Liver Detox Genes – CYP2C19

Liver DetoxGenesThis is part of an ongoing series of posts about the CYP450 enzymes and detoxification.

The CYP2C19 enzymes are responsible for the breakdown of several popular drugs including some proton pump inhibitors (Prilosec, Nexium, Prevacid), anti-epileptics, and antiplatelet drugs (Plavix). There is a list on the Wikipedia page for CYP2D19.  CYP2C19 is also involved in activating and breaking down some hormones such as progesterone.

There are polymorphisms of CYP2C19 that cause some people to be poor metabolizers and some to be fast metabolizers of these drugs.   Approximately 10 – 20% of Asians are poor metabolizers, as are 2 – 5% of people of Caucasian descent.  I’ve included the more common polymorphisms below, but you can also check on SNPedia for more information on rare mutations.

Check your 23andMe results for rs4244285:

  •  AA:  non-functioning, known as CYP2C19*2
  •  AG :   poorer metabolizer
  •  GG:  Normal    [ref]


Check your 23andMe results for rs4986893:

  •  AA: poor metabolizer, known as CYP2C19*3
  •  AG :   slow metabolizer
  •  GG:  Normal    [ref]


Check your 23andMe results for rs12248560:

    •  CC: normal
    •  CT : ultrafast metabolizer, CYP2C19*17, more likely to benefit from tamoxifen treatment
    •  TT: ultrafast metabolizer, CYP2C19*17 , more likely to benefit from tamoxifen treatment [ref]

OK, so now that you know that you are either a normal, poor, or extensive metabolizer of drugs affected by CYP2C19, what do you do with this knowledge?  Talk to your doctor if you are taking anything that is affected by this gene.

So for a person not on any drugs, what does the CYP2C19 gene do?   It is involved (minor) in metabolizing melatonin.  [ref] and is also involved in the metabolism of progesterone.

More to come in the next few weeks on the CYP450 polymorphisms.

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