NM_001002294.3:c.35T>C

Variant names:

• chr1-171092693-T-C
• NM_001002294.3:c.35T>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_001002294.3(FMO3):​c.35T>C​(p.Val12Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,834 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: FMO3 NM_001002294.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.638
• Publications: 0 publications found

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)

FMO1-AS1 (HGNC:40240):

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.22687683).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001002294.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FMO3	NM_001002294.3	MANE Select	c.35T>C	p.Val12Ala	missense	Exon 2 of 9	NP_001002294.1	A0A024R8Z4
	FMO3	NM_006894.6		c.35T>C	p.Val12Ala	missense	Exon 2 of 9	NP_008825.4
	FMO3	NM_001319174.2		c.35T>C	p.Val12Ala	missense	Exon 2 of 8	NP_001306103.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	FMO3	ENST00000367755.9	TSL:1 MANE Select	c.35T>C	p.Val12Ala	missense	Exon 2 of 9	ENSP00000356729.4	P31513
	FMO3	ENST00000479749.1	TSL:5	c.35T>C	p.Val12Ala	missense	Exon 2 of 6	ENSP00000477451.1	V9GZ60
	FMO3	ENST00000534514.1	TSL:1	n.118T>C		non_coding_transcript_exon	Exon 2 of 3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461834 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727222

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5758

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111978

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Uncertain significance

Revision: criteria provided, single submitter

Pathogenic	VUS	Benign	Condition
-	1	-	Inborn genetic diseases (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.37
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Benign	-0.53
CADD	Benign	18
DANN	Benign	0.96
DEOGEN2	Benign	0.013	T
Eigen	Benign	-0.61
Eigen_PC	Benign	-0.52
FATHMM_MKL	Benign	0.031	N
LIST_S2	Benign	0.82	T
M_CAP	Benign	0.0087	T
MetaRNN	Benign	0.23	T
MetaSVM	Benign	-1.1	T
MutationAssessor	Benign	1.3	L
PhyloP100		-0.64
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.2	N
REVEL	Benign	0.10
Sift	Benign	0.31	T
Sift4G	Benign	0.55	T
Polyphen		0.053	B
Vest4		0.096
MutPred		0.77		Gain of disorder (P = 0.0681)
MVP		0.34
MPC		0.11
ClinPred		0.088	T
GERP RS		3.3
Varity_R		0.13
gMVP		0.46
Mutation Taster		=92/8	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

hg19: chr1-171061834;