chr1-171114339-G-T

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM2PM5PP3_StrongPP5

The NM_001002294.3(FMO3):c.1160G>T(p.Arg387Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,460,998 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R387H) has been classified as Likely pathogenic.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

FMO3
NM_001002294.3 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2U:1

Conservation

PhyloP100: 7.52

Publications

13 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 9 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr1-171114339-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 427174.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.988

PP5

Variant 1-171114339-G-T is Pathogenic according to our data. Variant chr1-171114339-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 16311.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
FMO3	NM_001002294.3 link	c.1160G>T	p.Arg387Leu	missense_variant	Exon 7 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.1160G>T	p.Arg387Leu	missense_variant	Exon 7 of 9	1	NM_001002294.3	ENSP00000356729.4		P31513

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00

AC:

AN:

246470

AF XY:

0.00

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1460998

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726800

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33458

American (AMR)

AF:

0.00

AC:

AN:

44656

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39668

South Asian (SAS)

AF:

0.0000116

AC:

AN:

86228

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53308

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111462

Other (OTH)

AF:

0.00

AC:

AN:

60330

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

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000442

Hom.:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

FMO3-related disorder

Pathogenic:1

Mar 31, 2023

PreventionGenetics, part of Exact Sciences

Significance:Likely pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The FMO3 c.1160G>T variant is predicted to result in the amino acid substitution p.Arg387Leu. This variant was reported in the homozygous state in an individual with trimethylaminuria (Subject 5 in Akerman et al. 1999. PubMed ID: 10479479). This variant has not been reported in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Of note, another variant impacting the same amino acid residue (p.Arg387His) has also been documented in the homozygous state in a patient with trimethylaminuria (Kılıç. 2017. PubMed ID: 29745129). Based on this evidence, the c.1160G>T (p.Arg387Leu) variant is interpreted as likely pathogenic. -

Trimethylaminuria

Pathogenic:1

Sep 01, 1999

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

not specified

Uncertain:1

Jan 15, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: FMO3 c.1160G>T (p.Arg387Leu) results in a non-conservative amino acid change located in the FAD/NAD(P)-binding domain (IPR036188) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The frequency data for this variant in gnomAD is considered unreliable, as metrics indicate poor data quality at this position. c.1160G>T has been reported in the literature in one individual affected with Trimethylaminuria (Akerman_1999). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 10479479). ClinVar contains an entry for this variant (Variation ID: 16311). Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.86

BayesDel_addAF

Pathogenic

0.33

BayesDel_noAF

Pathogenic

0.24

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.093

Eigen

Uncertain

0.56

Eigen_PC

Uncertain

0.46

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.85

M_CAP

Uncertain

0.21

MetaRNN

Pathogenic

0.99

MetaSVM

Uncertain

0.059

MutationAssessor

Pathogenic

3.3

PhyloP100

7.5

PrimateAI

Benign

0.39

PROVEAN

Pathogenic

-6.3

REVEL

Pathogenic

0.70

Sift

Uncertain

0.0010

Sift4G

Pathogenic

0.0010

Polyphen

1.0

Vest4

0.94

MutPred

0.98

Loss of MoRF binding (P = 0.0124);

MVP

0.76

MPC

0.31

ClinPred

1.0

GERP RS

3.0

Varity_R

0.90

gMVP

0.90

Mutation Taster

=2/98

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over