18-51076662-C-T

Variant names:

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_005359.6(SMAD4):c.1333C>T(p.Arg445*) variant causes a stop gained change. The variant allele was found at a frequency of 0.000000684 in 1,461,646 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R445R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

SMAD4
NM_005359.6 stop_gained

Scores

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:8O:1

Conservation

PhyloP100: 3.89

Publications

48 publications found

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 Gene-Disease associations (from GenCC):

juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp, G2P, PanelApp Australia
Myhre syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae)
generalized juvenile polyposis/juvenile polyposis coli
Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
juvenile polyposis syndrome
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
familial thoracic aortic aneurysm and aortic dissection
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
hereditary hemorrhagic telangiectasia
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
pulmonary arterial hypertension
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

SMAD4 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1

Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.

PM2

Very rare variant in population databases, with high coverage;

PP5

Variant 18-51076662-C-T is Pathogenic according to our data. Variant chr18-51076662-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 24850.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD4	NM_005359.6 link	c.1333C>T	p.Arg445*	stop_gained	Exon 11 of 12	ENST00000342988.8	NP_005350.1	Q13485A0A024R274
SMAD4	NM_001407041.1 link	c.1333C>T	p.Arg445*	stop_gained	Exon 11 of 12		NP_001393970.1
SMAD4	NM_001407042.1 link	c.1333C>T	p.Arg445*	stop_gained	Exon 11 of 12		NP_001393971.1
SMAD4	NR_176265.1 link	n.1871C>T		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.1333C>T	p.Arg445*	stop_gained	Exon 11 of 12	5	NM_005359.6	ENSP00000341551.3		Q13485

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251272

AF XY:

0.00000736

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 FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461646

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727110

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

33474

American (AMR)

AF:

0.00

AC:

AN:

44708

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53414

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111838

Other (OTH)

AF:

0.00

AC:

AN:

60384

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.375

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000396

Hom.:

ExAC

AF:

0.00000824

AC:

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:8Other:1

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Pathogenic:3

May 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

SMAD4: PVS1, PM2, PS4:Supporting -

Apr 10, 2018

GeneDx

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is denoted SMAD4 c.1333C>T at the cDNA level and p.Arg445Ter (R445X) at the protein level. The substitution creates a nonsense variant, which changes an Arginine to a premature stop codon (CGA>TGA), and is predicted to cause loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay. This variant has been reported in association with juvenile polyposis syndrome (Woodford-Richens 2000, Handra-Luca 2005, Andrabi 2011) and is considered pathogenic. -

Mar 27, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The SMAD4 c.1333C>T (p.Arg445*) variant causes the premature termination of SMAD4 protein synthesis. This variant has been reported in the published literature in individuals with juvenile polyposis syndrome (JPS) (PMID: 25931195 (2015), 21465659 (2011), 16152648 (2005), 10764709 (2000)), colorectal cancer (PMID: 37319387 (2023)), and oligoastrocytoma (PMID: 36451132 (2022)). This variant has also been shown to abrogate protein expression (PMID: 32719554 (2020)). The frequency of this variant in the general population, 0.000004 (1/251272 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is consistent with pathogenicity. Based on the available information, this variant is classified as pathogenic. -

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

Pathogenic:2

Feb 09, 2024

Myriad Genetics, Inc.

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered pathogenic. This variant creates a termination codon and is predicted to result in premature protein truncation. -

May 01, 2011

OMIM

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:literature only

- -

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

Pathogenic:1

Aug 27, 2021

Ambry Genetics

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.R445* pathogenic mutation (also known as c.1333C>T), located in coding exon 10 of the SMAD4 gene, results from a C to T substitution at nucleotide position 1333. This changes the amino acid from an arginine to a stop codon within coding exon 10. This mutation has been identified in multiple individuals with Juvenile Polyposis Syndrome (JPS) (Woodford-Richens K et al. Gut. 2000 May;46:656-60; Heald B et al. Am. J. Med. Genet. A. 2015 Aug;167A:1758-62; Handra-Luca A et al. Am. J. Med. Genet. A. 2005 Oct;138A:113-7). This mutation has also been reported in a patient with lower grade glioma from a cohort of 4034 cancer cases from The Cancer Genome Atlas (Lu C et al. Nat Commun, 2015 Dec;6:10086). Of note, this alteration is also designated as c.1363C>T in published literature. In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Gallbladder cancer

Pathogenic:1

Oct 30, 2020

Institute of Medical Sciences, Banaras Hindu University

Significance:Pathogenic

Review Status:no assertion criteria provided

Collection Method:research

- -

Juvenile polyposis syndrome

Pathogenic:1

May 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Pathogenic

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Arg445*) in the SMAD4 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in SMAD4 are known to be pathogenic (PMID: 16152648, 16436638, 22810475). This variant is present in population databases (rs377767360, gnomAD 0.0009%). This premature translational stop signal has been observed in individual(s) with juvenile polyposis syndrome (PMID: 10764709, 16152648, 21465659). ClinVar contains an entry for this variant (Variation ID: 24850). For these reasons, this variant has been classified as Pathogenic. -

Neoplasm

Other:1

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance:-

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.63

BayesDel_noAF

Pathogenic

0.63

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

Eigen

Pathogenic

0.88

Eigen_PC

Pathogenic

0.77

FATHMM_MKL

Uncertain

0.94

PhyloP100

3.9

Vest4

0.97

GERP RS

6.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=0/200

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.15

Details are displayed if max score is > 0.2

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

Publications

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over