Variant Annotations
PharmGKB variant annotations provide information about variant-drug pairs based on individual PubMed publications. Each annotation represents information from a single paper and the goal is to report the information that the author states, not an interpretation of the paper. The PMID for supporting PubMed publications is found in the "Evidence" field.
Information presented, including study size, allele frequencies and statistics is taken directly from the publication. However, if the author does not correct p-values in cases of multiple hypotheses, curators may apply a Bonferroni correction. Curators attempt to report study size based on the actual number of participants used for the calculation of the association statistics, so the number may vary slightly from what is reported in the abstract of the paper. OMB Race Category information is derived from the paper and mapped to standardized categories. Category definitions may be found by clicking on the "OMB Race Category" link.
There are 3 annotations for this variant. Register or sign in to see them.
VIP Variant in CYP2A6
rs8192726 (1836 G>T) is found within the CYP2A6*9b allele. It has been associated with reduced efavirenz metabolism in a study of 94 individuals, [Article:19779319] or when patients with this variant are combined with those with the CYP2A6*17 allele (rs28399454) [Article:19371316], but not in a smaller study of 50 individuals [Article:20860463]. In multiple regression analysis, incorporating multiple variants, CYP2A6 rs8192726 and/ or rs28399454 status independently contributes to efavirenz inter-individual plasma concentrations, accounting for around 10% (8.6-12%), with CYP2B6 rs3745274 genotype TT contributing 36-45.2%, and UGT2B7 *1a genotype also significantly contributing [Articles:19371316, 19779319].
Please note; several other variants also make up the CYP2A6*9b and CYP2A6*17 alleles, as defined by the CYP-450 nomenclature committee: http://www.cypalleles.ki.se/cyp2a6.htm. See the PharmGKB CYP2A6 haplotype tab for more details.
The CYP2A6 gene is found on the minus chromosomal strand. Please note that for standardization, the PharmGKB presents all allele base pairs on the positive chromosomal strand, therefore the alleles within our variant annotations and haplotypes will differ (in a complementary manner) from those in this VIP summary that are given on the minus strand as reported in the literature.
| Key Publications: |
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Publications related to rs8192726 at chr19:41354496: 3
| Influence of host genetic factors on efavirenz plasma and intracellular pharmacokinetics in HIV-1-infected patients. Pharmacogenomics. 2010. Elens Laure, et al. [Article:20860463@PubMed] | |
| CYP2B6, CYP2A6 and UGT2B7 genetic polymorphisms are predictors of efavirenz mid-dose concentration in HIV-infected patients. AIDS (London, England). 2009. Kwara Awewura, et al. [Article:19779319@PubMed] | |
| CYP2B6 (c.516G-->T) and CYP2A6 (*9B and/or *17) polymorphisms are independent predictors of efavirenz plasma concentrations in HIV-infected patients. British journal of clinical pharmacology. 2009. Kwara Awewura, et al. [Article:19371316@PubMed] |