chr18-51058437-G-A

Variant names:

• chr18-51058437-G-A
• rs772028872
• NM_005359.6:c.885G>A

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Moderate BP6 BP7

The NM_005359.6(SMAD4):​c.885G>A​(p.Pro295Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,610,512 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 Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. P295P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000067 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: SMAD4 NM_005359.6 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:6
• Conservation: PhyloP100: 2.92
• Publications: 3 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

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.4).
• BP6: Variant 18-51058437-G-A is Benign according to our data. Variant chr18-51058437-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 484793.
• BP7: Synonymous conserved (PhyloP=2.92 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_005359.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	NM_005359.6	MANE Select	c.885G>A	p.Pro295Pro	synonymous	Exon 7 of 12	NP_005350.1
	SMAD4	NM_001407041.1		c.885G>A	p.Pro295Pro	synonymous	Exon 7 of 12	NP_001393970.1
	SMAD4	NM_001407042.1		c.885G>A	p.Pro295Pro	synonymous	Exon 7 of 12	NP_001393971.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	ENST00000342988.8	TSL:5 MANE Select	c.885G>A	p.Pro295Pro	synonymous	Exon 7 of 12	ENSP00000341551.3
	SMAD4	ENST00000591126.5	TSL:1	n.2886G>A		non_coding_transcript_exon	Exon 3 of 8
	SMAD4	ENST00000714264.1		c.885G>A	p.Pro295Pro	synonymous	Exon 7 of 12	ENSP00000519545.1

Frequencies

GnomAD3 genomes AF: 0.00000668 AC: 1 AN: 149694 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.000104

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251436 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000462

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1460818 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726824

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86236

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5646

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111164

Other (OTH) AF: 0.0000166 AC: 1 AN: 60350

GnomAD4 genome AF: 0.00000668 AC: 1 AN: 149694 Hom.: 0 Cov.: 32 AF XY: 0.0000137 AC XY: 1 AN XY: 72738

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

African (AFR) AF: 0.00 AC: 0 AN: 40766

American (AMR) AF: 0.00 AC: 0 AN: 15020

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3462

East Asian (EAS) AF: 0.00 AC: 0 AN: 5128

South Asian (SAS) AF: 0.00 AC: 0 AN: 4752

European-Finnish (FIN) AF: 0.000104 AC: 1 AN: 9588

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 304

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67710

Other (OTH) AF: 0.00 AC: 0 AN: 2054

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.0000293 Hom.: 0

ClinVar

ClinVar submissions as Germline

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	-	2	Hereditary cancer-predisposing syndrome (2)
-	-	1	Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)
-	-	1	Juvenile polyposis syndrome (1)
-	-	1	Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome (1)
-	1	-	not provided (1)
-	-	1	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.40
CADD	Benign	16
DANN	Benign	0.71
PhyloP100		2.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs772028872; hg19: chr18-48584807; COSMIC: COSV100748031; COSMIC: COSV100748031;