18-51076773-A-G

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1PM2PP2BP4

The NM_005359.6(SMAD4):c.1444A>G(p.Ile482Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,454,780 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: not found (cov: 32)

Exomes 𝑓: 0.0000014 ( 0 hom. )

Consequence

SMAD4
NM_005359.6 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 7.31

Variant links:

Genes affected

SMAD4 (HGNC:6770): (SMAD family member 4) This gene encodes a member of the Smad family of signal transduction proteins. Smad proteins are phosphorylated and activated by transmembrane serine-threonine receptor kinases in response to transforming growth factor (TGF)-beta signaling. The product of this gene forms homomeric complexes and heteromeric complexes with other activated Smad proteins, which then accumulate in the nucleus and regulate the transcription of target genes. This protein binds to DNA and recognizes an 8-bp palindromic sequence (GTCTAGAC) called the Smad-binding element (SBE). The protein acts as a tumor suppressor and inhibits epithelial cell proliferation. It may also have an inhibitory effect on tumors by reducing angiogenesis and increasing blood vessel hyperpermeability. The encoded protein is a crucial component of the bone morphogenetic protein signaling pathway. The Smad proteins are subject to complex regulation by post-translational modifications. Mutations or deletions in this gene have been shown to result in pancreatic cancer, juvenile polyposis syndrome, and hereditary hemorrhagic telangiectasia syndrome. [provided by RefSeq, May 2022]

SMAD4 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 4 ACMG points.

PM1

In a domain MH2 (size 229) in uniprot entity SMAD4_HUMAN there are 40 pathogenic changes around while only 2 benign (95%) in NM_005359.6

PM2

Very rare variant in population databases, with high coverage;

PP2

Missense variant in the SMAD4 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 36 curated pathogenic missense variants (we use a threshold of 10). The gene has 52 curated benign missense variants. Gene score misZ: 4.1308 (above the threshold of 3.09). Trascript score misZ: 4.9346 (above the threshold of 3.09). GenCC associations: The gene is linked to familial thoracic aortic aneurysm and aortic dissection, generalized juvenile polyposis/juvenile polyposis coli, hereditary hemorrhagic telangiectasia, Myhre syndrome, pulmonary arterial hypertension, juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome, juvenile polyposis syndrome.

BP4

Computational evidence support a benign effect (MetaRNN=0.3470998).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD4	NM_005359.6 link	c.1444A>G	p.Ile482Val	missense_variant	Exon 11 of 12	ENST00000342988.8	NP_005350.1	Q13485A0A024R274
SMAD4	NM_001407041.1 link	c.1444A>G	p.Ile482Val	missense_variant	Exon 11 of 12		NP_001393970.1
SMAD4	NM_001407042.1 link	c.1444A>G	p.Ile482Val	missense_variant	Exon 11 of 12		NP_001393971.1
SMAD4	NR_176265.1 link	n.1982A>G		non_coding_transcript_exon_variant	Exon 11 of 13

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8 link	c.1444A>G	p.Ile482Val	missense_variant	Exon 11 of 12	5	NM_005359.6	ENSP00000341551.3		Q13485

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.00000402

AC:

AN:

248472

Hom.:

AF XY:

0.00000744

AC XY:

AN XY:

134350

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.00000137

AC:

AN:

1454780

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

723284

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:

9.03e-7

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

Cov.:

Alfa

AF:

0.000111

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection

Uncertain:1

Feb 10, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.I482V variant (also known as c.1444A>G), located in coding exon 10 of the SMAD4 gene, results from an A to G substitution at nucleotide position 1444. The isoleucine at codon 482 is replaced by valine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

Uncertain:1

Dec 18, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces isoleucine with valine at codon 482 of the SMAD4 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with SMAD4-related disorders in the literature. This variant has been identified in 1/248472 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Juvenile polyposis syndrome

Uncertain:1

Apr 16, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 482 of the SMAD4 protein (p.Ile482Val). This variant is present in population databases (no rsID available, gnomAD 0.0009%). This variant has not been reported in the literature in individuals affected with SMAD4-related conditions. ClinVar contains an entry for this variant (Variation ID: 221073). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on SMAD4 protein function. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.15

BayesDel_addAF

Pathogenic

0.18

BayesDel_noAF

Uncertain

0.020

CADD

Benign

DANN

Benign

0.97

DEOGEN2

Uncertain

0.71

D;D;D;.

Eigen

Benign

-0.012

Eigen_PC

Benign

0.22

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.95

.;D;D;D

M_CAP

Uncertain

0.13

MetaRNN

Benign

0.35

T;T;T;T

MetaSVM

Uncertain

0.38

MutationAssessor

Benign

0.94

L;L;.;.

PrimateAI

Uncertain

0.75

PROVEAN

Benign

-0.31

N;N;.;.

REVEL

Uncertain

0.32

Sift

Benign

0.52

T;T;.;.

Sift4G

Benign

0.32

T;T;T;T

Polyphen

0.0020

B;B;.;.

Vest4

0.43

MutPred

0.44

Gain of helix (P = 0.0696);Gain of helix (P = 0.0696);.;.;

MVP

0.76

MPC

1.3

ClinPred

0.26

GERP RS

5.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.28

gMVP

0.64

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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