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

22 November 2016

cystathionine : malodor ? (cystathioninuria)

My Genos result showed I carry a common fault for enzyme cystathionase.
This enzyme changes cystathionine to cysteine.
Part of the 'methionine cycle'.
Currently regarded as 'harmless'.
May be worth investigating as another possible enzyme disorder that causes 'systemic body odor'.

Looking for enzyme disorders that may cause 'systemic body odor'.
Currently FMO3 is the only enzyme thought to cause 'benign' systemic/metabolic body odor. Even then, only the FMO3 substrate trimethylamine is regarded as causing malodor, whereas FMO3 oxidizes many malodorous compounds.
While FMO3 makes a good main suspect for explaining many systemic body odors, we must not rule out any possible enzymes at fault.

Cystathionine gamma-lyase enzyme (also known as cystathionine) CTH.
My Genos DNA result showed I carry a common fault in the cystathionine enzyme.
This enzyme converts cystathionine to cysteine.
I'm thinking of it as part of the 'methionine pathway, a sulfur amino acid. Perhaps it could also be known as part of the 'methylation pathway' (see disclaimer below).
The fact it's to do with sulfurs makes me wonder if it might be potential 'systemic body odor' enzyme candidate.
But maybe up to 24% carry this fault, so you have to think this works against it being a possible 'systemic body odor' candidate.
But I don't rule it out.

CTH is dependent on vitamin B6. Usually if you have a genetic fault it's not likely to respond to 'co-factor therapy', but who knows.

This disorder is known as cystathioninuria, but currently regarded 'benign' (harmless). So very little research has gone into it since noted in the 60's. Pretty much like TMAU.
Like TMAU, it's listed as not affecting 'carriers', but as we see with TMAU it's likely that some carriers are affected (probably the bulk of cases) in that they will be transient. But maybe 'carriers' with problems are likely to be 'compound carriers' (i.e. carry more than 1 fault), although I rule nothing out.
In this case I have been noted as carrying 1 CTH fault, but as with previous DNA tests I have done, I can't be sure all 'variations' in this gene have been listed by Genos, so can't be sure I only carry 1 fault.

Thoughts for now.
Currently I am low-key about this finding, but will of course investigate further as a loose lead. Perhaps it's a case of this fault compounding with my FMO3 faults to make an uncommon mix that causes overload problems (who knows).

Others CTH results.
I would be interested if other 'smellies' also carry this fault. This would make it an enzyme of more interest. It says maybe 22% carry this fault, so it would seem that this 1 fault alone does not explain smelling (as then 22% of population would smell at times). My guess is that maybe 1-3% population have 'systemic body odor' episodes (currently enzymes responsible unknown).

Biochemical test :
The biochemical/phenotype test would be testing for cystathionine in body fluids. I have seen it tested in blood. Urine would be easier. Sometimes it is added to a compilation test such as 'amino acid' test or 'methylation profile test' (such as Doctor's Data test). I would guess by mainstream heath systems, normally not much attention would be given to raised levels unless very excessive. The patient would not be notified or be given the raw data. 'New World' testers might notify of raised levels, and presumably give the raw data anyhow.
Links :
Cystathioninuria (brittanica encyclopedia)

disclaimer : Don't take anything I have wrote as fact.  

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Genos is back with it's EXOME test

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
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