<25 pg, in the presence of elevated A2 >4.0% on HPLC and Hb variants eluting outside the S and C windows, at least four haemoglobin phenotypes (SS: 87.7%; SC: 1.1%; SD Punjab: 0.6%; Sβ-thalassemia: 10.6%) were identified. This evidence concerns the gene GSTM1 and thalassemia.