1-171114009-T-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_001002294.3(FMO3):c.830T>G(p.Val277Gly) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V277A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FMO3 NM_001002294.3 missense, splice_region
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.964

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]

(HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.056961507).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
FMO3	NM_001002294.3	c.830T>G	p.Val277Gly	missense_variant, splice_region_variant	7/9	ENST00000367755.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
FMO3	ENST00000367755.9	c.830T>G	p.Val277Gly	missense_variant, splice_region_variant	7/9	1	NM_001002294.3	P1
	ENST00000669750.1	n.533+54095A>C		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.081
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.51
Cadd	Benign	6.1
Dann	Benign	0.40
DEOGEN2	Benign	0.014	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.076	N
LIST_S2	Benign	0.015	T
M_CAP	Benign	0.0097	T
MetaRNN	Benign	0.057	T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.2	L
MutationTaster	Benign	1.0	N;N;N;N
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-1.3	N
REVEL	Benign	0.035
Sift	Benign	0.32	T
Sift4G	Benign	0.33	T
Polyphen		0.0	B
Vest4		0.16
MutPred		0.39		Loss of stability (P = 0.0029);
MVP		0.28
MPC		0.051
ClinPred		0.13	T
GERP RS		1.3
Varity_R		0.11
gMVP		0.43

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.14		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs2066530; hg19: chr1-171083149;