Admin Control Panel

New Post | Settings | Change Layout | Edit HTML | Edit posts | Sign Out
March20 podcast Dr Hazen
anti-TMA pill in a year or 2 ? (scroll 12 mins)

Additional info:
MEBO Karen
at UK Findacure conf 2020

Scroll down and select country

MEBO Map Testing & Meetups

Full details :
want listed ? contact

MEBO - UBIOME study 2018



MEBO Gut Microbiome Study
"Microbial Basis of Systemic Malodor and PATM Conditions (PATM)"
Funded by uBiome Research Grant

"Microbial Basis of Systemic Malodor and PATM Conditions (PATM)"

Dynamics of the Gut Microbiota in
Idiopathic Malodor Production

Started May 2018 - Ongoing

Current people sent kits : 100/100
3 kits per person


Participation info : LINK English

MEBO Private Facebook Group
to join : go to
or contact
Join/Watch the weekly
BO Sufferers Podcasts



TMAU Petition world
TMAU UK end total:262
TMAU UK ends 23/01/20
TMAU Petition USA end total 204
USA : Moveon open
TMAU (Dominican)
Metabolomic Profiling Study

Start : Aug 2016
Stage 1 : 27 Canadian volunteers to test
Latest click here (26 oct) :
17 samples returned

Note : Stage 1 is Canada only.
Return cut-off date : passed
Analysis can take 6/8 weeks
Analysis start in/before Nov
MEBO Research is a
NORD Member Organization
See RareConnect

Popular Posts (last 30 days)

Upcoming get-togethers

Let us know if you want a meetup listed

Subscribe to Blog

Enter your email address:

Delivered by FeedBurner

You will be sent a verification email

Subscribe in a reader

Blog Archive

MEBO Research Clinical Trials

Click here to read details of the MEBO Clinical Trials
NCT03582826 - Ongoing not recruiting
Microbial Basis of Systemic Malodor and PATM Conditions (PATM)
United States 2018 - ongoing

NCT02683876 - Completed
Exploratory Study of Relationships Between Malodor and Urine Metabolomics
Canada and United States 2016 - ongoing

NCT03451994 - Completed
Exploratory Study of Volatile Organic Compounds in Alveolar Breath
United Kingdom and United States 2013 - ongoing

NCT02692495 - Completed
Evaluation of Potential Screening Tools for Metabolic Body Odor and Halitosis
United Kingdom 2009 - 2012

Sunday, May 15, 2011

FMO3 Genetics class : part 1

It is hoped readers may be interested in a series of posts about the technical side of Trimethylaminuria (TMAU), especially genetic TMAU. Genetic TMAU is deemed to be caused by a deficiency (of some degree) of the flavin mono-oxygenase Isoform 3 enzyme (FMO3). It seems the deficiency can be generally constant or can be only at certain times, such as menstruation, depending on the variant causing it.

A simplistic way to think of the genetic building of FMO3 is to think of the FMO3 protein being made up from a series of 532 amino acids in a particular sequence. An analogy to use would be a ladder with 532 rungs. If at any rung (codon) there is a fault (variant), it can cause problems depending on the expected severity of the variant. Also, a nonsense mutation is where the building of the rungs is stopped completely at a certain rung, leaving an unfinished 'ladder' to be turned into the FMO3 protein.

At each rung in the ladder, the person can potentially have a variant on one side (heterozygous) or both sides (homozygous), or be completely normal.

A common 'variant' in humans is known as E158K. It is estimated that perhaps 50% of the population are at least heterozygous for this variant. It means at rung (codon) 158, the amino acid should be glutamic acid (E), but instead is lysine (K). On it's own, this is such a small error that no negative effect on FMO3 function is expected even if the person has variant E158K on both sides (homozygous) of rung 158.

Another common variant is E308G. Using the ladder analogy again, this is a common variant at 'rung' 308. It is meant to be lysine (E), but instead is glycine (G). Again, whether the person has one copy (heterozygous) or 2 (homozygous), it is such a minor fault that normal function is predicted.

However, it now seems expected that if someone is at least heterozygous for both the above variants on the same side, i.e., on the same chromosome, from the same parent, there is predicted to be a loss of function to some degree, e.g., 80% TMA to TMAO conversion, rather than over 95%. Possibly this combination may make up most cases of genetic TMAU - they would likely be 'mild' genetic TMAU cases.

The table of symbols for amino acids
Table of human FMO3 allelic variants (to be updated soon)

E158K estimates (at least one copy) in USA population :
Caucasian 40%
African-American 40%
Hispanic 33%
Asian 14%

E308G estimates (at least one copy) in USA population :
Caucasian 19%
African American 5%
Hispanic 9%
Asian 16%

2.5% of Caucasians are estimated to have one copy of both E158K and E308G (known as a haplotype), but as long as they are not on the same chromosome then no loss of function is currently predicted.


Post a Comment