Trimethylaminuria: Difference between revisions

Revision as of 21:16, 9 February 2025

A metabolic disorder affecting the breakdown of trimethylamine

Diagram showing autosomal recessive inheritance.

Trimethylaminuria is a metabolic disorder in which an individual is unable to convert trimethylamine into trimethylamine N-oxide. This condition has existed for centuries but has only gained scientific recognition and support in the past 30 years.

What is Trimethylamine?

Trimethylamine is the compound responsible for the strong fish odor. In contrast, trimethylamine N-oxide is odorless.

What are the symptoms of trimethylaminuria?

In individuals with trimethylaminuria, trimethylamine accumulates in the body and is released through sweat, urine, reproductive fluids, and breath, causing a strong fishy odor. The severity of the odor varies among individuals. Despite this symptom, affected individuals are typically healthy.

The condition appears to be more common in women than in men, possibly due to the influence of sex hormones such as progesterone and estrogen. Symptoms often worsen around puberty, menstruation, after taking oral contraceptives, and around menopause.

What causes trimethylaminuria?

Trimethylaminuria results from an impaired version of the enzyme flavin-containing monooxygenase 3 (FMO3), which converts trimethylamine into trimethylamine N-oxide. The FMO3 gene codes for this enzyme. Mutations in the FMO3 gene are linked to the condition, although the full range of the enzyme’s functions remains unknown.

Is trimethylaminuria inherited?

Yes, trimethylaminuria is inherited in an autosomal recessive pattern, requiring two non-functioning copies of the FMO3 gene for symptoms to appear. Carriers, who have only one altered gene, typically do not exhibit symptoms, though some may experience mild, temporary episodes of fish-like odor. Genetic mutations, stress, and diet may influence the severity and onset of symptoms.

How is trimethylaminuria diagnosed?

A urine test is used to diagnose trimethylaminuria by measuring the levels of trimethylamine and trimethylamine N-oxide. The TMA challenge test involves administering trimethylamine and analyzing its excretion levels. Genetic testing can also identify mutations in the FMO3 gene.

How is trimethylaminuria treated?

There is no cure for trimethylaminuria, but individuals can manage symptoms through:

Avoiding foods high in trimethylamine and its precursors, such as:

 * Milk from wheat-fed cows
 * Eggs
 * Liver
 * Kidney
 * Peas
 * Beans
 * Peanuts
 * Soy products
 * Brassicas (e.g., Brussels sprouts, broccoli, cabbage, cauliflower)
 * Lecithin and fish oil supplements
 * Seafood (e.g., fish, cephalopods, crustaceans)

Taking low-dose antibiotics to reduce gut bacteria that produce trimethylamine.
Using laxatives to decrease intestinal transit time and limit trimethylamine production.
Taking supplements such as:

 * Activated charcoal (750 mg twice daily for ten days)
 * Copper chlorophyllin (60 mg three times per day after meals for three weeks)
 * Riboflavin (30-40 mg, 3-5 times daily with food) to enhance residual FMO3 enzyme activity.

Using moderate pH soaps (pH 5.5-6.5) to retain trimethylamine in a less volatile form for removal by washing.
Avoiding factors that promote sweating (e.g., exercise, stress, and emotional distress).

Enzyme replacement therapy with FMO3 enzyme is not currently an option.

What laboratories offer testing for trimethylaminuria?

The following laboratories offer diagnostic testing for trimethylaminuria:

Children's Hospital Colorado Biochemical Genetics Lab

 * Phone: 720-777-6711
 * Contact: Lab Client Services
 * Email: [[1]]

Monell Chemical Senses Center, University of Pennsylvania

 * Phone: 215-898-4713
 * Contact: George Preti, Ph.D.
 * Email: [[2]]
 * Note: This laboratory may have a long waiting list.

Clinical Research on Trimethylaminuria

Currently, the National Human Genome Research Institute (NHGRI) is not conducting studies on trimethylaminuria.

For research opportunities:

ClinicalTrials.gov
NHGRI Clinical Studies
Clinical Research FAQs

Additional Resources for Trimethylaminuria

Related Pages

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@@ Line 1: / Line 1: @@
 {{Short description|A metabolic disorder affecting the breakdown of trimethylamine}}
-{{Use dmy dates|date=October 2023}}
+[[File:Autorecessive.svg|thumb|right|Diagram showing autosomal recessive inheritance.]]
+[[File:Trimethylamine_chemical_structure.png|thumb|right|Chemical structure of trimethylamine.]]
+'''Trimethylaminuria''' is a [[metabolic disorder]] in which an individual is unable to convert [[trimethylamine]] into [[trimethylamine N-oxide]]. This condition has existed for centuries but has only gained scientific recognition and support in the past 30 years.
+== What is Trimethylamine? ==
+[[Trimethylamine]] is the compound responsible for the strong [[fish odor]]. In contrast, [[trimethylamine N-oxide]] is odorless.
-'''Trimethylaminuria''' (TMAU), also known as '''fish odor syndrome''', is a rare metabolic disorder characterized by the body's inability to break down [[trimethylamine]], a compound with a strong odor often described as similar to that of rotting fish. This condition can lead to a significant social and psychological impact on affected individuals.
+== What are the symptoms of trimethylaminuria? ==
+In individuals with trimethylaminuria, trimethylamine accumulates in the body and is released through [[sweat]], [[urine]], [[reproductive fluids]], and [[breath]], causing a strong [[fishy odor]]. The severity of the odor varies among individuals. Despite this symptom, affected individuals are typically [[healthy]].
-==Signs and symptoms==
+The condition appears to be more common in [[women]] than in [[men]], possibly due to the influence of [[sex hormones]] such as [[progesterone]] and [[estrogen]]. Symptoms often worsen around [[puberty]], [[menstruation]], after taking [[oral contraceptives]], and around [[menopause]].
-The primary symptom of trimethylaminuria is a strong body odor resembling that of fish. This odor can emanate from the breath, sweat, urine, and reproductive fluids. The intensity of the odor can vary over time and may be influenced by factors such as diet, hormonal changes, and stress.
-==Causes==
+== What causes trimethylaminuria? ==
-Trimethylaminuria is caused by mutations in the [[FMO3]] gene, which provides instructions for making an enzyme that breaks down trimethylamine. When this enzyme is deficient or absent, trimethylamine accumulates in the body and is released in bodily fluids, leading to the characteristic odor.
+Trimethylaminuria results from an impaired version of the enzyme [[flavin-containing monooxygenase 3]] (FMO3), which converts [[trimethylamine]] into [[trimethylamine N-oxide]]. The [[FMO3 gene]] codes for this enzyme. Mutations in the FMO3 gene are linked to the condition, although the full range of the enzyme’s functions remains unknown.
-===Genetics===
+== Is trimethylaminuria inherited? ==
-Trimethylaminuria is inherited in an [[autosomal recessive]] pattern, meaning that both copies of the gene in each cell have mutations. Parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
+Yes, trimethylaminuria is inherited in an [[autosomal recessive]] pattern, requiring two non-functioning copies of the [[FMO3 gene]] for symptoms to appear. Carriers, who have only one altered gene, typically do not exhibit symptoms, though some may experience mild, temporary episodes of fish-like odor. Genetic mutations, [[stress]], and [[diet]] may influence the severity and onset of symptoms.
-[[File:Autorecessive.svg|thumb|right|Diagram showing autosomal recessive inheritance.]]
+== How is trimethylaminuria diagnosed? ==
+A [[urine test]] is used to diagnose trimethylaminuria by measuring the levels of [[trimethylamine]] and [[trimethylamine N-oxide]]. The [[TMA challenge test]] involves administering trimethylamine and analyzing its excretion levels. [[Genetic testing]] can also identify mutations in the [[FMO3 gene]].
+== How is trimethylaminuria treated? ==
+There is no cure for trimethylaminuria, but individuals can manage symptoms through:
+* Avoiding foods high in [[trimethylamine]] and its precursors, such as:
+  * [[Milk]] from wheat-fed cows
+  * [[Eggs]]
+  * [[Liver]]
+  * [[Kidney]]
+  * [[Peas]]
+  * [[Beans]]
+  * [[Peanuts]]
+  * [[Soy products]]
+  * [[Brassicas]] (e.g., [[Brussels sprouts]], [[broccoli]], [[cabbage]], [[cauliflower]])
+  * [[Lecithin]] and [[fish oil supplements]]
+  * [[Seafood]] (e.g., [[fish]], [[cephalopods]], [[crustaceans]])
+* Taking low-dose [[antibiotics]] to reduce gut bacteria that produce trimethylamine.
+* Using [[laxatives]] to decrease intestinal transit time and limit trimethylamine production.
+* Taking supplements such as:
+  * [[Activated charcoal]] (750 mg twice daily for ten days)
+  * [[Copper chlorophyllin]] (60 mg three times per day after meals for three weeks)
+  * [[Riboflavin]] (30-40 mg, 3-5 times daily with food) to enhance residual [[FMO3 enzyme]] activity.
+* Using [[moderate pH soaps]] (pH 5.5-6.5) to retain trimethylamine in a less volatile form for removal by washing.
+* Avoiding factors that promote [[sweating]] (e.g., [[exercise]], [[stress]], and emotional distress).
+Enzyme replacement therapy with [[FMO3 enzyme]] is not currently an option.
+== What laboratories offer testing for trimethylaminuria? ==
+The following laboratories offer diagnostic testing for trimethylaminuria:
+* '''Children's Hospital Colorado Biochemical Genetics Lab'''
+  * Phone: 720-777-6711
+  * Contact: Lab Client Services
+  * Email: [[Mailto:LabClientServices@childrenscolorado.org|LabClientServices@childrenscolorado.org]]
+* '''Monell Chemical Senses Center, University of Pennsylvania'''
+  * Phone: 215-898-4713
+  * Contact: [[George Preti]], Ph.D.
+  * Email: [[Mailto:preti@monell.org|preti@monell.org]]
+  * Note: This laboratory may have a long waiting list.
-==Diagnosis==
+== Clinical Research on Trimethylaminuria ==
-Diagnosis of trimethylaminuria is based on clinical evaluation and the detection of elevated levels of trimethylamine in the urine. Genetic testing can confirm mutations in the FMO3 gene.
+Currently, the [[National Human Genome Research Institute]] (NHGRI) is not conducting studies on trimethylaminuria.
-==Management==
+For research opportunities:
-There is no cure for trimethylaminuria, but symptoms can be managed through dietary modifications, such as reducing the intake of foods high in trimethylamine precursors, including certain fish, eggs, and legumes. Other management strategies include the use of activated charcoal or copper chlorophyllin supplements, which may help reduce odor.
+* [[ClinicalTrials.gov]]
+* NHGRI Clinical Studies
+* Clinical Research FAQs
-==Epidemiology==
+== Additional Resources for Trimethylaminuria ==
-Trimethylaminuria is considered a rare disorder, with its prevalence not well established. It is thought to be underdiagnosed due to the social stigma associated with the condition.
+* [[Genetics Home Reference: Trimethylaminuria]]
+* [[Online Mendelian Inheritance in Man (OMIM)]]
+* [[Effects of dietary supplements on urinary excretion of trimethylamine]]
+* [[Trimethylaminuria information from the Genetics and Rare Diseases Information Center]]
+* [[Finding Reliable Health Information Online]]
-==Related pages==
+== Related Pages ==
 * [[Metabolic disorder]]
 * [[Genetic disorder]]
 * [[Body odor]]
-==References==
-{{Reflist}}
-[[File:Trimethylamine_chemical_structure.png|thumb|right|Chemical structure of trimethylamine.]]
 [[Category:Metabolic disorders]]
 [[Category:Rare diseases]]
+{{genetics}}
+{{stub}}