NM_005902.4:c.-1C>T

Variant names:

• chr15-67066154-C-T
• rs770457783
• NM_005902.4:c.-1C>T

Variant summary

Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_Moderate BS2

The NM_005902.4(SMAD3):​c.-1C>T variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000125 in 1,439,288 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000013 (0 hom.)
• Consequence: SMAD3 NM_005902.4 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.23

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_benign. Variant got -6 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.37).
• BS2: High AC in GnomAdExome4 at 18 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD3	NM_005902.4	c.-1C>T		5_prime_UTR_variant	Exon 1 of 9	ENST00000327367.9	NP_005893.1
SMAD3	NM_001407011.1	c.-1C>T		5_prime_UTR_variant	Exon 1 of 10		NP_001393940.1
SMAD3	NM_001407012.1	c.-1C>T		5_prime_UTR_variant	Exon 1 of 8		NP_001393941.1
SMAD3	NM_001407013.1	c.-1C>T		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	c.-1C>T		5_prime_UTR_variant	Exon 1 of 9	1	NM_005902.4	ENSP00000332973.4
SMAD3	ENST00000560424	c.-1C>T		5_prime_UTR_variant	Exon 1 of 10	3		ENSP00000455540.2
SMAD3	ENST00000559460.6	c.-110+2210C>T		intron_variant	Intron 1 of 8	4		ENSP00000453082.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000188 AC: 4 AN: 212458 Hom.: 0 AF XY: 0.00000869 AC XY: 1 AN XY: 115106

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000961

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000108

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000125 AC: 18 AN: 1439288 Hom.: 0 Cov.: 32 AF XY: 0.0000126 AC XY: 9 AN XY: 713862

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000716

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000127

Gnomad4 OTH exome AF: 0.0000168

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000189

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:3

Feb 09, 2021

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 28, 2022

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.-1C>T variant is located in the 5' untranslated region (5’ UTR) of the SMAD3 gene. This variant results from a C to T substitution 1 nucleotide upstream from the first translated codon. This variant was reported in a thoracic aortic aneurysm and dissection (TAAD) cohort; however, clinical details were limited (Arnaud P et al. Genet Med, 2019 09;21:2015-2024). Based on nucleotide sequence alignment, this position is well conserved in available vertebrate species. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Nov 08, 2022

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant changes a single nucleotide in the 5' untranslated region of the SMAD3 gene. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with nonsyndromic heritable thoracic aortic aneurysms and dissections (PMID: 30739908). This variant has been identified in 4/212458 chromosomes 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. -

not provided Uncertain:1

Oct 15, 2015

Eurofins Ntd Llc (ga)

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.37
CADD	Benign	22
DANN	Benign	0.96

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: rs770457783; hg19: chr15-67358492;