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Interesting COMT Variations

Discussion in 'Genetic Testing and SNPs' started by Valentijn, Aug 10, 2013.

  1. Valentijn

    Valentijn Activity Level: 3

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    Instead of "risk", as used thus far in other methylation lists, I'm marking the slower versions. The reason for this is because slow and fast COMT genes each have different medical risks, but for the purposes of methylation, it's the slow versions which can make things trickier, as the slow versions may result in reduced tolerance of methyl groups in supplements.

    "Implied" slow alleles are based on studies where novelty seeking is associated the other allele, as novelty seeking has been associated with up-regulation. I'm not as confident in those sorts of studies, as they're basically making a lot of assumptions based on questionnaires and interpretations of behavior. Two haplotypes are listed at the end. These are only relevant when all of the alleles are present.

    SNP names are underlined, bolded, and orange when they indicate a missense mutations. Rare missense mutations lacking research have a "?" after the rare allele, as it's not known if that rare allele is a down-regulation or an up-regulation.

    rsID.........NAME....SLOWER...ETC
    rs737866.....T689C...C.......Implied
    rs737865.....A701G...G
    rs4646312....T385C...T.......Implied
    rs165722.....C201T...C.......Implied
    rs6269.......A98G....A
    rs6270.......C34S....C?
    rs4633.......H62H....TT
    rs6267.......A72S....T
    rs13306281...V92M....A?
    rs61910731...V100L...T?
    rs5031015....A102T...A?
    rs4986871....A146V...T?
    rs4680.......V158M...AA.....1/3 activity
    rs13306279...P199L...T?
    rs174696.....C1354T..C.......Implied
    rs9332377....C367T...T
    rs165599.....G522A...G

    Haplotype I (only relevant when all of these versions are present):
    rs4646316....C310T...C
    rs9332377....C367T...T

    Haplotype II (58-fold reduction in function when all of these versions are present):
    rs6269.......A98G....A
    rs4633.......H62H....C
    rs4646312....T385C...T......See Note
    rs4680.......V158M...G

    Note: rs4646312 in Haplotype II is reported with the more common allele of rs4818 as the risk factor. 23andMe doesn't contain that SNP, but rs4646312 has identical and nearly identical prevalence rates in the various groups genotyped, hence is likely usually inherited in a "chunk" with rs4818. So the results of rs4646312 will usually be applicable, but might not be in some cases.
     
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  2. Valentijn

    Valentijn Activity Level: 3

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    So what is COMT and why is it worth discussing in the context of methylation?

    Basically it's involved in the breakdown of some neurotransmitters, and when those neurotransmitters break down, they use a methyl group in the process. Thus someone with faster COMT will use up more methyl groups and have a greater tolerance for supplements involving methyl groups, such as methylfolate and methylB12.

    Conversely, someone with slower COMT won't be using up methyl groups as quickly, and might need to be careful about adding too many into the mix via supplementation.

    PS - I really hate this gene. It's one huge mess, with a ton of research to sort though. And too much of it reminds me of the "this personality type is associated with developing CFS" BS :mad:
     
  3. Sea

    Sea Senior Member

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    NSW Australia
    Are you sure of the alleles for haplotype 2 Valentijn? Rs4633 is listed with T as the slower version in the top list but with C as the version for the haplotype.
     
  4. Valentijn

    Valentijn Activity Level: 3

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    Yup. A lot of things change quite a bit in haplotypes.
     
    Sea likes this.
  5. So I have :
    rs4680.......V158M...AA.....1/3 activity

    Do I lose 1/3 activity or only have 1/3 activity. Is this why I appear to be tolerating methyl groups?

    I also have H62H TT

    thanks
     
  6. Critterina

    Critterina Senior Member

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    Arizona, USA
    Valentijn,

    I really like all the work you do and post like this. I saw the rare MTHFR and this one. Have I missed any?

    I tolerate methyl groups very well, so no surprise that my only result was

    COMT...rs165722.....C201T...C.......Implied +/+

    Thank you!
     
  7. Valentijn

    Valentijn Activity Level: 3

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    AA has one-third of the activity as the other homozygous genotype for the SNP. So it's running at 33%. But that's not necessarily saying that AA is "too slow", just that it's slower than than the other version, which might just as easily be considered "too fast".

    H62H probably has less of an impact than V158M, since H62H isn't a missense or other mutation resulting in a change in the structure of the gene.

    There's probably a lot of factors that go into tolerating methyl groups, and frankly I haven't see any proof that slower COMT results in less tolerance of methyl groups - but I also haven't looked, and it does make some sense in theory at least.
     
  8. Hey!
    What did you use that reported the above? Just intrigued. rs165722 TT is listed in my 23andme full genome list, but then not reported from livewello - just wondered if I'm missing anymore (although struggling to keep up with the ones that I have!)
     
  9. Valentijn

    Valentijn Activity Level: 3

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    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2724734/ , specifically Table 6.
     
  10. Creekee

    Creekee Senior Member

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    Thanks for all the info, Valentijn! I am a bit COMT confused here. Genetic Genie says:

    COMT V158M AA +/+
    COMT H62H TT +/+
    COMT P199P AG +/-


    Started a methylation protocol for the first time in early March. Ever-tweaking, but so far unable to trigger any over-methylation.

    I do have +/+ VDR Taq. Maybe that's compensating some?

    Really appreciate all the research you're sharing. So interesting!
     
  11. musicchick581

    musicchick581 Senior Member

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    In haplotype 2, I have all of those but I have heterozygous risk alleles, ex.

    rs4680, you say G is a slower COMT, well I have AG. I have that pattern for all of those under haplotype 2. Does this mean I don't have the 58 fold reduction? Do they have to be homozygous?
     
  12. Valentijn

    Valentijn Activity Level: 3

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    No idea ... the research never specifies that when they're looking at haplotypes.
     
  13. taniaaust1

    taniaaust1

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    Sth Australia
    I thought I'd put the following link here rather then starting a new COMT thread . I just come across the following and thought it may be of interest to some who have COMT mutations http://www.mayomedicallaboratories.com/test-catalog/Clinical and Interpretive/83301 (sorry if this is already here somewhere).

    For those who dont know terms.. the term "wild type" is refering to anyone who doesnt have a mutation.

    All the below info is out of the link I put before.

    COMT Allele
    Amino Acid Change
    Effect on Enzyme Activity/Metabolism

    *1
    None (wild-type)
    Normal/Extensive
    *2
    Val108/158Met
    Reduced/Poor
    *3
    Ala52/102Thr
    Reduced/Intermediate

    Drugs that undergo metabolism by COMT:

    -Alpha-methyl DOPA
    -Apomorphine
    -Benserazide
    -Bitolterol
    -Dihydroxyphenylserine
    -Dobutamine
    -Dopamine
    -Epinephrine
    -2-Hydroxyestrogens
    -4-Hydroxyestogens
    -Isoetherine
    -Isoprenaline
    -Isoproterenal
    -Norepinephrine
    -Rimiterol

    Coadministration may decrease the rate of elimination of other drugs metabolized by COMT.

    Drugs that undergo structural modification but are not metabolized by COMT:

    -Albuterol
    -Metaproterenol
    -Methoxamine
    -Phenylephrine
    -Perbuterol
    -Terbutaline

    Coadministration will not decrease the rate of elimination metabolism of other drugs metabolized by COMT.

    Drugs known to inhibit COMT activity:

    -Entacapone
    -Tolcapone
    -Nitecapone

    Dietary Components that inhibit COMT activity:

    -Quercetin
    -Tea catechins

    Coadministration will decrease the rate of metabolism of COMT metabolized drugs, increasing the possibility of toxicity, including in heterozygous individuals.
     
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  14. Leon

    Leon

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    @Valentijn

    I hoped you could help clear up some confusion. I am homozygous for both SNP's, and assume therefore I'm working slowly (H62H) + 1/3 of slowly (V158M). But I don't understand how to interpret the V158M by reference to the H62H in real terms. How can we describe H62H as "too fast" in any sense if we are homozygous for the "slower" H62H genotype? Surely, we are just running slowly.

    I also don't really understand how we are able to compare V158M by reference to H62H when H62H may have less of an impact that V158M, because it isn't a missense or other mutation? I'm left wondering what 1/3 of the activity of H62H means in practice. :thumbdown: Perhaps the most useful genotype is V158M? If you're homozygous for this, you can reasonably assume that methyl donors could prove problematic - or at least tread carefully, bearing in mind there are those mutations, such as rs13306279...P199L...T?) for which there is no reliable evidence that it's an up- or down-regulation).

    Any thoughts would be great!
     
  15. Valentijn

    Valentijn Activity Level: 3

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    I meant that being homozygous for the "slow" version doesn't necessarily mean that you're running slow. You could just as well think of it as running at "normal" speed, which people homozygous for the opposite version are "fast". There's really not any indication that the fast or slow version is at all abnormal, hence having the "slow" (or normal?) version isn't anything to get worried about "treating".

    H62H and V158M look like they're in complete linkage disequilibrium - so if someone is +/+ for one, they're almost always +/+ for the other. Hence any research linking H62H to different gene function is probably a bit of a false positive, and it really is just showing an association due to study participants having the identical version of V158M. So H62H is useless for determining gene function, unless you don't have access to your V158M alleles.
     

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