There are numerous examples of subpopulations with altered CYP levels, to mention a few: Obese have reduced CYP3A activity with increasing bodyweight4; Pregnant have increased activity of CYP2D6 and CYP3A4 and reduced CYP1A2 activity5; Individuals suffering from cirrhosis have markedly reduced activity of CYP1A2 and CYP3A4.6 The gene discussed is CYP1A2; the disease is Cirrhosis.