FMO3 paper July 2009 : Expression and characterization of functional dog flavin-containing monooxygenase 3

At the moment, FMO3 enzyme is a main suspect in most cases of 'genetic metabolic' body odor, although trimethylaminuria is the only documented form of metabolic body odor associated with this enzyme. So any research into FMO3 is of interest. especially since it is probably the most neglected and least-researched of the xenobiotic metabolizing enzymes, despite being very abundant in the liver and one of the most used, dealing with 1,000s of substrates.

Being one of the drug-metabolizing enzymes, it makes it the more surprising that little is known about FMO3, since it means those with suboptimal FMO3 function may be expected to react badly to drugs that use FMO3 for activation/detoxication.

Presumably this is why some Pfizer researchers have published this paper, being interested in the 'pharmacokinetics' of FMO3. They were investigating whether beagle FMO3 function closely co-related with human FMO3 function, since normally animals are tested upon, before human trials of new drugs. It looks as if dog FMO3 has substantial differences to human FMO3.

Pubmed abstract: http://www.ncbi.nlm.nih.gov/pubmed/19635782

Full article: http://dmd.aspetjournals.org/cgi/reprint/dmd.109.027714v1

Below are some quotes that may be of interest to metabolic body odor sufferers:

Introduction
The flavin-containing monooxygenases (FMOs) are a family of enzymes capable of catalyzing the oxidation of various drugs, xenobiotics and endogenous substrates containing a soft nucleophile, usually nitrogen or sulfur (Cashman, 2000; Krueger and Williams, 2005). In humans, FMO-dependent drug metabolism can have important clinical implications (Cashman, 2000). Like cytochrome P450s, the FMOs are microsomal enzymes that require NADPH and O2, and FMOs have shown overlapping substrate specificity with P450s. FMOs also typically convert their xenobiotic substrates into more polar products that are less pharmacologically-active and more easily excreted, thereby enhancing their elimination from the body (Cashman, 1995). The mammalian FMO gene family includes five different isoforms (FMO1 through FMO5) (Lawton et al., 1994). In humans, as well as in a variety of preclinical species, tissue distribution patterns of FMO isoforms have been described (Cashman and Zhang, 2006; Phillips and Shephard, 2008). FMO3 is the most abundantly expressed isoform in adult human liver, existing at levels similar to the major human liver P450 isoform, CYP3A4 (Haining et al., 1997). FMO3 has been observed to contribute to the metabolic clearance of a variety of drugs, e.g. cimetidine, nicotine, and tamoxifen, as
well as the diet-derived substrate trimethylamine (Cashman et al., 1992; Cashman et al., 1993; Mani et al., 1993). It has been demonstrated that FMO3 is essential for the N-oxygenation and metabolic clearance of trimethylamine (Dolphin et al., 1997; Lang et al., 1998). This led to the discovery that human FMO3 is also a highly polymorphic gene (Koukouritaki et al., 2005). Specifically, a total of 29 allelic variants of FMO3 have each been observed to be associated with the human condition known as trimethylaminuria or “fish odor syndrome” (Phillips and Shephard, 2008).

Preclinical species, e.g. mouse, rat, dog, monkey, serve as a valuable tool for the drug discovery and drug development process. Data obtained from in vivo metabolism and toxicology studies in these models are essential for scaling and prediction of pharmacokinetic and pharmacodynamic behavior of drug candidates to be potentially administered to humans. Importantly, the accuracy of such predictions greatly depends on similarity of metabolic processes between species. This makes it particularly important to have a complete characterization of the metabolic pathways of a candidate compound in a given species prior to determination of safe doses for humans. The dog is the most widely used nonrodent species in preclinical drug safety studies (Gad and Gad, 2003). We suggest that to gain a definitive understanding of the relevance of drug metabolism in dogs to that in humans, a characterization of species differences in FMOs is necessary

In summary, our study has demonstrated that dFMO3 is expressed at appreciable levels in beagle dog liver as well as in lung. Given that FMO3 is the major form expressed in human liver, expressed dog FMO3 could be an important preclinical tool when it comes to comparing pathways of hepatic drug metabolism. Our data demonstrates that dFMO3 is capable of catalyzing the N- and S-oxidation of prototypical FMO substrates. Importantly, given that the kinetic data for dFMO3 displayed some significant differences when compared with hFMO3, additional characterization of the enzyme will be necessary in order to properly interpret data from preclinical experiments where FMO3 appears to have a role. While there is considerable information on species differences in tissue distribution and expression profiles of FMOs, there is relatively little information describing metabolism of specific FMO substrates (or substrates with specific structural features) across all species. Conversely, studies that compare not just enzyme activity but also the effect of structural properties on kinetic parameters may provide greater insight and appreciation for the catalytic function of the dog FMO3 isoform and other FMO3 orthologs.

Lobbying politicians about body odor and halitosis

As time goes by, it makes sense for the body odor and halitosis community to lobby politicians to do something about the said conditions. Especially since in most cases, it has nothing to do with hygiene, and sufferers are very clean and 'unwilling' sufferers. It is in most cases probably a medical condition. Probably the community will learn how to best organise themselves over the years, but perhaps a starting point is to write to President Obama using his contact form.

The next part of the plan is what exactly to write ? Again this will likely develop naturally as time goes by, but for now the blog has written the President informing him of the large number of sufferers of what is likely metabolic body odor, and asked him to instruct the NIH to set up a Body Odor and halitosis research center and clinic since this would be a very efficient way of dealing with the issue. It was also pointed out a smell & disorder clinic had been set up by the NIH many years ago, to what many may feel has a far far lower 'suicide/dismissal/unemployment rate' than body odor or halitosis.

Obviously we expect the letter to have no impact but you never know. Hopefully it will also stimulate ideas as to how to influence politicians, and what our aims are. Perhaps someday all politicians will be aware of metabolic body odor and halitosis, like any other medical condition.

you can write President Obama here : http://www.whitehouse.gov/CONTACT/
Write to your senator : http://www.senate.gov/general/contact_information/senators_cfm.cfm
Contact the NIH advisory commitee : http://acd.od.nih.gov/Contact.asp

Maudlinrefletions.wordpress.com

A young person has started a blog about their situation as they test for TMAU. You can follow their blog here: http://maudlinreflections.wordpress.com/

Dimethylglycine dehydrogenase enzyme (DMGDH)

dmgdhd is a disorder characterized by fish odor, muscle fatigue with increased serum creatine kinase.

Pathway: choline metabolismTrimethylaminuria is the only real 'accepted' form of metabolic body odor by those few in the medical system who are aware of any form, but another often forgotten about is dimethylglycinuria, to do with saturation of the Dimethylglycine dehydrogenase enzyme. However there seems to be only one recorded case of DMGU, and it's unclear if this is because no-one tests for it or it is so rare.
(2001 dimethylglycinuria case)

There are a lot of similarities with 'official' TMAU, in that it is thought to give off a fish smell. Also the enzyme is part of the choline metabolism. That said, presumably this enzyme deals only with one 'substrate' (it oxidizes dimethylglycine), whereas FMO3 oxidizes 1,000s of substrates (including trimethylamine). The sufferer was also said to have a high creatine kinase blood level, which may be a clue as to this problem (or maybe not). Whilst FMO3 uses riboflavin as a co-factor, DMGDH uses folate as it's co-factor.

It would be interesting to know if they discovered DMGu by using an open-ended look for volatile organic compounds in a mass spectrometer/gas chromatography test, or if they were only looking for DMG. The former would be the best starting test for defining a metabolic body odor problem, since in most cases we don't know what we are looking for yet.

Why only one case has been recorded is not known, however it would seem at the moment that an assumption could be made that DMGu is very rare and that one or more other forms of metabolic body odor are far more common.

Dimethylglycine dehydrogenase is a gene that encodes an enzyme involved in the catabolism of choline, catalyzing the oxidative demethylation of dimethylglycine to form sarcosine. The enzyme is found as a monomer in the mitochondrial matrix, and uses flavin adenine dinucleotide and folate as cofactors. Mutation in this gene causes dimethylglycine dehydrogenase deficiency, characterized by a fishlike body odor, chronic muscle fatigue, and elevated levels of the muscle form of creatine kinase in serum.

...defects in dmgdh are the cause of dmgdh deficiency (dmgdhd) [mim:605850]. dmgdhd is a disorder characterized by fish odor, muscle fatigue with increased serum creatine kinase. biochemically it is characterized by an increase of n,n- dimethylglycine (dmg) in serum and urine.

http://harvester.embl.de/harvester/Q9UI/Q9UI17.htm

Biochemically it is characterized by an increase of N,N-dimethylglycine (DMG) in serum and urine.

Pathway: Amine and polyamine degradation; betaine degradation; sarcosine from betaine...

SwissProt Accession No.: Q9UI17 Dimethylglycine dehydrogenase, mitochondrial precursor; (Homo sapiens); 99% similarity over 866 a.a.

(Last modified July 7, 2009. Version 80.)

http://www.uniprot.org/uniprot/Q9UI17&format=html

Article in March 2005 Orthodontic Cyberjournal about halitosis

Some extracts from an article in the Orthodontic Cyberjournal dated March 2005

Evaluation of expired air:

According to Delanghe et al.,87% of malodor originates from the mouth(9). The simplest way to distinguish oral from non-oral sources of maloder is to compare the smell coming from the mouth with that exiting the nose(5). Any potential nasal source of malodor is differentially diagnosed by directing the subject to seal the mouth and exhale only through the nose. A potential oral source of malodor is detected by directing the patient to pinch the nose closed and exhale through the mouth(10).

Pungent odor from the expired air can indicate lesions or disease of the nasopharynx, nose or sinuses. The nasopharynx is a common site of bacterial colonization contributing to bad breath. Any condition that alters the mucous membrane of the nose including atrophic rhinitis or rhinitis medicametosa can contribute to bacterial overgrowth and malodor. Chronic sinusitis, unilateral choanal atresia and nasal foreign bodies also cause halitosis(10).

If the same malodour is detected from both nasally and orally expired air, a systemic or respiratory tract source should be suspected(10). Malodor can be an early symptom of nasal tumors. Referral to an otolaryngologist is indicated if infection, foreign body or neoplasm of these structures is suspected.

A more noxious odour found in the orally expired air than air expired nasally can indicate an oral, oropharyngeal, hypopharyngeal or, rarely, a gastric source (10).

The results of a study by Tonzetich, Peti and Huggins (1978) provided a satisfactory explanation of this phenomenon when they reported finding distinct variations of hydrogen sulfide, methyl mercaptan and dimethyl sulfide in mouth air during different stages of the menstrual cycle.Menstruation:

It has been reported that during menstruation or certain menstrual cycles(Massler, Emslie and Bolden, 1951), some women have bad breath. This is most likely secondary to hormonal changes. The results of a study by Tonzetich, Peti and Huggins (1978) provided a satisfactory explanation of this phenomenon when they reported finding distinct variations of hydrogen sulfide, methyl mercaptan and dimethyl sulfide in mouth air during different stages of the menstrual cycle.

Pathologic causes of halitosis
Non-oral(Systemic) causes of halitosis:

Odors can be derived from the mouth, the lungs, and the nasal passages. Any putrefaction in the lungs or in the nasal passages would also give off odiferous substances during the flow of air in the process of breathing...

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Full article:
http://www.oc-j.com/mar05/Halitosis-Part_1.htm

Mystery diagnosis episode about Trimethylaminuria featuring Cheryl Marshall and Dr Paul Fennessey

Someone has kindly uploaded the recent Mystery Diagnosis case about trimethylaminuria featuring Cheryl Marshall, who founded the NORD Trimethylaminuria Fund. It cannot be understated how grateful we are to Cheryl for bravely appearing on national TV, and for the person who uploaded it to youtube for enabling worldwide viewing of the episode. Thank you both very much.

Cheryl Marshalls fundraising site for the NORD TMAU Fund
About the NORD Trimethylaminuria Fund :

NORD (National Organization for Rare Disorders, Inc.) is a U.S. national charity that was formed in 1983 by the individuals and organizations who supported the Orphan Drug Act, an important piece of legislation that provides incentives to encourage the development of new treatments for rare disorders. A TMAU sufferer, Cheryl Marshall, set up the TMAU fund. The purpose of the fund is to collect donations that will be used solely towards research into TMAU. When the balance of the fund reaches $35,000 tax deductible contributions, the process of issuing a Request for Research Proposals from research scientists or investigators in the field of TMAU can begin; thus triggering further funding from NIH to set in motion an 'official' research. It is possible to donate online.

NORD provides accurate, reliable information and is a strong voice in advocating for needed research and improved treatments. Every month NORD provides a running list of the funds along with the total amount donated in their UPDATE newsletter.

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related links:
see all youtube videos uploaded by Lillyput2

TMAU.org.uk doing an interview with Dr Robin Lachmann

TMAU.org.uk will be conducting an interview with Dr Robin Lachmann and are inviting readers to send in questions for him via their forum.

Dr. Lachmann, Consultant in Metabolic Medicine, has kindly agreed to answer a list of FAQs. I will create a new catergory in the forums so that you can submit any FAQs you may have. Dr. Lachmann is an expert in TMAU and his input will be invaluable

Dr Robin Lachmann is a Consultant at the Charles Dent Metabolic Unit in London Patients in London and the South of England diagnosed with TMAU are often referred to Dr Lachmann since he has some background in TMAU (Charles Dent metabolic unit is an Adult Metabolism Unit). He was the Dr who Rachel went to visit in the BBC documentary about TMAU.

We have previously posted an interview with Dr Lachmann, which was well-received by the community. Thank you to tmau.org.uk and Dr Lachmann for giving everyone an opportunity to ask questions again. Co-operation with experts is always welcome.

Launching MeBO Research

It is with great enthusiasm that I launch our new non-profit organization with the aim to promote research for all types of body odor. Much hard work on my part as well as on the part of many others in this international community has been put forth to bring this opportunity about. This is the opportunity for us sufferers to take the yet-to-be-discovered solutions of our condition into our own hands by creating a testing and research culture ourselves, since the scientific/medical systems will not do it for us.This is the opportunity for us sufferers to take the yet-to-be-discovered solutions of our condition into our own hands by creating a testing and research culture ourselves, since the scientific/medical systems will not do it for us..


You're invited to visit our MeBO Research's website at meboresearch.com where our Mission, Strategies, Short-term goals, and Long-term goals are explained. Also, please visit our interactive 'Have your say' page, and tell us your story. Tell us what you think of the information written on this website, and tell us in which way you would like to participate in helping MeBO grow into a large international organization that seeks results not only for our future but also for the here and now.


Please note that this is only the Beta Phase of the website, and would appreciate you notifying us of any bugs or other corrections that need to be made....tell us in which way you would like to participate in helping MeBO grow into a large international organization that seeks results not only for our future but also for the here and now.

We hope you enjoy it; and we look forward to a strong, enthusiastic, and spirited community participation in all aspects of this effort so that it may indeed be successful in order for each and every one of us to be able to someday walk out of our homes into the world confident that our odor will not interfere with our lives...

María

The alternative is to maintain the status quo, i.e., waiting for the scientific / medical system to come up with significant funding and research for us on its own initiative, which is a very unrealistic possibility.
www.meboresearch.com

Halitosis research : 32% suffer from halitosis in Swiss study

Prevalence of halitosis in the population of the city of Bern, Switzerland: a study comparing self-reported and clinical data.
Bornstein MM, Kislig K, Hoti BB, Seemann R, Lussi A.

Department of Oral Surgery and Stomatology, School of Dental Medicine, University of Bern, Bern. Switzerland. michael.bornstein@zmk.unibe.ch

Epidemiological data on halitosis are rare. In this study we evaluated the prevalence of halitosis in the population of the city of Bern, Switzerland, using a standardized questionnaire and clinical examination. First of all, a standardized questionnaire was filled out by all 419 participants. In the clinical examination, 'objective' values for halitosis were gathered through two different organoleptic assessments and by the measurement of volatile sulfur compounds (VSC). Additionally, tongue coating and the modified periodontal screening index (PSI) were evaluated for each participant. The questionnaire revealed that 32% of all subjects sometimes or often experienced halitosis. The organoleptic evaluation (grade 0-5) identified 48 persons with grade 3 and higher. Measurement of VSC identified 117 subjects (28%) with readings of >or= 75 parts per billion (ppb). Tongue coating, modified PSI, and smoking were significantly associated with higher organoleptic scores, and tongue coating and smoking were associated with higher VSC values. For about one-third of the Bernese city population, halitosis seems to pose an oral health problem. Only a weak correlation between self-reported halitosis and either organoleptic or VSC measurements could be detected.

http://www.ncbi.nlm.nih.gov/pubmed/19583753

Notes:
Sadly the paper likely does not take into account the possibility of metabolic/alveolar halitosis, since this is not known about by most in halitosis research. Metabolic halitosis seems to be almost always transient and it is not known how to exactly provoke it (apart from choline for TMAU).

New FMO3 paper : Norwegian family with novel FMO3 mutation

Another FMO3 paper was published on pubmed this week. This one involves Drs. Phillips and Shephard of London, who have a long history in FMO3/TMAU research. The paper is an observation of a Norwegian Family carrying an FMO3 mutant (a new one). Sadly this type of anecdotal paper makes up the bulk of FMO3/TMAU research. Especially recently; as opposed to big trials making breakthroughs.

The paper also shows the gap between researchers and sufferers, since the girl seems to have presented with a body odor problem, but since she doesn't fit the strict definition of TMAU by DNA (i.e. autosomal recessive) they are predicting her as a 'childhood' case. We will only be able to see if this is the case in 10 years or so.

She seems to have one copy of a 'new' severe mutation, which her mother also had a copy of. Her father seemed to have 2 other variant copies of FMO3, but she hadn't received either of them (?)

It again highlights the gray area of defining TMAU. At the moment researchers will try to shoehorn the definition into their own strict rules. Meanwhile the patient either has a transient smell problem or not. If they do have a smell problem, then the patient is the correct definition and the rules need changed (in this case we need to wait and see).

In the end, they at least found yet another 'novel' mutant to add to the list of mutants. How many more of these mutants will be found is unknown, but most of these anecdotal papers seem to be new mutants nowadays.

A novel mutation in the flavin-containing monooxygenase 3 gene (FMO3) of a Norwegian family causes trimethylaminuria


Allerston CK, Vetti HH, Houge G, Phillips IR, Shephard EA.

Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK.

Loss-of-function mutations in the flavin-containing monooxygenase 3 gene (FMO3) cause the inherited disorder trimethylaminuria (TMAuria), or fish-odour syndrome. Here we describe the identification in a family from northern Norway of a novel causative mutation of TMAuria. A female child within the family presented with a TMAuria-like phenotype. The child and her mother were found to be heterozygous for a novel mutation (R238Q) in exon 6 of FMO3. The child's father lacked this mutation, but was heterozygous for a double polymorphic variant, E158K/E308G, which was not present in the child. During a consultation with her doctor the mother mentioned an uncle whom she remembered as having a strong body odour. This discussion led to genetic counselling of the uncle and analysis of his DNA showed him to be homozygous for the R238Q mutation. Analysis of the mutant FMO3 expressed in bacteria revealed that the R238Q mutation abolished catalytic activity of the enzyme and is thus a causative mutation for TMAuria. The specificity constant (k(cat)/K(M)) of the K158/G308 variant was 43% of that of ancestral FMO3. Because the child is heterozygous for the R238Q mutation and no other mutation known to cause TMAuria was detected in her DNA she is predicted to suffer from transient childhood TMAuria, whereas her great-uncle has primary TMAuria.

http://www.ncbi.nlm.nih.gov/pubmed/19577495

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related links:
NIH GeneReviews page on trimethylaminuria
Pubmed search : Shephard EA
Professor EA Shephard UCL page
Pubmed search : Phillips IR

Latest FMO3 research paper : Japanese FMO3 Inter-individual variation

This is the latest FMO research paper published on pubmed, from a group of Japanese researchers at Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Tokyo, Japan. There doesn't seem to be any significant finding, other than Japanese livers seem to vary for FMO3 as much as Caucasians ? The researchers probably reearched under the perspective of FMO3 being a 'drug metabolizing enzyme', and it is likely a small % of their work. They seem to be drug metabolism researchers (pharmacokinetics) and so will FMO3 is likely a low priority to them.

FMO3 enzyme is regarded as the enzyme saturated in the case of trimethylaminuria. It is part of the group of 'xenobiotic metabolizing enzymes' which are also the main 'drug metabolizing enzymes', although FMO is still largely perceived as unimportant by medical researchers (in comparison to the other enzymes in the group). There have been around a dozen pubmed entries on FMO3 this year

Inter-individual variation in flavin-containing monooxygenase 3 in livers from Japanese: correlation with hepatic transcription factors.

Nagashima S, Shimizu M, Yano H, Murayama N, Kumai T, Kobayashi S, Guengerich FP, Yamazaki H.

Laboratory of Drug Metabolism and Pharmacokinetics, Showa Pharmaceutical University, Tokyo, Japan.

Human flavin-containing monooxygenase 3 (FMO3)-mediated microsomal oxygenation activity, levels of FMO3 protein and FMO3 mRNA and modifications were investigated in Japanese livers genotyped for the FMO3 gene. Significant correlations were observed for benzydamine N-oxygenation or methyl p-tolyl sulfide S-oxygenation activity (in the range of approximately 20- to approximately 40-fold) and FMO3 levels determined immunochemically in liver microsomes (r(2)=0.73-0.75, p less than 0.0001, n="16)." p="0.0010," n="16)," p="0.0017," n="37)."

pubmed abstract

The full paper in PDF format can be downloaded on this page :
Inter-individual variation in flavin-containing monooxygenase 3 in livers from Japanese

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related links:
more about FMO3 on NIH page