18-51065419-A-G

Position:

chr18-51065419-A-G

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_005359.6(SMAD4):c.956-4A>G variant causes a splice region, splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000932 in 1,608,750 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

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

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

SMAD4
NM_005359.6 splice_region, splice_polypyrimidine_tract, intron

Scores

Splicing: ADA: 0.0003501

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:3

Conservation

PhyloP100: -0.302

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 Benign. Variant got -9 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.74).

BP6

Variant 18-51065419-A-G is Benign according to our data. Variant chr18-51065419-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 460574.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=2, Likely_benign=3}.

BS2

High AC in GnomAdExome4 at 14 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SMAD4	NM_005359.6 linkuse as main transcript	c.956-4A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		ENST00000342988.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
SMAD4	ENST00000342988.8 linkuse as main transcript	c.956-4A>G		splice_region_variant, splice_polypyrimidine_tract_variant, intron_variant		5	NM_005359.6	P1

Frequencies

GnomAD3 genomes

AF:

0.00000659

AC:

AN:

151774

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

GnomAD3 exomes

AF:

0.00000399

AC:

AN:

250898

Hom.:

AF XY:

0.00000737

AC XY:

AN XY:

135600

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:

0.00000881

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000961

AC:

AN:

1456976

Hom.:

Cov.:

AF XY:

0.00000966

AC XY:

AN XY:

724936

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:

0.0000126

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.00000659

AC:

AN:

151774

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74136

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:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 16, 2020

Variant summary: SMAD4 c.956-4A>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 4/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 4e-06 in 250898 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.956-4A>G in individuals affected with Juvenile Polyposis Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Three ClinVar submitters (evaluation after 2014) cite the variant as likely benign (n=2) or uncertain significance (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

May 19, 2020

The SMAD4 c.956-4A>G variant (rs1295343500), to our knowledge, is not reported in the medical literature but is reported in ClinVar (Variation ID: 460574). This variant is only observed on one allele in the Genome Aggregation Database, indicating it is not a common polymorphism. This is an intronic variant in a weakly conserved nucleotide, and computational analyses (Alamut v.2.11) predict that this variant does not alter splicing. However, due to limited information, the clinical significance of this variant is uncertain at this time. -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 01, 2022

This alteration is classified as likely 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. -

Hereditary cancer-predisposing syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Oct 05, 2016

- -

Juvenile polyposis syndrome

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 14, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.74

CADD

Benign

4.7

DANN

Benign

0.69

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00035

dbscSNV1_RF

Benign

0.020

SpliceAI score (max)

0.080

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