18-51047066-C-T

Position:

chr18-51047066-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP6BS2

The NM_005359.6(SMAD4):c.20C>T(p.Thr7Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000645 in 1,613,528 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T7R) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000068 ( 0 hom. )

Consequence

SMAD4
NM_005359.6 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:13B:4

Conservation

PhyloP100: 5.97

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 Likely_benign. Variant got -4 ACMG points.

PP2

Missense variant where missense usually causes diseases, SMAD4

BP6

Variant 18-51047066-C-T is Benign according to our data. Variant chr18-51047066-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 183733.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=12, Benign=2}.

BS2

High AC in GnomAd4 at 5 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMAD4	NM_005359.6 linkuse as main transcript	c.20C>T	p.Thr7Met	missense_variant	2/12	ENST00000342988.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMAD4	ENST00000342988.8 linkuse as main transcript	c.20C>T	p.Thr7Met	missense_variant	2/12	5	NM_005359.6	P1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152114

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

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:

0.000189

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000441

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000517

AC:

AN:

251288

Hom.:

AF XY:

0.0000589

AC XY:

AN XY:

135810

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000544

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000462

Gnomad NFE exome

AF:

0.0000968

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000677

AC:

AN:

1461296

Hom.:

Cov.:

AF XY:

0.0000688

AC XY:

AN XY:

727010

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.000131

Gnomad4 NFE exome

AF:

0.0000792

Gnomad4 OTH exome

AF:

0.0000497

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152232

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74446

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000189

Gnomad4 NFE

AF:

0.0000441

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000135

Hom.:

Bravo

AF:

0.0000264

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.0000659

AC:

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:13Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Apr 10, 2023	This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Feb 05, 2024	This missense variant replaces threonine with methionine at codon 7 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with colorectal cancer (PMID: 25559809, 29684080). This variant has been identified in 15/282646 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 27, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

not provided

Uncertain:2Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Sep 17, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jun 28, 2023	In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 26343384, 25559809, 28873162, 29684080) -
Uncertain significance, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	May 09, 2023	The SMAD4 c.20C>T; p.Thr7Met variant (rs372316981), is reported in the literature in an individual with colorectal cancer (Chubb 2015). This variant is reported in ClinVar (Variation ID: 183733) and is found in the general population with an overall allele frequency of 0.005% (15/282646 alleles) in the Genome Aggregation Database. Computational analyses are uncertain whether this variant is neutral or deleterious (REVEL: 0.439). However, due to limited information, the clinical significance of the p.Thr7Met variant is uncertain at this time. References: Chubb D et al. Genetic diagnosis of high-penetrance susceptibility for colorectal cancer (CRC) is achievable for a high proportion of familial CRC by exome sequencing. J Clin Oncol. 2015 Feb 10;33(5):426-32. PMID: 25559809. -

Generalized juvenile polyposis/juvenile polyposis coli

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Nov 08, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 27, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 10, 2023	This missense variant replaces threonine with methionine at codon 7 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals affected with colorectal cancer (PMID: 25559809, 29684080). This variant has been identified in 15/282646 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. -
Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Sep 06, 2021	- -

Pulmonary arterial hypertension

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

John Welsh Cardiovascular Diagnostic Laboratory, Baylor College of Medicine

Sep 26, 2022

- -

SMAD4-related disorder

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 25, 2023

The SMAD4 c.20C>T variant is predicted to result in the amino acid substitution p.Thr7Met. This variant has been detected in at least one individual with a personal or family history of colon cancer (Chubb et al. 2015. PubMed ID: 25559809, Table A1). This variant is reported in 0.012% of alleles in individuals of European (Finnish) descent in gnomAD (http://gnomad.broadinstitute.org/variant/18-48573436-C-T). In ClinVar, this variant has conflicting interpretations, ranging from uncertain to benign (https://www.ncbi.nlm.nih.gov/clinvar/variation/183733/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Carcinoma of pancreas;C0796081:Myhre syndrome;C1832942:Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome;C1868081:Generalized juvenile polyposis/juvenile polyposis coli

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Juvenile polyposis syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 26, 2024

This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 7 of the SMAD4 protein (p.Thr7Met). This variant is present in population databases (rs372316981, gnomAD 0.01%). This missense change has been observed in individual(s) with a personal and/or family history of colon cancer (PMID: 25559809, 29684080). ClinVar contains an entry for this variant (Variation ID: 183733). 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. -

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Mar 19, 2024

Variant summary: SMAD4 c.20C>T (p.Thr7Met) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 6.4e-05 in 1613528 control chromosomes. The observed variant frequency is approximately 2.84 fold of the estimated maximal expected allele frequency for a pathogenic variant in SMAD4 causing Colon Cancer phenotype (2.3e-05), strongly suggesting that the variant is benign. c.20C>T has been reported in the literature in at-least one individual affected with Colon Cancer (Chubb_2015). These report(s) do not provide unequivocal conclusions about association of the variant with Colon and/or SMAD4-related Cancer. At-least one database (LOVD) publishes this variant as co-occuring with another variant 1244_1247delACAG in the SMAD4 gene. This co-occuring variant is annotated as SMAD4, c.1245_1248delCAGA (p.Asp415Glufs), a pathogenic variant in the ClinVar database. This provides supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 25559809). ClinVar contains an entry for this variant (Variation ID: 183733). Based on the evidence outlined above, the variant was classified as likely benign. -

Myhre syndrome

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 27, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

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

Benign:1

Benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 07, 2021

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.26

BayesDel_addAF

Uncertain

0.13

BayesDel_noAF

Pathogenic

0.15

CADD

Pathogenic

DANN

Uncertain

0.99

DEOGEN2

Benign

0.36

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

Eigen

Uncertain

0.66

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.97

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

M_CAP

Uncertain

0.14

MetaRNN

Uncertain

0.53

D;D;D;D;D;D;D;D

MetaSVM

Pathogenic

0.97

MutationTaster

Benign

1.0

D;D;D;D

PrimateAI

Pathogenic

0.79

Sift4G

Uncertain

0.026

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

Polyphen

1.0

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

Vest4

0.50, 0.47, 0.51

MVP

0.83

MPC

2.3

ClinPred

0.30

GERP RS

5.9

Varity_R

0.25

gMVP

0.48

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