Genetic Variant SMAD3:c.-5delC (chr15-67066146-TC-T) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_005902.4(SMAD3):c.-5delC variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★).

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 7.0e-7 ( 0 hom. )

Failed GnomAD Quality Control

Consequence

SMAD3
NM_005902.4 5_prime_UTR

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 0.106

Publications

0 publications found

Variant links:

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

SMAD3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene	Transcript	HGVSc	Effect	Exon rank	MANE	Protein	UniProt
SMAD3	NM_005902.4 link	c.-5delC	5_prime_UTR_variant	Exon 1 of 9	ENST00000327367.9	NP_005893.1	P84022-1A0A024R5Z3Q9P0T0
SMAD3	NM_001407011.1 link	c.-5delC	5_prime_UTR_variant	Exon 1 of 10		NP_001393940.1
SMAD3	NM_001407012.1 link	c.-5delC	5_prime_UTR_variant	Exon 1 of 8		NP_001393941.1
SMAD3	NM_001407013.1 link	c.-5delC	5_prime_UTR_variant	Exon 1 of 8		NP_001393942.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD3	ENST00000327367.9 link	c.-5delC		5_prime_UTR_variant	Exon 1 of 9	1	NM_005902.4	ENSP00000332973.4		P84022-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

Data not reliable, filtered out with message: AS_VQSR

AF:

7.00e-7

AC:

AN:

1428582

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

707870

show subpopulations

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR)

AF:

0.00

AC:

AN:

32672

American (AMR)

AF:

0.00

AC:

AN:

40208

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25554

East Asian (EAS)

AF:

0.00

AC:

AN:

37964

South Asian (SAS)

AF:

0.00

AC:

AN:

82264

European-Finnish (FIN)

AF:

0.00

AC:

AN:

50124

Middle Eastern (MID)

AF:

0.00

AC:

AN:

4228

European-Non Finnish (NFE)

AF:

9.12e-7

AC:

AN:

1096560

Other (OTH)

AF:

0.00

AC:

AN:

59008

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.225

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

LINK: link

Submissions by phenotype

Aneurysm-osteoarthritis syndrome

Uncertain:1

Aug 15, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant deletes one nucleotide in the 3' untranslated region of the SMAD3 gene. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with SMAD3-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

PhyloP100

0.11

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over