Genetic Variant SMTN:p.Ala2Val (chr22-31083263-C-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM1PM2BP4_Moderate

The NM_134269.3(SMTN):c.5C>T(p.Ala2Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000219 in 1,596,158 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000020 ( 0 hom. )

Consequence

SMTN
NM_134269.3 missense

Scores

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 1.52

Variant links:

Genes affected

SMTN (HGNC:11126): (smoothelin) This gene encodes a structural protein that is found exclusively in contractile smooth muscle cells. It associates with stress fibers and constitutes part of the cytoskeleton. This gene is localized to chromosome 22q12.3, distal to the TUPLE1 locus and outside the DiGeorge syndrome deletion. Alternative splicing of this gene results in multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2011]

SMTN links:

ENSG00000273387 (HGNC:):

ENSG00000273387 links:

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ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 2 ACMG points.

PM1

In a modified_residue N-acetylalanine (size 0) in uniprot entity SMTN_HUMAN

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.23812419).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMTN	NM_134269.3 link	c.5C>T	p.Ala2Val	missense_variant	Exon 2 of 21	ENST00000333137.12	NP_599031.1	P53814-5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMTN	ENST00000333137.12 link	c.5C>T	p.Ala2Val	missense_variant	Exon 2 of 21	1	NM_134269.3	ENSP00000329532.7		P53814-5

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152238

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000723

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD4 exome

AF:

0.0000201

AC:

AN:

1443920

Hom.:

Cov.:

AF XY:

0.0000181

AC XY:

AN XY:

716582

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000235

Gnomad4 OTH exome

AF:

0.0000502

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152238

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74372

show subpopulations

Gnomad4 AFR

AF:

0.0000723

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000580

Hom.:

Bravo

AF:

0.0000416

ExAC

AF:

0.00000832

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Oct 01, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.167C>T (p.A56V) alteration is located in exon 2 (coding exon 2) of the SMTN gene. This alteration results from a C to T substitution at nucleotide position 167, causing the alanine (A) at amino acid position 56 to be replaced by a valine (V). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.39

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.39

CADD

Benign

DANN

Pathogenic

1.0

DEOGEN2

Benign

0.050

.;T;.;.;.;T;.;.;.

Eigen

Benign

-0.031

Eigen_PC

Benign

-0.12

FATHMM_MKL

Uncertain

0.77

LIST_S2

Uncertain

0.86

D;T;D;D;T;T;T;T;D

M_CAP

Benign

0.031

MetaRNN

Benign

0.24

T;T;T;T;T;T;T;T;T

MetaSVM

Benign

-0.90

MutationAssessor

Benign

0.0

.;.;.;.;N;N;N;.;.

PrimateAI

Uncertain

0.56

PROVEAN

Uncertain

-3.4

D;D;N;N;N;N;N;.;.

REVEL

Benign

0.13

Sift

Uncertain

0.0070

D;D;D;D;D;D;D;.;.

Sift4G

Pathogenic

0.0

D;D;D;D;T;T;T;D;T

Polyphen

1.0, 1.0

.;.;.;.;.;D;D;.;.

Vest4

0.17, 0.27, 0.18, 0.30

MVP

0.10

MPC

0.48

ClinPred

0.39

GERP RS

2.1

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.11

gMVP

0.34

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over