18-51078416-A-G

Variant names:

• chr18-51078416-A-G
• rs753128184
• NM_005359.6:c.1608A>G

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The ENST00000342988.8(SMAD4):​c.1608A>G​(p.Leu536Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000805 in 1,614,102 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 Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. L536L) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000039 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: SMAD4 ENST00000342988.8 synonymous
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:10
• Conservation: PhyloP100: -0.144
• 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

ACMG classification

Our verdict: Benign. The variant received -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.59).
• BP6: Variant 18-51078416-A-G is Benign according to our data. Variant chr18-51078416-A-G is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 460542.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.144 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.0000394 (6/152222) while in subpopulation AFR AF = 0.000145 (6/41462). AF 95% confidence interval is 0.0000628. There are 0 homozygotes in GnomAd4. There are 3 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High AC in GnomAd4 at 6 AD gene.

Variant Effect in Transcripts

ACMG analysis was done for transcript: ENST00000342988.8. 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.1608A>G	p.Leu536Leu	synonymous	Exon 12 of 12	NP_005350.1
	SMAD4	NM_001407041.1		c.1608A>G	p.Leu536Leu	synonymous	Exon 12 of 12	NP_001393970.1
	SMAD4	NM_001407042.1		c.1608A>G	p.Leu536Leu	synonymous	Exon 12 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.1608A>G	p.Leu536Leu	synonymous	Exon 12 of 12	ENSP00000341551.3
	SMAD4	ENST00000591126.5	TSL:1	n.3609A>G		non_coding_transcript_exon	Exon 8 of 8
	SMAD4	ENST00000714264.1		c.1689A>G	p.Leu563Leu	synonymous	Exon 12 of 12	ENSP00000519545.1

Frequencies

GnomAD3 genomes AF: 0.0000394 AC: 6 AN: 152222 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000145

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: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000159 AC: 4 AN: 251440 AF XY: 0.0000147

Gnomad AFR exome AF: 0.000123

Gnomad AMR exome AF: 0.0000578

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461880 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727238

African (AFR) AF: 0.000149 AC: 5 AN: 33480

American (AMR) AF: 0.0000447 AC: 2 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53414

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60396

GnomAD4 genome AF: 0.0000394 AC: 6 AN: 152222 Hom.: 0 Cov.: 32 AF XY: 0.0000403 AC XY: 3 AN XY: 74372

African (AFR) AF: 0.000145 AC: 6 AN: 41462

American (AMR) AF: 0.00 AC: 0 AN: 15284

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10628

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68028

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.0000557 Hom.: 0

Bravo AF: 0.0000567

ClinVar

ClinVar submissions as Germline

Significance: Benign/Likely benign

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	-	2	Hereditary cancer-predisposing syndrome (2)
-	-	2	Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome (2)
-	-	1	Familial thoracic aortic aneurysm and aortic dissection (1)
-	-	1	Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection (1)
-	-	1	Juvenile polyposis syndrome (1)
-	-	1	not provided (1)
-	-	1	not specified (1)
-	-	1	SMAD4-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.59
CADD	Benign	1.4
DANN	Benign	0.61
PhyloP100		-0.14
Mutation Taster		=93/7	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: rs753128184; hg19: chr18-48604786;