NM_001002294.3:c.198G>T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM2PP3_StrongPP5_Moderate

The NM_001002294.3(FMO3):c.198G>T(p.Met66Ile) variant causes a missense change. The variant allele was found at a frequency of 0.000018 in 1,613,742 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000019 ( 0 hom. )

Consequence

FMO3
NM_001002294.3 missense

Scores

Clinical Significance

Likely pathogenic criteria provided, single submitter P:2

Conservation

PhyloP100: 6.81

Publications

15 publications found

Variant links:

Genes affected

FMO3 (HGNC:3771): (flavin containing dimethylaniline monoxygenase 3) Flavin-containing monooxygenases (FMO) are an important class of drug-metabolizing enzymes that catalyze the NADPH-dependent oxygenation of various nitrogen-,sulfur-, and phosphorous-containing xenobiotics such as therapeutic drugs, dietary compounds, pesticides, and other foreign compounds. The human FMO gene family is composed of 5 genes and multiple pseudogenes. FMO members have distinct developmental- and tissue-specific expression patterns. The expression of this FMO3 gene, the major FMO expressed in adult liver, can vary up to 20-fold between individuals. This inter-individual variation in FMO3 expression levels is likely to have significant effects on the rate at which xenobiotics are metabolised and, therefore, is of considerable interest to the pharmaceutical industry. This transmembrane protein localizes to the endoplasmic reticulum of many tissues. Alternative splicing of this gene results in multiple transcript variants encoding different isoforms. Mutations in this gene cause the disorder trimethylaminuria (TMAu) which is characterized by the accumulation and excretion of unmetabolized trimethylamine and a distinctive body odor. In healthy individuals, trimethylamine is primarily converted to the non odorous trimethylamine N-oxide.[provided by RefSeq, Jan 2016]

FMO3 Gene-Disease associations (from GenCC):

trimethylaminuria
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
severe primary trimethylaminuria
Inheritance: AR Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae)

FMO3 links:

ENSG00000231424 (HGNC:40240):

ENSG00000231424 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.943

PP5

Variant 1-171103850-G-T is Pathogenic according to our data. Variant chr1-171103850-G-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 16306.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FMO3	NM_001002294.3 link	c.198G>T	p.Met66Ile	missense_variant	Exon 3 of 9	ENST00000367755.9	NP_001002294.1	P31513A0A024R8Z4Q53FW5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
FMO3	ENST00000367755.9 link	c.198G>T	p.Met66Ile	missense_variant	Exon 3 of 9	1	NM_001002294.3	ENSP00000356729.4		P31513
FMO3	ENST00000479749.1 link	c.198G>T	p.Met66Ile	missense_variant	Exon 3 of 6	5		ENSP00000477451.1		V9GZ60

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152140

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000796

AC:

AN:

251244

AF XY:

0.00000737

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000176

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000192

AC:

AN:

1461602

Hom.:

Cov.:

AF XY:

0.0000138

AC XY:

AN XY:

727092

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33476

American (AMR)

AF:

0.00

AC:

AN:

44688

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39682

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53408

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000198

AC:

AN:

1111816

Other (OTH)

AF:

0.0000994

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.495

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152140

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74306

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41442

American (AMR)

AF:

0.00

AC:

AN:

15250

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10614

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68028

Other (OTH)

AF:

0.00

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Trimethylaminuria

Pathogenic:2

Jan 01, 1999

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

Sep 08, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: FMO3 c.198G>T (p.Met66Ile) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251244 control chromosomes. c.198G>T has been reported at a compound heterozygous state along with an apparently pathogenic missense change of FMO3 in at-least one individual affected with Trimethylaminuria (example, Akerman_1999, Cashman_1998). These data indicate that the variant may be associated with disease. At least two publications report experimental evidence evaluating an impact on protein function. The most pronounced variant effect results in demolished kinetic parameters of FMO3 substrate oxidation, likely due to loss of incorporating/retaining the FAD cofactor (Treacy_1998, Yeung_2007). Additionally, one variant at the Met66 residue has been reported as likely associated with disease (p.Met66Val), suggesting that this codon might be functionally important (PMID: 33831674). The following publications have been ascertained in the context of this evaluation (PMID: 10479479, 9536088, 17531949). No submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.82

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.16

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.062

T;T

Eigen

Pathogenic

0.69

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.89

D;D

M_CAP

Benign

0.025

MetaRNN

Pathogenic

0.94

D;D

MetaSVM

Benign

-0.63

MutationAssessor

Uncertain

2.1

M;.

PhyloP100

6.8

PrimateAI

Uncertain

0.58

PROVEAN

Uncertain

-3.6

D;.

REVEL

Uncertain

0.54

Sift

Benign

0.030

D;.

Sift4G

Benign

0.075

T;D

Polyphen

0.93

P;.

Vest4

0.81

MutPred

0.87

Loss of disorder (P = 0.0514);Loss of disorder (P = 0.0514);

MVP

0.75

MPC

0.30

ClinPred

0.98

GERP RS

4.7

Varity_R

0.65

gMVP

0.71

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.18

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over