Liver Detox Genes – CYP3A

This is part of an ongoing series on the genes involved in detoxification.

The CYP3A genes (which code for enzymes of the same name) is a subfamily of CYP 450 and is involved in the metabolism of about half the drugs on the market today as well as other xenobiotics and steroids.  There are several major genetic polymorphisms in the CYP3A family that can play a role in how a person reacts to a medication.  Additionally, this is another enzyme that can be influenced by drug interactions as well as some foods.

Several fruits – grapefruit, noni, pomegranate – are potent inhibitors of CYP3A4.  Eating or drinking these can cause adverse effects on drug metabolism – either increasing the effect of the drug or decreasing the effect.

Interestingly, CYP3A4 is naturally more active in women than in men.   A long list of drugs metabolized by CYP3A4 is available on Wikipedia.

Check your 23andMe results for rs4987161:

  • GG:  CYP3A4*17, lower function of enzyme, [ref] [ref]
  • AG: carrier of on e CYP3A4*17 allele
  • AA: normal

 

Check your 23andMe results for rs4986909:

  • AA:  CYP3A4*13, lower function of enzyme, [ref]
  • AG: carrier of on e CYP3A4*13 allele
  • GG: normal

 

Check your 23andMe results for rs2740574:

  • CC:  CYP3A4*1B, increased risk of ovarian and prostate cancer
  • CT: carrier of on e CYP3A4*1B allele
  • TT: normal

 

CYP3A5 is another enzyme that is found in the liver, prostate, and intestines.  It metabolizes several types of drugs as well as testosterone, progesterone, and androstenedione.  There are several polymorphisms that reduce the activity of this enzyme significantly. [ref]

Check your 23andMe results for rs41303343:

  • AA:  CYP3A5*7, non-functional
  • -A: carrier of on e CYP3A5*7 allele
  • II: normal

 

Check your 23andMe results for rs28365083:

  • TT:  CYP3A5*2, non-functional
  • GT: carrier of on e CYP3A5*2 allele
  • GG: normal

 

Check your 23andMe results for rs776746:

  • CC:  CYP3A5*3, non-functional
  • CT: carrier of on e CYP3A5*3 allele
  • TT: normal

 

Check your 23andMe results for rs55817950:

  • AA:  CYP3A5*8, non-functional
  • AG: carrier of on e CYP3A4*8 allele
  • GG: normal

 

Check your 23andMe results for rs28383479:

  • TT:  CYP3A5*9, non-functional
  • CT: carrier of on e CYP3A4*9 allele
  • CC: normal

 

Check your 23andMe results for rs41279854:

  • GG:  CYP3A5*10, non-functional
  • AG: carrier of on e CYP3A4*10 allele
  • AA: normal

 

Check your 23andMe results for rs56244447:

  • CC:  CYP3A5*3D, non-functional
  • AC: carrier of on e CYP3A4*3D allele
  • AA: normal

 

 

Comments 2

  • Hi Debbie,

    I really like your blog, but please check if you got rs776746 the wrong way around. I think CC (GG) might be the non-expressor (CYP3A5*3 homozygote).

    Regards,

    Leon

    • Hi Leon – Sorry to take so long to respond to your comment on my blog. I do appreciate you reading the blog, and I really appreciate you letting me know that I had the description on those alleles flipped around!
      Debbie

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