5-112801326-G-T
Variant summary
Our verdict is Benign. Variant got -8 ACMG points: 0P and 8B. BP4_ModerateBP6BP7BS2
The NM_000038.6(APC):c.777G>T(p.Arg259Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000162 in 1,612,850 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_000038.6 synonymous
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -8 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.000171 AC: 26AN: 152164Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.000283 AC: 71AN: 251074Hom.: 0 AF XY: 0.000265 AC XY: 36AN XY: 135664
GnomAD4 exome AF: 0.000161 AC: 235AN: 1460686Hom.: 1 Cov.: 30 AF XY: 0.000169 AC XY: 123AN XY: 726634
GnomAD4 genome AF: 0.000171 AC: 26AN: 152164Hom.: 0 Cov.: 32 AF XY: 0.000175 AC XY: 13AN XY: 74334
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Benign:4
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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. -
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not specified Benign:3
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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. -
Variant summary: APC c.777G>T alters a conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The observed variant frequency within Ashkenazi Jewish control individuals in the gnomAD database is approximately 77 fold of the estimated maximal expected allele frequency for a pathogenic variant in APC causing Familial Adenomatous Polyposis phenotype (7.1e-05), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Ashkenazi Jewish origin. The variant, c.777G>T, has been reported in the literature in one individual affected with Familial Adenomatous Polyposis (Kerr 2013). This report does not provide unequivocal conclusions about association of the variant with Familial Adenomatous Polyposis. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -
Familial adenomatous polyposis 1 Benign:2
This variant is considered benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -
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not provided Benign:2
APC: BP4, BP7 -
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APC-Associated Polyposis Disorders Uncertain:1
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 did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Carcinoma of colon Benign:1
The APC p.Arg259= variant was identified in 1 of 3182 proband chromosomes (frequency: 0.0003) from individuals or families with FAP (Kerr 2013). The variant was also identified in dbSNP (ID: rs147704593) as With other allele, ClinVar (classified as benign by Invitae, GeneDx; classified as likely benign by Ambry Genetics, Color Genomics and two clinical laboratories), GeneInsight-COGR, and LOVD 3.0 databases. The variant was not identified in UMD-LSDB database or Zhejiang Colon Cancer Database. The variant was identified in control databases in 65 of 245844 chromosomes at a frequency of 0.0003 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include Other in 4 of 5476 chromosomes (freq: 0.000731), Latino in 1 of 33516 chromosomes (freq: 0.00003), European Non-Finnish in 6 of 111470 chromosomes (freq: 0.000054), Ashkenazi Jewish in 54 of 9836 chromosomes (freq: 0.00549), while the variant was not observed in the African, East Asian, European Finnish, and South Asian populations. The p.Arg259= variant is not expected to have clinical significance because it does not result in a change of amino acid and is not located in a known consensus splice site. In addition, in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) do not predict a difference in splicing. In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -
Classic or attenuated familial adenomatous polyposis Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at