From SNPedia
| Genotype | Effect |
|---|
| rs12248560(C;C) | normal |
| rs12248560(C;T) | CYP2C19*17 ultra fast metabolizer; drug metabolism effects; also 0.77x decreased breast cancer risk |
| rs12248560(T;T) | CYP2C19*17 ultra fast metabolizer; drug metabolism effects; also 0.77x decreased breast cancer risk |
(T) defines the CYP2C19*17 allele, an ultra fast metabolizer phenotype of the
CYP2C19 gene.
CYP2C19*17 is likely to lead to less effective drug treatment by, for example, proton pump inhibitors (such as omeprazole) and antidepressants.[PMID 16413245]
On the other hand, cancer patients who are CYP2C19*17 carriers are more likely to benefit from tamoxifen treatment, presumably because they break it down more rapidly into the antiestrogenic metabolites endoxifen and 4-hydroxytamoxifen.[PMID 18024866]
A study of 1,000+ breast cancer patients showed a 0.77x decreased risk of breast cancer for carriers of a CYP2C19*17 allele (CI: 0.65-0.93, p = 0.005). Analysis of a subgroup of such carriers who were using hormone therapy for ten years or longer showed an even stronger effect (odds ratio 0.57, CI: 0.39-0.83, p = 0.003). The theory is that ultra fast metabolism of estrogen leads to lower estrogen levels and lower breast cancer risk.[PMID 18521743]
| ? | (C;C) (C;T) (T;T) |
|---|
 |
| PharmGKB | PA161615690 |
| Name | CYP2C19: -806C>T |
| Annotation | This promoter variant is part of CYP2C19*17 haplotype, which causes increased acitivity and increased transcription of CYP2C19. Patients carrying this allele may exhibit a lack of response to commonly prescribed dosages of certain proton pump inhibitors (PPIs) and antidepressants, due to ultrarapid clearance of these drugs. CYP2C19*17 carriers are more likely to benifit from tamoxifen treatment. |
| Gene | CYP2C19 |
| Featue | |
| Evidence | PubMed ID:16413245; PubMed ID:18024866 |
| Drugs | amitriptyline, citalopram, clomipramine, escitalopram, omeprazole, proguanil, tamoxifen |
| Diseases | |
| Curation Level | Curated |
