rs377119288
Variant summary
Our verdict is Benign. Variant got -10 ACMG points: 1P and 11B. PP2BP4_ModerateBP6BS1BS2
The NM_005359.6(SMAD4):c.947A>G(p.Asn316Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000434 in 1,611,112 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_005359.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -10 ACMG points.
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
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SMAD4 | NM_005359.6 | c.947A>G | p.Asn316Ser | missense_variant | Exon 8 of 12 | ENST00000342988.8 | NP_005350.1 |
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000394 AC: 6AN: 152130Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000557 AC: 14AN: 251388Hom.: 0 AF XY: 0.0000810 AC XY: 11AN XY: 135870
GnomAD4 exome AF: 0.0000439 AC: 64AN: 1458982Hom.: 2 Cov.: 29 AF XY: 0.0000592 AC XY: 43AN XY: 726098
GnomAD4 genome AF: 0.0000394 AC: 6AN: 152130Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3AN XY: 74296
ClinVar
Submissions by phenotype
not specified Benign:2Other:1
Variant summary: SMAD4 c.947A>G (p.Asn316Ser) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 5.6e-05 in 251388 control chromosomes, predominantly at a frequency of 0.00033 within the South Asian subpopulation in the gnomAD database. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 165 fold of the estimated maximal expected allele frequency for a pathogenic variant in SMAD4 causing Juvenile Polyposis Syndrome phenotype (2e-06), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. c.947A>G has been reported in the literature in individuals who underwent multigene panel testing for a variety of indications. As a representative ascertainment, it was reported as a probably benign variant in a patient with medulloblastoma (e.g., Zhang_2015), as a VUS in patients with polyps/colorectal cancer (e.g., Chang_2017, Buendia_2021, Xu_2020), as a VUS in a patient with pulmonary hypertension (e.g., Yang_2018), as a VUS in a patient with breast and/or ovarian cancer (e.g., Kwong_2020). These reports do not provide unequivocal conclusions about association of the variant with Juvenile Polyposis Syndrome. At-least one recent report of co-occurrences with other pathogenic variants has been described in a 15 year old with an early onset colorectal adenocarcinoma who harbored pathogenic germline variants in both the APC and the MLH1 gene (APC c.3329C>A, p.Ser110*; MLH1 c.156del, p.Glu53Argfs*4, Buendia_2021), providing supporting evidence for a benign role. The APC variant was reported as a spontaneous mutation whereas the MLH1 and this SMAD4 variants were both maternally derived. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 26580448, 32068069, 33745841, 29069792, 29743074, 32973888). ClinVar contains an entry for this variant (Variation ID: 135245). Based on the evidence outlined above, the variant was classified as likely benign. -
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not provided Uncertain:2
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In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 31856217, 32068069, 24728327, 28199989, 29069792, 29743074, 32973888, 33745841, 35670754, 29212164, 26580448, 10636916, 37966258, 36243179) -
Hereditary cancer-predisposing syndrome Uncertain:1Benign:1
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Familial thoracic aortic aneurysm and aortic dissection Uncertain:1
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Generalized juvenile polyposis/juvenile polyposis coli Uncertain:1
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Juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome Uncertain:1
This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -
Hereditary cancer-predisposing syndrome;C4707243:Familial thoracic aortic aneurysm and aortic dissection Benign:1
This alteration is classified as 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
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at