18-51065548-C-A

Position:

• chr18-51065548-C-A

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_005359.6(SMAD4):​c.1081C>A​(p.Arg361Ser) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R361C) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMAD4 NM_005359.6 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 4.79

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]

ACMG classification

Verdict is Pathogenic. Variant got 13 ACMG points.

• PM1: In a strand (size 4) in uniprot entity SMAD4_HUMAN there are 11 pathogenic changes around while only 0 benign (100%) in NM_005359.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr18-51065548-C-T is described in Lovd as [Pathogenic].
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMAD4. . Gene score misZ 4.1308 (greater than the threshold 3.09). Trascript score misZ 4.9346 (greater than threshold 3.09). GenCC has associacion of gene with familial thoracic aortic aneurysm and aortic dissection, generalized juvenile polyposis/juvenile polyposis coli, hereditary hemorrhagic telangiectasia, Myhre syndrome, pulmonary arterial hypertension, juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome, juvenile polyposis syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.993
• PP5: Variant 18-51065548-C-A is Pathogenic according to our data. Variant chr18-51065548-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 24822.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr18-51065548-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMAD4	NM_005359.6	c.1081C>A	p.Arg361Ser	missense_variant	9/12	ENST00000342988.8	NP_005350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8	c.1081C>A	p.Arg361Ser	missense_variant	9/12	5	NM_005359.6	ENSP00000341551	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Neoplasm of the large intestine Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

Database of Curated Mutations (DoCM)

Oct 02, 2014

- -

Juvenile polyposis syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 17, 2021

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 361 of the SMAD4 protein (p.Arg361Ser). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Arg361 amino acid residue in SMAD4. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 9214508, 9811934, 10764709, 11583957, 16613914, 17873119, 20101697). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. 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) performed at Invitae indicates that this missense variant is expected to disrupt SMAD4 protein function. ClinVar contains an entry for this variant (Variation ID: 24822). This missense change has been observed in individual(s) with juvenile polyposis (PMID: 15235019). This variant is not present in population databases (gnomAD no frequency). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;D;D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Pathogenic	0.99	.;D;D
M_CAP	Pathogenic	0.71	D
MetaRNN	Pathogenic	0.99	D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M;M;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-5.9	D;D;.
REVEL	Pathogenic	0.91
Sift	Pathogenic	0.0	D;D;.
Sift4G	Uncertain	0.027	D;D;D
Polyphen		1.0	D;D;.
Vest4		1.0
MutPred		0.97		Loss of catalytic residue at R361 (P = 0.0123);Loss of catalytic residue at R361 (P = 0.0123);.;
MVP		1.0
MPC		3.1
ClinPred		0.99	D
GERP RS		5.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.97

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

Other links and lift over

dbSNP: rs80338963; hg19: chr18-48591918; COSMIC: COSV61685418; COSMIC: COSV61685418;