18-51030256-C-G

Variant names:

• chr18-51030256-C-G
• rs886053886
• NM_005359.6:c.-495C>G

Variant summary

Our verdict is Benign. The variant received -7 ACMG points: 0P and 7B. BP4_Moderate BS1_Supporting BS2

The NM_005359.6(SMAD4):​c.-495C>G variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000341 in 152,348 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: 𝑓 0.00034 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SMAD4 NM_005359.6 5_prime_UTR
• Clinical Significance: Uncertain significance criteria provided, single submitter U:3
• Conservation: PhyloP100: 0.234
• Publications: 0 publications found

Genes affected

SMAD4 (HGNC:6770): (SMAD family member 4) This gene encodes a member of the Smad family of signal transduction proteins. Smad proteins are phosphorylated and activated by transmembrane serine-threonine receptor kinases in response to transforming growth factor (TGF)-beta signaling. The product of this gene forms homomeric complexes and heteromeric complexes with other activated Smad proteins, which then accumulate in the nucleus and regulate the transcription of target genes. This protein binds to DNA and recognizes an 8-bp palindromic sequence (GTCTAGAC) called the Smad-binding element (SBE). The protein acts as a tumor suppressor and inhibits epithelial cell proliferation. It may also have an inhibitory effect on tumors by reducing angiogenesis and increasing blood vessel hyperpermeability. The encoded protein is a crucial component of the bone morphogenetic protein signaling pathway. The Smad proteins are subject to complex regulation by post-translational modifications. Mutations or deletions in this gene have been shown to result in pancreatic cancer, juvenile polyposis syndrome, and hereditary hemorrhagic telangiectasia syndrome. [provided by RefSeq, May 2022]

SMAD4 Gene-Disease associations (from GenCC):

• juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen, Genomics England PanelApp, G2P, PanelApp Australia
• Myhre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: ClinGen, Orphanet, G2P, Labcorp Genetics (formerly Invitae)
• generalized juvenile polyposis/juvenile polyposis coli

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp
• juvenile polyposis syndrome

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• familial thoracic aortic aneurysm and aortic dissection

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hereditary hemorrhagic telangiectasia

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• pulmonary arterial hypertension

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ENSG00000267699 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -7 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.24).
• BS1: Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000341 (52/152348) while in subpopulation NFE AF = 0.0005 (34/68022). AF 95% confidence interval is 0.000368. There are 0 homozygotes in GnomAd4. There are 31 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High AC in GnomAd4 at 52 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
SMAD4	NM_005359.6	c.-495C>G		5_prime_UTR_variant	Exon 1 of 12	ENST00000342988.8	NP_005350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8	c.-495C>G		5_prime_UTR_variant	Exon 1 of 12	5	NM_005359.6	ENSP00000341551.3
ENSG00000267699	ENST00000590722.2	n.158-16664C>G		intron_variant	Intron 2 of 8	2		ENSP00000465737.1

Frequencies

GnomAD3 genomes AF: 0.000342 AC: 52 AN: 152232 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.000288

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00113

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000500

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 592 Hom.: 0 Cov.: 0 AF XY: 0.00 AC XY: 0 AN XY: 368

African (AFR) AF: 0.00 AC: 0 AN: 6

American (AMR) AF: 0.00 AC: 0 AN: 2

Ashkenazi Jewish (ASJ) AC: 0 AN: 0

East Asian (EAS) AF: 0.00 AC: 0 AN: 4

South Asian (SAS) AF: 0.00 AC: 0 AN: 4

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 430

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 2

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 136

Other (OTH) AF: 0.00 AC: 0 AN: 8

GnomAD4 genome AF: 0.000341 AC: 52 AN: 152348 Hom.: 0 Cov.: 32 AF XY: 0.000416 AC XY: 31 AN XY: 74498

African (AFR) AF: 0.0000481 AC: 2 AN: 41584

American (AMR) AF: 0.000196 AC: 3 AN: 15314

Ashkenazi Jewish (ASJ) AF: 0.000288 AC: 1 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5176

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00113 AC: 12 AN: 10630

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.000500 AC: 34 AN: 68022

Other (OTH) AF: 0.00 AC: 0 AN: 2112

Alfa AF: 0.000847 Hom.: 0

Bravo AF: 0.000215

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, single submitter

Submissions by phenotype

Myhre syndrome Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Generalized juvenile polyposis/juvenile polyposis coli Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.24
CADD	Benign	17
DANN	Benign	0.91
PhyloP100		0.23
PromoterAI		-0.048	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs886053886; hg19: chr18-48556626;