They were distributed as follows: 62 homozygous Hb SS patients (30 males with a mean age 18.7 years); 32 females (with a mean age of 21.2 years); 54 sickle/β-thalassemia (39 sickle/β0-thalassemia and 15 sickle/β+-thalassemia) including 21 females (mean 19.2 years) and 33 males (mean 16.4 years); and 35 sickle cell trait individuals, including 21 males (mean 22.4 years) and 14 females (mean 20.9 years). This evidence concerns the gene GSTM1 and thalassemia.