Examples of Important Genetic Polymorphisms

CYP2D6 Alleles Causing Absent or Decreased Enzyme Activity 

FIGURE 13.4 Distribution of the urinary debrisoquine/4-hydro)9 debrisoquine metabolic ratio (MR) in 695 Cliinese and 1011 Swedish healthy individuals. The arrows indicate MR = 12.6, the antimode between EMs and PMs established in Caucasians. A line is drawn at MR = 1. Most Chinese EMs have MR 1, while most Swedish EMs have MR 1. (Reproduced with permission from Bertilsson L et al. Clin Pharmacol Ther 1992 52 388-97.) 

TABLE 13.3 Frequency of Normal CYP2D6 1 or 2 Alleles and Some Alleles Causing No or Deficient CYP2D6 Activity in Three Different Populations  

CYP2D6 alleles Functional mutation Consequence Allele frequency (%) Swedish Chinese Zimbabwean  

FIGURE 13.5 Distribution of the debrisoquine MR in tliree genotype groups related to the CYP2D6 10 allele in 152 Korean individuals. Wild type (Wt) = CYP2D6 1 (or 2) and mutant (MUT) = CYP2D6 20. (Reproduced with permission from Roh HK et al. Pharmacogenetics 1996 6 441-7.) 

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