chr18-51048761-C-T

Variant names:

• chr18-51048761-C-T
• rs1248541873
• NM_005359.6:c.325C>T

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.325C>T​(p.Leu109Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000659 in 151,730 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. L109L) has been classified as Likely benign.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: SMAD4 NM_005359.6 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:5
• Conservation: PhyloP100: 1.76
• 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: ClinGen, PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp
• Myhre syndrome

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

  Inheritance: AD Classification: STRONG, SUPPORTIVE Submitted by: Genomics England PanelApp, Orphanet
• 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: 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=-0.33).
• BP6: Variant 18-51048761-C-T is Benign according to our data. Variant chr18-51048761-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 492478.
• BP7: Synonymous conserved (PhyloP=1.76 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

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	NM_005359.6	MANE Select	c.325C>T	p.Leu109Leu	synonymous	Exon 3 of 12	NP_005350.1	Q13485
	SMAD4	NM_001407041.1		c.325C>T	p.Leu109Leu	synonymous	Exon 3 of 12	NP_001393970.1	A0A024R274
	SMAD4	NM_001407042.1		c.325C>T	p.Leu109Leu	synonymous	Exon 3 of 12	NP_001393971.1	Q13485

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	SMAD4	ENST00000342988.8	TSL:5 MANE Select	c.325C>T	p.Leu109Leu	synonymous	Exon 3 of 12	ENSP00000341551.3	Q13485
	ENSG00000267699	ENST00000590722.2	TSL:2	n.*348C>T		non_coding_transcript_exon	Exon 4 of 9	ENSP00000465737.1	E7EUB6
	ENSG00000267699	ENST00000590722.2	TSL:2	n.*348C>T		3_prime_UTR	Exon 4 of 9	ENSP00000465737.1	E7EUB6

Frequencies

GnomAD3 genomes AF: 0.00000659 AC: 1 AN: 151730 Hom.: 0 Cov.: 33

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: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000659 AC: 1 AN: 151730 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74132

African (AFR) AF: 0.00 AC: 0 AN: 41306

American (AMR) AF: 0.00 AC: 0 AN: 15220

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5136

South Asian (SAS) AF: 0.00 AC: 0 AN: 4744

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10584

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

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67954

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
-	1	1	not provided (2)
-	-	1	Hereditary cancer-predisposing syndrome (1)
-	-	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)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.33
CADD	Benign	9.5
DANN	Benign	0.75
PhyloP100		1.8
Mutation Taster		=99/1	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: rs1248541873; hg19: chr18-48575131; COSMIC: COSV100748367; COSMIC: COSV100748367;