rs863223766

Variant names:

• chr15-67165065-A-G
• rs863223766
• NM_005902.4:c.377A>G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_005902.4(SMAD3):​c.377A>G​(p.His126Arg) 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. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 34)
• Consequence: SMAD3 NM_005902.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 9.11

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the SMAD3 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 29 curated pathogenic missense variants (we use a threshold of 10). The gene has 14 curated benign missense variants. Gene score misZ: 3.4782 (above the threshold of 3.09). Trascript score misZ: 4.3526 (above the threshold of 3.09). GenCC associations: The gene is linked to familial thoracic aortic aneurysm and aortic dissection, aneurysm-osteoarthritis syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD3	NM_005902.4	c.377A>G	p.His126Arg	missense_variant	Exon 2 of 9	ENST00000327367.9	NP_005893.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD3	ENST00000327367.9	c.377A>G	p.His126Arg	missense_variant	Exon 2 of 9	1	NM_005902.4	ENSP00000332973.4

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 38

GnomAD4 genome Cov.: 34

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Apr 20, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 SMAD3 protein function. This sequence change replaces histidine, which is basic and polar, with arginine, which is basic and polar, at codon 126 of the SMAD3 protein (p.His126Arg). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with SMAD3-related conditions. ClinVar contains an entry for this variant (Variation ID: 213802). -

not provided Uncertain:1

Nov 27, 2017

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.His126Arg (CAC>CGC): c.377 A>G in exon 2 of the SMAD3 gene (NM_005902.3). A variant of unknown significance has been identified in the SMAD3 gene. The H126R variant has not been published as a mutation, nor has it been reported as a benign polymorphism to our knowledge. The H126R variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. Furthermore, this substitution occurs at a position that is conserved across species and in silico analysis predicts this variant is probably damaging to the protein structure/function. However, the H126R variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. Additionally, missense mutations in nearby residues have not been reported, indicating that this region of the protein may tolerate change. Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic mutation or a rare benign variant. This variant was found in TAAD,TAADV2-1 -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.54	D
BayesDel_noAF	Pathogenic	0.54
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	.;D;D;.;D;.;.
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Pathogenic	0.98	D;D;D;D;D;D;D
M_CAP	Pathogenic	0.71	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	3.8	.;H;.;.;.;.;.
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-7.7	D;D;D;D;D;D;D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;D;D;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D;D
Polyphen		0.97	.;D;.;.;.;.;.
Vest4		0.99, 0.99, 0.99
MutPred		0.95		.;Loss of phosphorylation at Y127 (P = 0.1103);.;.;.;.;.;
MVP		0.99
MPC		2.6
ClinPred		1.0	D
GERP RS		4.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.99
gMVP		0.98

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: rs863223766; hg19: chr15-67457403; COSMIC: COSV59291185; COSMIC: COSV59291185;