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Pharmacogenetics: CYP2C19 Genetic Polymorphisms


    Single Nucleotide
     CYP2C19*1  General Population
     Wild-type; 50,720bp  10q24.1-3  Normal  Extensive metabolizer
     CYP2C19*2  2-5% Caucasians
     18-23% Japanese
     40bp deletion
     Exon 5
     ↓  Poor metabolizer
     CYP2C19*3  13% Islands of
     W212X(636G→A)  Exon 4
     ↓  Poor metabolizer;
     premature stop codon
     CYP2C19*4  0.6-3% Caucasians
     M1V (Mutation in
     initiation codon
     ↓  Poor metabolizer,
     Defect in initiation
     CYP2C19*5  Low in both Chinese
     & Japanese
     R433W (1297C→T)  Exon 9  ↓  Poor metabolizer
     CYP2C19*17  18% Ethiopians
     & Swedes,
     1.3% Japanese,
     0.64% Chinese
     C806T (3402C→T)
     ↑  Ultra-rapid metabolizer
     Increased 2C19 gene

    Note: A = adenine (nucleotide), C = cystine (nucleotide), G = guanine (nucleotide), M = methionine (amino acid),
    R = arginine (amino acid), T = thymine (nucleotide); V = valine (amino acid); W = tryptophan (amino acid); X = termination codon.
    1. Meier UT, Meyer UA.  Genetic polymorophism of human cytochrome P-450 (S)-mephenytoin 4-hydroxylase: studies with human autoantibodies suggest a functionally altered cytochrome P-450 isoenzyme as cause of the genetic deficiency.  Biochemistry  1987;26:8466-8474.  PubMed
    2. De Morais SMF, Wilkinson GR, Blaisdell J et al.  Identification of a new genetic defect responsible for the polymorphism of (S)-mephenytoin metabolism in Japanses.  Molec Pharmacol  1994;46:594-8.  PubMed
    3. De Morais SMF, Wilkinson GR, Blaisdell J et al.  The major genetic defect responsible for the polymoprhism of S-mephenytoin metabolism in humans. J Biol Chem 1994;269:15419-15422.  PubMed
    4. Kaneko A, Kaneko O, Taleo G et al.  High frequencies of CYP2C19 mutations and poor metabolism of proguanil in Vanuatu. Lancet  1997;349:921-2.  PubMed
    5. Ferguson RJ, DeMorais SMF, Benhamou S et al.  A new genetic defect in human CYP2C19: mutation of the initiation codon is responsible for poor metabolism of S-mephenytoin.  J Pharmacol Exp Ther  1998;284:356-361.  PubMed
    6. Sim SC, Risinger C, Dahl ML et al.  A common novel CYP2C19 gene variant causes ultra-rapid drug metabolism relevant for the drug response to proton pump inhibitors and antidepressants.  Clin Pharmacol Ther  2006;79:103-113.  PubMed
    7. Sugimoto K, Uno T, Yamazaki H et al.  Limited frequency of the CYP2C19*17 allele and its major role n a Japanese population.  Br J Clin Pharmacol  2008;65:437-39.  PubMed

Editors & Reviewers

  • Editors:  Anthony J. Busti, MD, PharmD, FNLA, FAHA
    Last Reviewed:  June 2015

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