rs144378484

Positions:

• chr18-51058404-A-G
• chr18-51058404-A-T

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS2

The NM_005359.6(SMAD4):​c.852A>G​(p.Gln284Gln) variant causes a synonymous change. The variant allele was found at a frequency of 0.0000638 in 1,613,800 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).

• Frequency:
  • Genomes: 𝑓 0.000079 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000062 (0 hom.)
• Consequence: SMAD4 NM_005359.6 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:13 O:1
• Conservation: PhyloP100: 4.02

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 (HGNC:):

ACMG classification

Verdict is Benign. Variant got -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.51).
• BP6: Variant 18-51058404-A-G is Benign according to our data. Variant chr18-51058404-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 183751.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=11, Uncertain_significance=1, not_provided=1, Benign=2}.
• BS2: High AC in GnomAd4 at 12 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMAD4	NM_005359.6	c.852A>G	p.Gln284Gln	synonymous_variant	7/12	ENST00000342988.8	NP_005350.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMAD4	ENST00000342988.8	c.852A>G	p.Gln284Gln	synonymous_variant	7/12	5	NM_005359.6	ENSP00000341551.3

Frequencies

GnomAD3 genomes AF: 0.0000790 AC: 12 AN: 151912 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000483

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: 0.000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000517 AC: 13 AN: 251480 Hom.: 0 AF XY: 0.0000441 AC XY: 6 AN XY: 135914

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000114

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000622 AC: 91 AN: 1461888 Hom.: 0 Cov.: 33 AF XY: 0.0000605 AC XY: 44 AN XY: 727246

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000782

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.0000790 AC: 12 AN: 151912 Hom.: 0 Cov.: 32 AF XY: 0.0000674 AC XY: 5 AN XY: 74190

Gnomad4 AFR AF: 0.0000483

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000115 Hom.: 0

Bravo AF: 0.0000718

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:13 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome Benign:3

Likely benign, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Dec 13, 2023	- -
Benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Apr 10, 2023	This variant is considered benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -
Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 28, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

not specified Uncertain:1 Benign:1

Benign, criteria provided, single submitter	clinical testing	GeneDx	May 05, 2015	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital	Aug 15, 2023	- -

not provided Benign:2

Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Oct 01, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Oct 06, 2016	Variant summary: The SMAD4 c.852A>G (p.Gln284Gln) variant causes a synonymous change involving a conserved nucleotide with 4/5 splice prediction tools predicting an impact on splicing and ESE finder predicts that this variant may affect ESE binding, although these predictions have yet to be functionally assessed. The variant of interest was observed in the large, broad control population, ExAC, with an allele frequency of 5/121408 (1/24283), predominantly in the European (Non-Finnish) cohort, 5/66740 (1/13347), which does exceed the estimated maximal expected allele frequency for a pathogenic SMAD4 variant of 1/500000. Therefore, suggesting the variant could be a common polymorphism found in population(s) of European (Non-Finnish) origin, however, this observation needs to be cautiously considered due to presence of a pseudogene possibly being captured. The variant of interest has not, to our knowledge, been reported in affected individuals via publications. However, clinical diagnostic laboratories have cited the variant with conflicting classifications "likely benign" or "uncertain significance." Therefore, the variant of interest has been classified as "Likely Benign," until additional information becomes available (ie, clinical and/or functional studies). -

Generalized juvenile polyposis/juvenile polyposis coli Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Counsyl	Dec 23, 2015	- -
Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 28, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Hereditary cancer-predisposing syndrome Benign:2

Likely benign, criteria provided, single submitter	curation	Sema4, Sema4	Nov 12, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jun 06, 2016	- -

Myhre syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Apr 28, 2017

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases allowed determination this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 26, 2024

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Juvenile polyposis syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 31, 2024

- -

Hereditary hemorrhagic telangiectasia;C1868081:Generalized juvenile polyposis/juvenile polyposis coli Other:1

not provided, no classification provided

phenotyping only

GenomeConnect - Invitae Patient Insights Network

-

Variant classified as Likely benign and reported on 06-13-2019 by Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.51
CADD	Benign	12
DANN	Benign	0.59
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

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

Publications

LitVar

Other links and lift over

dbSNP: rs144378484; hg19: chr18-48584774;