Download LABORATORY DETECTION OF TRIMETHYLAMINURIA ( TMAU

Trimethylaminuria: history, diagnosis
and genetics
George Preti, PhD & Danielle R. Reed, PhD
Monell Chemical Senses Center
&
Paul V. Fennessey, PhD
Department of Pediatrics, Children’s Hospital Colorado
University of Colorado, Anschutz Medical Campus
In memory of Susan S. Tjoa, who
dedicated more than 25 years working
with patients who suffer from TMAU
Outline
1. Recognition of TMAU as disease entity and
development of choline challenge test
Dr. Fennessey
2. Evaluation of individuals with malodor
problems
Dr. Preti
3. Genetics of TMAU
Dr. Reed
Outline
1. Recognition of TMAU as disease entity and
development of choline challenge test
Dr. Fennessey
2. Evaluation of individuals with malodor problems
Dr. Preti
3. Genetics of TMAU
Dr. Reed
Public Empathy Missing for TMAU Patients
Because of the strong odor of patients with
TMA excess . . .
• Others react with feelings of repulsion and
rejection over perceived hygiene issues.
• Most TMAU patients suffer from the resulting
personal isolation and rejection.
Medical Ignorance Surrounding TMAU
Patient Diagnosis
• Most health professional training curricula
(medical, nursing, etc.) fail to include the
symptoms and causes of TMAU!
• Episodic intensity of odor often confuses the
diagnosis.
• Inheritance of TMAU is often unclear to health
providers, and genetic tests often are
inconclusive.
Medical Ignorance Surrounding TMAU
Patient Diagnosis
• Thank goodness for
– The Internet
– Patient support groups
– Other rare disease info on TV and the Web
Without these sources, many TMAU
patients would still be in the dark about
this genetic disease!
Milestones in the History of TMAU
• 1842 and 1858
– Two reports of TMAU-like disease (Lancet)
• 1970
– First clinical description: Humbert et al., in Denver (Lancet)
• 1970-1985
– Reports of isolated and sporadic cases
– Data suggest diet plays an important role in the disease
• 1980-2000
– Genetic studies of N-oxidation (FMO3) and other cofactors
• 1995 to present
– Systematic recognition of this rare genetic disease
Measurement of TMA Concentration
1980 - 1984:
Total TMA (mg/mg creatinine)
(concentration depends on diet)
1984 - present: Total TMA before and after ingestion
of choline test load
Ratio: (TMAO / TMA) x 100%
Normal TMAO > 95%
(ratio independent of diet)
Case Studies
I. Patient CD, 6.9 years of age
• Dietary choline intake decreased from 484 (baseline)
to 231 mg/d (week 4)—very close to minimum
requirement!
• Slight increase in liver function tests at choline intake
of 231 mg/d
• Asymptomatic (no odor) at choline intake of 264 mg/d
• Urine TMA concentrations reduced
• Correlation between 24-h choline intake and 24-h
urine TMA (r=0.80; p<0.01)
II. Patient TA, 67 years of age
• Reduced choline intake from 1074 to 669 mg/d but
remained symptomatic—patient lost to follow-up
TMAU: Establish Adequate Choline Intake
to Meet Dietary Reference Intakes
Life Stage Group
Adequate Choline Intake* (mg/day)
Infants
0 - 6 months
7 - 12 months
125
150
Children
1 - 3 years
4 - 8 years
200
250
Male
375
550
550
Female
375
400
425
Pregnancy (all child-bearing years)
NA
450
Lactation
NA
550
Older Children/ Adults
9 - 13 years
14 - 18 years
> 19 years
*Adequate intake is a value based on observed or experimental estimates of
intake by a group of healthy people.
Caveat: "There are few data to assess whether a dietary supply of choline is
needed at all stages of the life cycle" — Food and Nutrition Board,
National Academy of Sciences, 1998
Causes of Variability in
TMA Odor Intensity
TMA appearance after a 5 g oral choline load (adult):
0 - 8 hours
8 - 16 hours
16 - 24 hours
23%
55%
22%
(rapid passage through gut)
(slow passage through gut)
(poor passage through gut)
Speculate that gut bacteria in colon is cause of peak
production
• Supported by literature reports of TMA suppression by
antibiotics
Causes of Variability in
TMA Odor Intensity
• Estimated production of TMA from turnover of
intrinsic biomolecules:
– Micrograms (0.001 mg)
• Estimated production of TMA from action of
gut bacteria on natural products in the diet
– Milligrams (>1.0 mg)
• Difference of >1000x (depending on diet)
Summary
• Information about this disorder needs to be
taught to health care providers.
• Biochemical confirmation of TMAU is critical!
• Most patients do not have affected parents or
siblings.
Outline
1. Recognition of TMAU as disease entity and
development of choline challenge test
Dr. Fennessey
2. Evaluation of individuals with malodor
problems
Dr. Preti
3. Genetics of TMAU
Dr. Reed
Normal Human Body Odors
Mostly formed by interactions of skin gland
secretions and microorganisms:
• Scalp / hair
• Genital / vaginal
• Mouth breath
• Feet
• Axillae / underarms • Skin / hands
• Chest
Before the 20th century and widespread use
of scented soaps and consumer products, it
was more apparent that humans emit a
variety of volatile odorous metabolites.
Monell Patient Characteristics
• ~1985-1995: many referred by physician or dentist.
• Internet: many now self-referred.
• Patients mostly from the US but also from Canada,
Honduras, Venezuela, and the UK.
• Many have been to 4 clinical and/or dental
specialists.
• All patients undergo multistep exam involving both
analytical and sensory techniques.
– The critical part is a choline challenge test to
determine the diagnosis of TMAU.
Large Undiagnosed Population
of Individuals with TMAU
• Diagnosed via choline challenge test
(Tjoa and Fennessey, Anal Biochem 197:77-82, 1991).
• Trimethylamine (TMA) is a gas at body temperature and
has a strong, pungent, offensive, fishy odor.
– At low concentrations it may be perceived as
“foul” or “unpleasant.”
– Reported to be found in all body fluids.
• “Fish odor syndrome” should not be used—only ~10% of
our TMAU-positive individuals have this presentation.
• Symptoms are sporadic and may escape notice due to
low choline intake or specific anosmia in the clinician
(rare).
Trimethylaminuria Patients at
Monell Center
• >350 individuals
• 111 (~ 32%) diagnosed with some form of
TMAU (Dr. Reed will elaborate further)
• Average age of our TMAU-affected
population is 43.6 years (range, 3-79 years)
Figure 1. Presenting symptoms of TMAU-positive patients
TMAU Positive
Body
odor/oral
malodor
Genital/oral
malodor
Chronic
halitosis
Body odor
50
40
30
20
10
0
Bad
taste/oral
malodor
# Individuals
Patient Self-Reports of Symptoms:
Reasons for Seeking Help
TMAU Demographics
Proportion of sample .
• 3x more women than men are TMAU positive
• Many are African American
1.00
0.75
p<
.000001
p < .04
African American
Females
White Females
0.50
0.25
0.00
Observed
Expected
Females’ Ability to Metabolize TMA
Depends on Menstrual Cycle
p = .07
100
%
TMAO in urine
p = .41
p = .09
75
50
25
0
Nonmenses
Not
close
post/hx
±7 days of
within
7
menses
days
Menstrual cycle status
Non-TMAU-Related Complications
• Syndromes such as Prader-Willi and Noonan’s
• Skin rashes
• Seizures
• Hypertension (severe, labile, moderate)
• Psychiatric dysfunction—impaired metabolism of
N- and S-containing compounds
• Depression
• Sarcoidosis
• IBS and other lower GI problems (??)
Non-TMAU-Related Complications
• Most patients appear to lead normal lives
and work at a variety of professions
• Main problem: Psychosocial
– Caused by odor production/symptoms
– Tied to individual personality
Summary
• Our results demonstrate the need to screen for
TMAU with an objective, analytical test and not
rely upon olfactory reports.
• Only ~10% of TMAU patients have had a
fishlike or malodor during their exam.
• Patients may not be aware of when odor is
present or the intensity of their own odor.
Summary (cont.)
• Most of our referred patients have had a
similar history.
• Many do not smell badly at all (organoleptic
evaluation of breath, axillae, clothing items).
– Very few patients have high levels of odorproducing axillary bacteria (relative to “normal”) or
much axillary odor.
• Amelioration of symptoms:
– Short term: antibiotics, osmotic laxatives
– Longer term: choline and saltwater fish restriction,
OTC supplements
Summary (cont.)
• Both TMAU and non-TMAU patients may have
bad breath caused by volatile sulfur compounds
– 57% of TMAU-positive patients
– 60% of non-TMAU patients
• Female patients
– Either more affected by TMAU or present in greater
numbers to a clinic for relief of symptoms
– Many are African American
Summary (cont.)
• Decreased FMO3 efficiency due to complications
(e.g., viral infections/ drug intake)
• Funding needed for
– Follow-up
– In-depth study of symptoms vs. treatment regimes
• Etiology / genetics / other odor-producing genetic
disorders ??
Outline
1. Recognition of TMAU as disease entity and
development of choline challenge test
Dr. Fennessey
2. Evaluation of individuals with malodor problems
Dr. Preti
3. Genetics of TMAU
Dr. Reed
FMO3 and Trimethylaminuria
Choline
GUT
bacterial
action
Trimethylamine
(TMA)
TMA
LIVER
FMO3
TMA N-oxide
X FMO3
trimethylaminuria
Professor Shephard and Phillips, 2nd webcast
FMO3 Gene
R51G
N114S
A52T
P153L
E32K
M82T
M66I
I37T
V58I
K64KfsX2
N61S
G148X
V143E
T201K
I199T
R238P
R223Q
D198E
C197fsX
M405IfsX
E314X
R308Q
E305X
W388X
G475D
532
Q470X
M434I
R500X
K394KfsX11
R492W
R387L
Professor Shephard and Phillips, 2nd webcast
Trimethlyamine concentration in urine
as a quantitative trait.
Nicholson et al. 2011
Epistasis: two or more genes
that interact
Exome Sequencing
• Exome: all protein-coding regions of the
genome
• Hunt for other genetic variants
associated with TMAU
• Ongoing!
FMO3 and Trimethylaminuria
Choline
GUT
bacterial
action
Trimethylamine
(TMA)
TMA
LIVER
FMO3
TMA N-oxide
X FMO3
trimethylaminuria
Professor Shephard and Phillips, 2nd webcast
Choline Utilization (Cut) Gene Cluster
Craciun and Balskus 2012
Looking ahead:
• Proportion of gut bacteria with
Cut enzymes
• Small molecule inhibitors of
Cut enzymes
TMAU and Risk of Atherosclerosis
Bennett et al. 2013
Summary
•
FMO3 gene
•
PYROXD2 gene
•
Exome sequencing
•
Gut bacteria Cut enzymes
•
Health benefits of TMAU?