15-67181396-G-C

Variant names:

• chr15-67181396-G-C
• rs1057524127
• NM_005902.4:c.814G>C

Variant summary

Our verdict is Likely pathogenic. The variant received 9 ACMG points: 9P and 0B. PM1 PM2 PP3_Strong PP5

The NM_005902.4(SMAD3):​c.814G>C​(p.Gly272Arg) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 14/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Synonymous variant affecting the same amino acid position (i.e. G272G) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMAD3 NM_005902.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:2 U:1
• Conservation: PhyloP100: 9.87
• Publications: 2 publications found

Genes affected

SMAD3 (HGNC:6769): (SMAD family member 3) The SMAD family of proteins are a group of intracellular signal transducer proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. The SMAD3 protein functions in the transforming growth factor-beta signaling pathway, and transmits signals from the cell surface to the nucleus, regulating gene activity and cell proliferation. This protein forms a complex with other SMAD proteins and binds DNA, functioning both as a transcription factor and tumor suppressor. Mutations in this gene are associated with aneurysms-osteoarthritis syndrome and Loeys-Dietz Syndrome 3. [provided by RefSeq, May 2022]

SMAD3 Gene-Disease associations (from GenCC):

• aneurysm-osteoarthritis syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: PanelApp Australia, Genomics England PanelApp, Orphanet, G2P, ClinGen, Labcorp Genetics (formerly Invitae)
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: Orphanet, ClinGen

ACMG classification

Our verdict: Likely_pathogenic. The variant received 9 ACMG points.

• PM1: In a hotspot region, there are 8 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 11 uncertain in NM_005902.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant 15-67181396-G-C is Pathogenic according to our data. Variant chr15-67181396-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 391534.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005902.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD3	NM_005902.4	MANE Select	c.814G>C	p.Gly272Arg	missense	Exon 6 of 9	NP_005893.1
	SMAD3	NM_001407011.1		c.814G>C	p.Gly272Arg	missense	Exon 6 of 10	NP_001393940.1
	SMAD3	NM_001145103.2		c.682G>C	p.Gly228Arg	missense	Exon 6 of 9	NP_001138575.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD3	ENST00000327367.9	TSL:1 MANE Select	c.814G>C	p.Gly272Arg	missense	Exon 6 of 9	ENSP00000332973.4
	SMAD3	ENST00000439724.7	TSL:1	c.682G>C	p.Gly228Arg	missense	Exon 6 of 9	ENSP00000401133.3
	SMAD3	ENST00000540846.6	TSL:1	c.499G>C	p.Gly167Arg	missense	Exon 6 of 9	ENSP00000437757.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:2 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Mar 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 272 of the SMAD3 protein (p.Gly272Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with clinical features of SMAD3-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 391534). Advanced modeling performed at Invitae incorporating data from internal and/or published experimental studies (Invitae) indicates that this missense variant is expected to disrupt SMAD3 function with a positive predictive value of 95%. 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.

Aneurysm-osteoarthritis syndrome Pathogenic:1

Jul 17, 2023

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Likely pathogenic. Following criteria are met: 0103 - Loss of function is a known mechanism of disease in this gene and is associated with Loeys-Dietz syndrome 3 (MIM#613795). However, dominant negative is also a proposed mechanism of disease in this gene associated with missense variants in the MH2 domain (PMID: 30661052). (I) 0107 - This gene is associated with autosomal dominant disease. (I) 0200 - Variant is predicted to result in a missense amino acid change from glycine to arginine. (I) 0251 - This variant is heterozygous. (I) 0301 - Variant is absent from gnomAD (both v2 and v3). (SP) 0501 - Missense variant consistently predicted to be damaging by multiple in silico tools or highly conserved with a major amino acid change. (SP) 0600 - Variant is located in the annotated MH2 domain (DECIPHER). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0808 - Previous reports of pathogenicity for this variant are conflicting. This variant is considered likely pathogenic and has been identified in two individuals with SMAD3-related conditions (Invitae personal communication). This variant has also been classified as a VUS by a clinical testing laboratory (ClinVar). (I) 0901 - This variant has strong evidence for segregation with disease. This variant has been shown to segregate with disease in six individuals from three families (VCGS internal data, Invitae personal communication). (SP) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign

not provided Uncertain:1

Dec 12, 2016

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

A novel variant of uncertain significance has been identified in the SMAD3 gene. The G272R variant has not beenpublished as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. It was not observedin approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome SequencingProject, indicating it is not a common benign variant in these populations. In addition, the G272R variant is anon-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differin polarity, charge, size and/or other properties. Moreover, this substitution occurs at a position that is conservedacross species, and in silico analysis predicts this variant is probably damaging to the protein structure/function.Nonetheless, this variant lacks observation in a significant number of affected individuals, segregation data, andfunctional evidence, all of which would further clarify pathogenicity.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	33
DANN	Pathogenic	1.0
DEOGEN2	Pathogenic	0.99	D
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.7	H
PhyloP100		9.9
PrimateAI	Pathogenic	0.95	D
PROVEAN	Pathogenic	-7.7	D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.99
MutPred		0.92		Gain of MoRF binding (P = 0.0079)
MVP		0.99
MPC		2.6
ClinPred		1.0	D
GERP RS		5.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.96
Mutation Taster		=3/97	disease causing

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

Other links and lift over

dbSNP: rs1057524127; hg19: chr15-67473734;