News & Views on Systemic Body Odor and Halitosis such as trimethylaminuria TMAU. If you have fecal odors or bowel odors it may be metabolic/systemic

31 May 2015

New FMO3 paper by Shimizu et al (2015)

New paper by FMO3/TMAU researcher Prof. Shimizu in Japan, and others with a similar research background.

102 people who presumably contacted the lab about a malodor concern were DNA tested for FMO3 faults.
Using their own subjective reference ranges (no consensus on a ref range currently exists), 79 were decreed to have TMAU

The paper seems to be a simple testing of 102 people with a self-reported malodor concern in Japan. Such papers are useful as statistics, and sadly pretty rare. I would say no collection of data on the subject is a tragedy for the community in that the lack of data keeps it regarded as a 'rare' condition.

Of those tested, 79 were 'positive' for TMAU, which hiostorically is quite a high number in such studies. Using my own guess at a reference range, I would expect it to be even higher if not all 102.

Full paper (2015) : TMAU in a Japanese population

The paper wishes to point out the following as important for context :

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Trimethylaminuria results from reduced capacity to convert trimethylamine to trimethylamine N-oxide, a reaction catalyzed by FMO3.
Mutations of FMO3 are known to cause trimethylaminuria, but an understanding of the phenotypic consequences of different FMO3 genotypes (haplotypes) is lacking.

WHAT THIS STUDY ADDS
Severe trimethylaminuria is caused by mutations that severely impair FMO3 activity.
Most affected individuals present with moderate or mild forms of the disorder, due to factors other than FMO3 genotype.
Although for the majority of sufferers sequencing of FMO3 would not be informative, reduction of trimethylamine burden should prove beneficial.

***************

Personally I would strongly disagree with the last point in particular very strongly. Anyone who thinks they may have a metabolic malodor problem should do the FMO3 DNA test. FMO3 and TMAU are not 'intensly researched' subjects where everything is understood about them. To me very little is known about TMAU and FMO3, so as much data is needed as possible, especially test results. Also I believe the reference ranges are set too conservative, looking at it the opposite way from someone who thinks they have a malodor problem. If someone feels they have a metabolic malodor problem and have say a few SNP's that are currently regarded as 'harmless', then personally I think the person is right.  

So I am grateful for such papers, and in this one the number deemed positive for TMAU was relatively high, but I personally feel the reference ranges are still too conservative and so many will get 'false negatives'.
       

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Update Aug 17 :
Genos is back with it's EXOME test
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Note :
Exome/Genome testing may be better option than single gene testing.

See this post : link

Note : Genos Exome Testing.

Exome testing is almost the same price now as single gene testing. Also Genos is consumer friendly, which standard DNA labs are not.

So the blog offer to test solely for FMO3 is almost obsolete, and so no longer offered.


Does Genos fully sequence FMO3 gene ?

At the moment it is not clear, but hoped this will become clear over the next few months

Note : possible 'wild west' way of testing FMO3
Use an ancestry dna site and rummage through the raw data

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