Neve et al. documented significantly higher mean copper levels in the erythrocytes, but not in plasma, in cystic fibrosis patients (3.56 μg/g Hb ± 0.50) as compared to healthy age-matched controls (2.73 μg/g Hb ± 0.30) [82]. This evidence concerns the gene GSTM1 and cystic fibrosis.