GSTP1 and type 2 diabetes mellitus: Gönül et al. in Turkish patients found that carriers of combined GSTM1 null and GSTT1 null, associated with a complete lack of enzyme activity, and GSTP1 Ile/Val genotype had an increased risk of developing T2DM (OR = 4.118, 95% CI = 1.327–12.778, p = 0.009) [15].