NM_005359.6:c.787+2T>C

Variant names:

• chr18-51058246-T-C
• rs1909895611
• NM_005359.6:c.787+2T>C

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1_Moderate PS3 PM2 PP5_Very_Strong

The NM_005359.6(SMAD4):​c.787+2T>C variant causes a splice donor, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). ClinVar reports functional evidence for this variant: "SCV001220454: RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. Invitae" and additional evidence is available in ClinVar.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMAD4 NM_005359.6 splice_donor, intron
• Scores: Splicing: ADA: 0.9959
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 4.30
• Publications: 0 publications found

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), Genomics England PanelApp, PanelApp Australia, G2P, ClinGen
• Myhre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Labcorp Genetics (formerly Invitae), G2P, PanelApp Australia, Orphanet
• generalized juvenile polyposis/juvenile polyposis coli

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• 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

ENSG00000267699 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.07233273 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.8, offset of -24, new splice context is: ctgGTcagc. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PS3: PS3 evidence extracted from ClinVar submissions: SCV001220454: RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. Invitae; SCV002680853: RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data).
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-51058246-T-C is Pathogenic according to our data. Variant chr18-51058246-T-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 851605.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	NM_005359.6	MANE Select	c.787+2T>C		splice_donor intron	N/A	NP_005350.1	Q13485
	SMAD4	NM_001407041.1		c.787+2T>C		splice_donor intron	N/A	NP_001393970.1	A0A024R274
	SMAD4	NM_001407042.1		c.787+2T>C		splice_donor intron	N/A	NP_001393971.1	Q13485

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	ENST00000342988.8	TSL:5 MANE Select	c.787+2T>C		splice_donor intron	N/A	ENSP00000341551.3	Q13485
	SMAD4	ENST00000591126.5	TSL:1	n.2788+2T>C		splice_donor intron	N/A
	SMAD4	ENST00000714264.1		c.787+2T>C		splice_donor intron	N/A	ENSP00000519545.1	A0AAQ5BHY6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

ClinVar submissions

Significance: Likely pathogenic

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
1	-	-	Generalized juvenile polyposis/juvenile polyposis coli (1)
1	-	-	Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)
1	-	-	Juvenile polyposis syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.20
CADD	Pathogenic	34
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.93
FATHMM_MKL	Uncertain	0.92	D
PhyloP100		4.3
Mutation Taster		=3/97	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Benign	0.72
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.66		Position offset: 2
DS_DL_spliceai		0.96		Position offset: -2

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Other links and lift over

dbSNP: rs1909895611;

hg19: chr18-48584616;

COSMIC: COSV61687689;