1-171103850-G-C

Variant names:

• chr1-171103850-G-C
• rs72549323
• NM_001002294.3:c.198G>C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PS1 PM2 PP3_Strong

The NM_001002294.3(FMO3):​c.198G>C​(p.Met66Ile) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FMO3 NM_001002294.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.81
• Publications: 15 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)

ENSG00000231424 (HGNC:40240):

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PS1: Transcript NM_001002294.3 (FMO3) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in ClinVar.
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.945

Transcripts

RefSeq

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

Ensembl

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

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.82
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.16
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.062	T;T
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.89	D;D
M_CAP	Benign	0.024	T
MetaRNN	Pathogenic	0.94	D;D
MetaSVM	Benign	-0.63	T
MutationAssessor	Uncertain	2.1	M;.
PhyloP100		6.8
PrimateAI	Uncertain	0.58	T
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		1.0	D
GERP RS		4.7
Varity_R		0.65
gMVP		0.71
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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

dbSNP: rs72549323; hg19: chr1-171072991;