Gene CYP

There are 2 variants (called allele) of this gene which means that a small section of the CYP1A2 gene has a different nucleotide (building block of nucleic acid) and is marked by A->C substitution at position 734. (1, 2)

Each of us has two copies of the CYP1A2 gene, one inherited from each parent. These different variants are:

• Gene CYP1A2*1A (high activity),
• Gene CYP1A2*1F (low activity)

The resulting combination of these gene variants determines if you are a slow or a fast caffeine metabolizer.

Fast caffeine metabolizers have both fast variants – CYP1A2*1A.

In other words, they are homozygous CYP1A2*1A + CYP1A2*1A (fast variant + fast variant).

Slow caffeine metabolizers have at least one slow variant – CYP1A2*1F.

In other words, they are either homozygous CYP1A2*1F + CYP1A2*1F (slow variant + slow variant) or heterozygous CYP1A2*1A + CYP1A2*1F (fast variant + slow variant). (1, 2, 3)

Please click here to read more on the topic of the impact of genes on caffeine intake.