rs909530

Positions:

• chr1-171114034-C-A
• chr1-171114034-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_001002294.3(FMO3):​c.855C>A​(p.Asn285Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. 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. Synonymous variant affecting the same amino acid position (i.e. N285N) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: FMO3 NM_001002294.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.534

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_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
FMO3	NM_001002294.3	c.855C>A	p.Asn285Lys	missense_variant	7/9	ENST00000367755.9	NP_001002294.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
FMO3	ENST00000367755.9	c.855C>A	p.Asn285Lys	missense_variant	7/9	1	NM_001002294.3	ENSP00000356729	P1
	ENST00000669750.1	n.533+54070G>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Benign	-0.049	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	18
DANN	Uncertain	1.0
DEOGEN2	Benign	0.072	T
Eigen	Benign	-0.12
Eigen_PC	Benign	-0.34
FATHMM_MKL	Benign	0.25	N
LIST_S2	Uncertain	0.92	D
M_CAP	Benign	0.056	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Benign	-0.69	T
MutationAssessor	Pathogenic	3.1	M
MutationTaster	Benign	0.00011	P;P;P;P
PrimateAI	Uncertain	0.57	T
PROVEAN	Pathogenic	-5.0	D
REVEL	Uncertain	0.47
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.75
MutPred		0.80		Gain of methylation at N285 (P = 0.0143);
MVP		0.69
MPC		0.32
ClinPred		0.99	D
GERP RS		0.82
Varity_R		0.85
gMVP		0.77

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

Publications

LitVar

Other links and lift over

dbSNP: rs909530; hg19: chr1-171083174;