rs387906855

Positions:

• chr15-67181370-C-G
• chr15-67181370-C-T

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PM1 PM2 PP2 PP3_Strong PP5

The NM_005902.4(SMAD3):​c.788C>G​(p.Pro263Arg) 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMAD3 NM_005902.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 7.80

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 Pathogenic. Variant got 10 ACMG points.

• PM1: In a domain MH2 (size 193) in uniprot entity SMAD3_HUMAN there are 36 pathogenic changes around while only 0 benign (100%) in NM_005902.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMAD3. . Gene score misZ 3.4782 (greater than the threshold 3.09). Trascript score misZ 4.3526 (greater than threshold 3.09). GenCC has associacion of gene with familial thoracic aortic aneurysm and aortic dissection, aneurysm-osteoarthritis syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.984
• PP5: Variant 15-67181370-C-G is Pathogenic according to our data. Variant chr15-67181370-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 213765.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMAD3	NM_005902.4	c.788C>G	p.Pro263Arg	missense_variant	6/9	ENST00000327367.9	NP_005893.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMAD3	ENST00000327367.9	c.788C>G	p.Pro263Arg	missense_variant	6/9	1	NM_005902.4	ENSP00000332973	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Feb 01, 2023

This variant disrupts the p.Pro263 amino acid residue in SMAD3. Other variant(s) that disrupt this residue have been observed in individuals with SMAD3-related conditions (PMID: 22167769, 30661052), which suggests that this may be a clinically significant amino acid residue. 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. ClinVar contains an entry for this variant (Variation ID: 213765). This missense change has been observed in individual(s) with SMAD3-related conditions (PMID: 30661052; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with arginine, which is basic and polar, at codon 263 of the SMAD3 protein (p.Pro263Arg). 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 14, 2016

p.Pro263Arg (CCC>CGC): c.788 C>G in exon 6 of the SMAD3 gene (NM_005902.3). While the Pro263Arg mutation in the SMAD3 gene has not been reported to our knowledge, a pathogenic variant affecting this same codon, Pro263Leu, has been reported in association with TAAD (van de Laar I et al., 2012). Additionally, pathogenic variants in nearby residues (Thr261Ile, Arg279Lys) have been reported in association with TAAD, further supporting the functional importance of this codon and this region of the protein. Pro263Arg results in a non-conservative amino acid substitution of a non-polar Proline with a positively charged Arginine at a position that is conserved across species. In silico analysis predicts Pro263Arg is damaging to the protein structure/function. Furthermore, Pro263Arg 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. This variant was found in TAAD -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.58	D
BayesDel_noAF	Pathogenic	0.60
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.99	D;.;D;.;.;D;.
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Uncertain	0.95	D
LIST_S2	Pathogenic	0.99	D;D;D;D;D;D;D
M_CAP	Pathogenic	0.71	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.0	H;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-8.6	D;D;D;D;D;D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D;D;D;D;D;D
Sift4G	Pathogenic	0.0010	D;D;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;.;.
Vest4		0.97
MutPred		0.87		Gain of phosphorylation at S266 (P = 0.0952);.;.;.;.;.;.;
MVP		0.99
MPC		2.5
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		0.90

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: rs387906855; hg19: chr15-67473708;