CYP1A2
Cytochrome P450 Family 1 Subfamily A Member 2
Gene Number: 1544
Location: 15q24.1
Key Functions: Caffeine metabolism, drug metabolism, processing compounds in the liver
CYP1A2 produces a liver enzyme that helps break down caffeine and several medicines. Differences in its activity contribute to how quickly the body processes these substances [R].
This report examines rs762551, a common CYP1A2 variant studied for its relationship with caffeine metabolism. It influences how strongly enzyme activity can increase in response to environmental factors, helping explain some of the variation in how people process coffee and other caffeinated drinks (R).
Explore your genotype below. For related reports, visit COMT and catecholamine metabolism or SLCO1B1 and medication transport.
SNP ID | Your Genotype | Alt Allele | Interpretation |
|---|---|---|---|
rs762551 | Analyze your DNA to see your genotype | A | Analyze your DNA to see a personalized result. |
rs762551 — Caffeine Metabolism
AA – Greater enzyme inducibility. Linked to faster caffeine metabolism when CYP1A2 activity is stimulated, particularly in studies of smokers and heavy coffee consumers [R, R].
AC – Lower enzyme inducibility than AA. Linked to slower caffeine metabolism relative to AA under these conditions. Often studied together with CC [R, R].
CC – Lower enzyme inducibility than AA. Linked to slower caffeine metabolism relative to AA under these conditions. CC is not consistently established as slower than AC [R].
Functional effect: rs762551, also called −163C>A, lies in a noncoding region of CYP1A2. It does not change the enzyme’s protein sequence. The A allele has been associated with greater inducibility—the ability to increase enzyme activity in response to certain exposures [R].
What Did the Research Find?
An early study tested 185 nonsmokers and 51 smokers after a 100 mg caffeine dose. Among smokers, AA participants had an approximately 1.6-fold higher caffeine metabolic ratio than AC or CC participants. This ratio measures enzyme activity; it does not mean caffeine cleared exactly 60% faster [R].
A later study found that heavy coffee consumption was associated with increased CYP1A2 activity specifically in people with the AA genotype [R].
Understanding Your Result
Your genotype helps explain caffeine metabolism, but it does not specify how many hours caffeine will remain in your body. Smoking, hormonal contraceptives and some medicines also influence CYP1A2 activity [R].
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