The volatiles that cause the smells : DIMETHYLSULFIDE and METHANETHIOL .
Enzyme at fault : SELENBP1 .
title : Mutations in SELENBP1, encoding a novel human methanethiol oxidase, cause extraoral halitosis
Pubmed Abstract : link
Full paper : Link
First impressions of this new paper/discovery :
1. IMHO it could be classed as the MOST IMPORTANT METABOLIC BODY ODOR DISCOVERY SINCE THE 'DISCOVERY' OF TMAU IN 1970.
The reason being that the concept of 'metabolic/systemic body odor' has relied on 1 compound (Trimethylamine) to prove the concept and be the 'sole' disorder, so more compounds to the list are welcome.
In a perfect world society would say 'let's now find all the metbo compounds' ... but society is not interested.
2. They feel that the gene to blame is SELENBP1 for this new disorder.
I still suspect FMO3 is to blame, so I will keep an open mind for now.
3. DMS and CH3SH are the compounds to blame for this disorder.
People with 'fecal body odor' (as it's known) complain of smelling of many nasty smells. To me, DMS and CH3SH are far better suspects for causing FBO rather than TMA, and they are probably in my top 5 list of potential FBO smell suspects, so to see them identified is very welcome.
I suspect there may be a few more (probably mostly Volatile Sulfur Compounds, thiols') suspects to add to the list, but I regard these 2 as potentially 'main players'.
My example list of FBO suspects (guesses):
Probably VSCs or Thiols ... e.g.
DMS
Methanethiol
Dimethyldisulfide
H2S
Cysteamine (?)
Way down the list .... TMA
When someone has metabolic BO, the 2 questions are :
1. What compounds are causing the smell ?
2. What enzyme(s) are supposed to neutralize those compounds.
So in this case I think they have identified bigger 'players' of the group of compounds that cause FBO, but wrong enzyme (could be wrong).
The 'urine' test for the new 'metbo disorder' : High Dimethylsulfoxide.
For the urine test they go for DMSO level.
Perhaps DMS and CH3SH are too volatile to rely on in a urine test, and may already have dissipated or altered. They seem to go for the OXIDE of DMS, which is perhaps the natural end product, and judge it on higher levels.
I would suggest this is definitely a test we should take.
About Wevers, Tangerman, Winkel et al :
The paper included the 3 above Drs, as well as many others. They have known to have a long interest in the causes of Halitosis, including metabolic causes.
That said, this paper may have taken 10 years (or more) to publish, so my 2 thoughts on their research are :
1. Whilst I welcome it, I am not relying on any breakthrough in society and Drs knowledge of met BO/hali in the near future.
2. I'm hoping perhaps they have 'stored' research and will announce treatments, test options, as a quickfire bundle of announcements this year, but I'm doubtful.
So in conclusion, my current view is :
Potentially 'top of the list' compounds identified to cause metbo body odor.
For now, I'm still a 'FMO3ist' rather than thinking it is SELENBP1.
Them :
compounds : DMS and CH3SH.
enzyme : SELENBP1
Me :
compounds : DMS and CH3SH (and a few more VSCs, thiols etc).
enzyme : FMO3
Other potential metbo disorders :
I write mostly about my opinion as to the cause of FBO, which seems the main complaint.
I am sure there will be other metbo disorders, but these will be limited to perhaps 1 compound (or a small family), and to other genes.
FBO seems a wide spectrum of smells, so IMHO is most likely a 'broad spectrum' gene, whereas other metbo genes will have a one distinctive smell (probably), such as isovaleric acid.
What compounds make feces smell ?
Everyone knows the smell of poo can vary, so for the most part it seems that the compounds that make the smells are varying too. A guess would be they are mostly VSCs / Thiols, and a few other compound families thrown in. But for the most part they would seem to be sulfur compounds.
It may be a surprise to know the World Scientists do not yet have a definitive list of the compounds that make poo smell. Occasionally a researcher (such as Levitt et al) will do a few papers, but many might disagree with them.
Media links to the story
Gizmodo
Medical Xpress
Science Daily
Genengnews
UCLA press release
4 comments:
I have fbo. No mutations on selenbp1 but do have fmo3 mutations and tested negative.
how do you know re selenbp1 mutation status ?
I see about 6 codons listed in old 23andme, but thats all for now.
what fmo3 mutations do you carry ?
FMO3: c.769G>A (p.V257M)
FMO3: c.472G>A (p.E158K)
is what I see on my genos.co but admittedly I have no idea how to properly check, those are the two that pop up on my report. I can email you if you'd like a more thorough response. also: http://bodyodorresearch.blogspot.com/2017/04/the-body-odor-smell-type.html
right.
I have 158 and 308.
they are the 2 most common, with 257 3rd.
re SELENBP1, just not enough known now I guess. maybe they are claiming this as a new enzyme in humans, or have 'discovered' a role for it.
Most enzymes seem to have very few substrates, whereas FMO3 has a wide range.
Don't know how many substrates SELENBP1 has.
Any theory is possible at this stage.
I would suggest everyone gets their FMO3 DNA checked anyhow, even if just the few codons via ancestry.com etc (probably the common SNPs will be shown in their raw data)
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