CYP1A2 and chronic kidney disease: Comparing organ donors and the patients with end-stage renal disease, significant differences were observed in the proportion of subjects expressed CYP mRNA at low, normal and high levels (Chi2 for CYP1A2: 40.2, for CYP2C9: 87.9, for CYP2C19: 47.2, for CYP3A4: 29.9; df = 2, p < 0.0001) (Fig. 2b).