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MMAB Defect Can Lead to AB12 Deficiency

Discussion in 'Genetic Testing and SNPs' started by Changexpert, Jun 22, 2015.

  1. Changexpert

    Changexpert Senior Member

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    MMAB stands for "methylmalonic aciduria (cobalamin deficiency) cblB type," which is responsible for converting coblamin to AB12. Defects in MMAB SNP's can lead to AB12 deficiency. There is not much evidence on which SNP within MMAB gene upregulate or downregulate AB12 deficiency. However, according to my source (cited below), mutation in this gene can result in AB12 deficiency.

    Looking at my test result, I have homozygous conditions for MMAB G16110A (rs7134594) and MMAB/MVK A-818G (rs12314392). According to 23andme result I have, there are 18 SNP's available for MMAB gene. I am homozygous for 11 of them. This could explain why I would get surge of energy from taking AB12, but of course, more research is needed to assess the phenotype and the expressivity of these genes.

    Source
    http://ghr.nlm.nih.gov/gene/MMAB
     
    Last edited: Jun 23, 2015
    pogoman, merylg and Sea like this.
  2. Sea

    Sea Senior Member

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    NSW Australia
    Off to check my MMAB gene. I don't think it came up before when I researched cobalamin deficiency. Thanks Changexpert
     
  3. Gondwanaland

    Gondwanaland Senior Member

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    Hopefully some of them are -/- rather than +/+!
     
  4. pogoman

    pogoman Senior Member

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    This is good to know, I have 13 homozygous MMAB SNPs in my 23andme report.

    On the G16110A and A-818G mutations do you know their specific SNP?
    I did find some info altho I do could not find out how to identify the SNPs or variants listed in them as being disease related.
    R186W is an example, is it an SNP, variant or something else?
    http://hmg.oxfordjournals.org/content/11/26/3361.full.pdf
    http://www.genecards.org/cgi-bin/carddisp.pl?gene=MMAB
     
  5. Valentijn

    Valentijn The Diabolic Logic

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    Being "homozygous" is completely meaningless. Everyone is homozygous for hundreds of millions of SNPs. It is completely 100% normal!

    In order to determine if a variant of a SNP can cause problems, you have to read the research. Every single time.
     
  6. Changexpert

    Changexpert Senior Member

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    Per @Valentijn's request, original post has been edited. Also, SNP for two specific genes have been added.
     
  7. Gondwanaland

    Gondwanaland Senior Member

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    DH and I are equally homozygous for every single SNP in this gene. I bet (hope) all of them are -/- :balloons: ;)
     
    Anju likes this.
  8. Gondwanaland

    Gondwanaland Senior Member

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    We are CC for this one (probably -/-)

    We are AA for this one (probably -/-)

    I would be more concerned with your +/- ones
     
    sleepingbeautycan likes this.
  9. pogoman

    pogoman Senior Member

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    well I woke up after a few hours of sleep so I dug a bit deeper while waiting to get sleepy again.
    fwiw Iit seems theres 3 types of methylmalonic aciduria (cobalamin deficiency).
    the cblB type connected to the MMAB gene as posted and also the cblA type (MMAA gene) and cblD (formerly cblH) connected with the MMADHC gene.
    I haven't had a chance to read all the links yet, 23andme shows SNPs for each altho alot of the "i" ones for MMADHC.
    http://www.omim.org/entry/251100
    http://www.omim.org/entry/277410
     
  10. sleepingbeautycan

    sleepingbeautycan

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    I looked for the snps related to the first link and they are on this page: http://www.omim.org/allelicVariant/607481 but 23andme didn't test for them (that I could see)

    The second link I could not interpret. I depend on seeing rs# and when I don't I am not sure what to look for.
     
  11. CCC

    CCC Senior Member

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    Would this be a possible explanation for the very large doses of adenosylB12 (and FMN) my son seems to need? We're seeing a positive effect from it: for example, the PTM (post thinking malaise) seems to have fallen away this past week.

    @Valentijn - I've been wondering whether we should go down the genetic testing path to find out whether this is a lifelong thing or just transient (from induced deficiency), but I'm not sure we know enough to make it worthwhile. What's your view?
     
  12. Anju

    Anju

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    Hartford, CT
    Thanks a lot, Gondwanaland, for attaching these very useful Links in your signature.
    With my Heavy BRAIN FOG, Headaches, Depression, etc it will take me a LOOOONG TIME to digest any of it.
    Appreciate your Effort and Sharing !!!
    Now, if i could just have some GUIDANCE for my CONFUSED BRAIN, that would be a MIRACLE !
     
    Last edited: Apr 29, 2016
  13. Valentijn

    Valentijn The Diabolic Logic

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    I would do genetic testing ... obviously, since I did :p But it's important to understand what you get from the testing. 23andMe is sampling dozens of SNPs per gene, or just a few, or not at all, with a very good chance that relevant SNPs are not tested. But something useful might turn up, even if not causing the actual disease or providing an answer to it. If US$99 or US$199 or whatever they charge now isn't a big problem, it an easy way to look for some of the more common pathogenic SNPs.

    Then there's Whole Exome Sequencing (WES), with quality tests down to around US$1000 (without interpretation). There are also gene panels available which sequence entire genes connected to certain health problems, such as B12. But those are going to be about as expensive as WES. And they are more difficult to analyze, unless you pay several hundred dollars for it, though that is something I'm trying to figure out how normal users can do it.

    If your son is young, in his teens or pretty close, there's a good chance he'll recover just by resting and waiting it out. Then it might not make much difference to his health if you have genetic information or not.
     
  14. Gondwanaland

    Gondwanaland Senior Member

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    I have been 3+ years looking into it and keep going...:eek:
     

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