Genetic Variant SMAD4:p.Ile347Val (chr18-51065506-A-G) – ACMG Classification: Benign (-9 pts)

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 2P and 11B. PM1BP4_ModerateBP6BS1BS2

The NM_005359.6(SMAD4):c.1039A>G(p.Ile347Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,613,952 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. 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. I347T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000014 ( 0 hom. )

Consequence

SMAD4
NM_005359.6 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:2

Conservation

PhyloP100: 0.955

Publications

4 publications found

Variant links:

COSMIC-nc: COSV100747983

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: Benign. The variant received -9 ACMG points.

PM1

In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 21 uncertain in NM_005359.6

BP4

Computational evidence support a benign effect (MetaRNN=0.10098234).

BP6

Variant 18-51065506-A-G is Benign according to our data. Variant chr18-51065506-A-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 460522.

BS1

Variant frequency is greater than expected in population sas. GnomAdExome4 allele frequency = 0.0000144 (21/1461792) while in subpopulation SAS AF = 0.0000812 (7/86254). AF 95% confidence interval is 0.0000376. There are 0 homozygotes in GnomAdExome4. There are 11 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High AC in GnomAdExome4 at 21 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005359.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SMAD4	NM_005359.6	MANE Select	c.1039A>G	p.Ile347Val	missense	Exon 9 of 12	NP_005350.1
SMAD4	NM_001407041.1		c.1039A>G	p.Ile347Val	missense	Exon 9 of 12	NP_001393970.1
SMAD4	NM_001407042.1		c.1039A>G	p.Ile347Val	missense	Exon 9 of 12	NP_001393971.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
SMAD4	ENST00000342988.8	TSL:5 MANE Select	c.1039A>G	p.Ile347Val	missense	Exon 9 of 12	ENSP00000341551.3
SMAD4	ENST00000591126.5	TSL:1	n.3040A>G		non_coding_transcript_exon	Exon 5 of 8
SMAD4	ENST00000714264.1		c.1120A>G	p.Ile374Val	missense	Exon 9 of 12	ENSP00000519545.1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152160

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:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000795

AC:

AN:

251440

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000144

AC:

AN:

1461792

Hom.:

Cov.:

AF XY:

0.0000151

AC XY:

AN XY:

727204

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33480

American (AMR)

AF:

0.00

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26132

East Asian (EAS)

AF:

0.00

AC:

AN:

39684

South Asian (SAS)

AF:

0.0000812

AC:

AN:

86254

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53420

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000108

AC:

AN:

1111944

Other (OTH)

AF:

0.0000166

AC:

AN:

60388

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152160

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74310

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41422

American (AMR)

AF:

0.00

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10592

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68038

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

ClinVar submissions as Germline

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Juvenile polyposis syndrome;C0796081:Myhre syndrome;C1832942:Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome;C2931038:Familial pancreatic carcinoma (2)

Hereditary cancer-predisposing syndrome (1)

Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)

Juvenile polyposis syndrome (1)

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome (1)

not provided (1)

not specified (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.053

BayesDel_addAF

Benign

-0.11

BayesDel_noAF

Benign

-0.21

CADD

Benign

(source)

DANN

Benign

0.95

DEOGEN2

Uncertain

0.66

Eigen

Benign

-0.51

Eigen_PC

Benign

-0.29

FATHMM_MKL

Uncertain

0.81

LIST_S2

Benign

0.80

M_CAP

Uncertain

0.093

MetaRNN

Benign

0.10

MetaSVM

Uncertain

0.20

MutationAssessor

Benign

-0.20

PhyloP100

0.95

PrimateAI

Benign

0.47

PROVEAN

Benign

0.21

REVEL

Uncertain

0.39

Sift

Benign

0.73

Sift4G

Benign

0.37

Polyphen

0.0010

Vest4

0.21

MutPred

0.43

Gain of phosphorylation at T349 (P = 0.1776)

MVP

0.58

MPC

0.38

ClinPred

0.085

GERP RS

3.4

Varity_R

0.040

gMVP

0.26

Mutation Taster

=83/17

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over