18-51058149-G-C

Variant names:

• chr18-51058149-G-C
• rs759679579
• NM_005359.6:c.692G>C

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 2P and 3B. PM2 BP4_Moderate BP6

The NM_005359.6(SMAD4):​c.692G>C​(p.Gly231Ala) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G231V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.000059 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: SMAD4 NM_005359.6 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 4.38
• 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: 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 -1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.08838549).
• BP6: Variant 18-51058149-G-C is Benign according to our data. Variant chr18-51058149-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 421348.

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.692G>C	p.Gly231Ala	missense	Exon 6 of 12	NP_005350.1	Q13485
	SMAD4	NM_001407041.1		c.692G>C	p.Gly231Ala	missense	Exon 6 of 12	NP_001393970.1	A0A024R274
	SMAD4	NM_001407042.1		c.692G>C	p.Gly231Ala	missense	Exon 6 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.692G>C	p.Gly231Ala	missense	Exon 6 of 12	ENSP00000341551.3	Q13485
	SMAD4	ENST00000591126.5	TSL:1	n.2693G>C		non_coding_transcript_exon	Exon 2 of 8
	SMAD4	ENST00000714264.1		c.692G>C	p.Gly231Ala	missense	Exon 6 of 12	ENSP00000519545.1	A0AAQ5BHY6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.000744 AC: 186 AN: 249990 AF XY: 0.000539

Gnomad AFR exome AF: 0.00366

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.000199

Gnomad EAS exome AF: 0.000273

Gnomad FIN exome AF: 0.00112

Gnomad NFE exome AF: 0.000734

Gnomad OTH exome AF: 0.00164

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.0000589 AC: 86 AN: 1461274 Hom.: 0 Cov.: 33 AF XY: 0.0000647 AC XY: 47 AN XY: 726940

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

African (AFR) AF: 0.00 AC: 0 AN: 33474

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: 39698

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

European-Finnish (FIN) AF: 0.00126 AC: 67 AN: 52990

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 0.00000719 AC: 8 AN: 1111902

Other (OTH) AF: 0.000149 AC: 9 AN: 60330

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ExAC AF: 0.000478 AC: 58

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

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

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.077
BayesDel_addAF	Benign	-0.082	T
BayesDel_noAF	Benign	-0.36
CADD	Benign	22
DANN	Benign	0.80
DEOGEN2	Uncertain	0.43	T
Eigen	Benign	-0.29
Eigen_PC	Benign	-0.084
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.79	T
M_CAP	Benign	0.055	D
MetaRNN	Benign	0.088	T
MetaSVM	Benign	-0.89	T
MutationAssessor	Benign	1.0	L
PhyloP100		4.4
PrimateAI	Uncertain	0.52	T
PROVEAN	Benign	-0.23	N
REVEL	Benign	0.12
Sift	Benign	0.74	T
Sift4G	Benign	0.33	T
Polyphen		0.0	B
Vest4		0.33
MVP		0.65
MPC		0.49
ClinPred		0.012	T
GERP RS		4.9
Varity_R		0.082
gMVP		0.41
Mutation Taster		=88/12	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: rs759679579; hg19: chr18-48584519;