rs2279343

A SNP in the CYP2B6 gene on chromosome 19. Its most notable genotype is G;G: Lower doses of efavirenz for treating HIV may be recommended

Gene
CYP2B6
Location
Chr 1941,009,358 (GRCh38)
Highest magnitude
2.0Worth knowing
Tested on
23andMe, AncestryDNA

Genotypes

As shown in 23andMe and AncestryDNA files.

  1. A;AGoodcommon in clinvarTypical · 0.0
  2. G;GMost notableBadLower doses of efavirenz for treating HIV may be recommendedWorth knowing · 2.0

On SNPedia: (A;A), (G;G). Magnitude rates how notable a genotype is from 0 to 10, not how risky it is.

Conditions, medicines and genes

Other CYP2B6 SNPs

All CYP2B6 SNPs

Notes

From SNPedia

Show notes, about 180 words

rs2279343, also known as c.785A>G, p.Lys262Arg and K262R, is a SNP within the CYP2B6 gene. associated with response to efavirenz variants including the Arg allele include CYP2B6*4, CYP2B6*6, and CYP2B6*7 Pharmacokinetics of efavirenz when co-administered with rifampin in TB/HIV co-infected patients: pharmacogenetic effect of CYP2B6 variation. Polymorphisms of drug-metabolizing enzymes (GST, CYP2B6 and CYP3A) affect the pharmacokinetics of thiotepa and tepa. Associations between CYP2B6 polymorphisms and pharmacokinetics after a single dose of nevirapine or efavirenz in African americans. CYP2B6 variants and plasma efavirenz concentrations during antiretroviral therapy in Port-au-Prince, Haiti. Cyclophosphamide-metabolizing enzyme polymorphisms and survival outcomes after adjuvant chemotherapy for node-positive breast cancer: a retrospective cohort study. CYP2B6 polymorphisms influence the plasma concentration and clearance of the methadone S-enantiomer.

G;G

see rs2279343; poor metabolizer of efavirenz may cause CNS toxicity if given normal doses as part of HIV treatment regimen

Source and license

Adapted from rs2279343 on SNPedia, using a snapshot taken October 16, 2026. SNPedia content is shared under CC BY-NC-SA 3.0 US, and this page is shared under the same license.

SNPedia is a community-edited wiki. Its entries can be incomplete, out of date or wrong, and nothing here is a diagnosis or medical advice. Magnitude is a community rating of how interesting a genotype is, not a risk score.