rs1114167603
Variant summary
Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM5_SupportingPM2_SupportingPS4_Supporting
This summary comes from the ClinGen Evidence Repository: The c.3077A>C variant in APC is a missense variant predicted to cause the substitution of asparagine by threonine at amino acid position 1026 (p.Asn1026Thr). This variant has been reported in 3 probands with FAP worth 1.5 phenotype points (PS4_Supporting; Ambry Internal Data). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). Another missense variant, c.3077A>G (p.Asn1026Ser) in the same codon has been classified as Likely Pathogenic for FAP by the ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (HCCP VCEP) (PM5_Supporting; PMID 18166348). In summary, due to insufficient evidence, this variant is a Variant of Uncertain Significance for FAP based on the ACMG/AMP criteria applied, as specified by the HCCP VCEP: PS4_Supporting, PM2_Supporting, and PM5_Supporting (VCEP specifications version 1; date of approval: 12/12/2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA16028070/MONDO:0021056/089
Frequency
Consequence
NM_000038.6 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 3 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
APC | ENST00000257430.9 | c.3077A>C | p.Asn1026Thr | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
ENSG00000258864 | ENST00000520401.1 | n.228+9699A>C | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 |
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome Cov.: 33
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
Familial adenomatous polyposis 1 Uncertain:2
The c.3077A>C variant in APC is a missense variant predicted to cause the substitution of asparagine by threonine at amino acid position 1026 (p.Asn1026Thr). This variant has been reported in 3 probands with FAP worth 1.5 phenotype points (PS4_Supporting; Ambry Internal Data). This variant is absent from gnomAD v2.1.1 (PM2_Supporting). Another missense variant, c.3077A>G (p.Asn1026Ser) in the same codon has been classified as Likely Pathogenic for FAP by the ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (HCCP VCEP) (PM5_Supporting; PMID 18166348). In summary, due to insufficient evidence, this variant is a Variant of Uncertain Significance for FAP based on the ACMG/AMP criteria applied, as specified by the HCCP VCEP: PS4_Supporting, PM2_Supporting, and PM5_Supporting (VCEP specifications version 1; date of approval: 12/12/2022). -
This sequence change replaces asparagine, which is neutral and polar, with threonine, which is neutral and polar, at codon 1026 of the APC protein (p.Asn1026Thr). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with APC-related conditions. ClinVar contains an entry for this variant (Variation ID: 428167). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is not expected to disrupt APC protein function with a negative predictive value of 95%. This variant disrupts the p.Asn1026 amino acid residue in APC. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 18166348). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Hereditary cancer-predisposing syndrome Pathogenic:1
The p.N1026T variant (also known as c.3077A>C), located in coding exon 15 of the APC gene, results from an A to C substitution at nucleotide position 3077. The asparagine at codon 1026 is replaced by threonine, an amino acid with similar properties. While this exact alteration has not been reported in the literature to our knowledge, a similar alteration at this same location, p.N1026S (c.3077A>G), has been reported to segregate with disease in a large Spanish attenuated FAP family (Menéndez M et al. Gastroenterology 2008 Jan; 134(1):56-64). Menéndez M et al. further investigated the functional significance of the p.N1026S alteration using an in vitro beta-catenin binding assay and showed it resulted in a functionally altered protein. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
not specified Uncertain:1
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Carcinoma of colon Uncertain:1
The APC p.Asn1026Thr was not identified in the literature, dbSNP, 1000 Genomes Project, NHLBI GO Exome Sequencing Project (ESP, the Exome Aggregation Consortium (ExAC) database (released Jan 13, 2015), Clinvitae database, COSMIC, Zhejiang Colon Cancer Database (LOVD), ClinVar database, GeneInsight - COGR database, the InSiGHT Colon Cancer Gene Variant Database (LOVD) and UMD. A variant at the same loci, p.Asn1026Ser was identified in the literature and classified as pathogenic based on segregation data and in vivo studies (Menendez 2008). The p.Asn1026 residue is conserved across mammals and other organisms, and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein and this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and 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. This variant is classified as a variant of uncertain significance. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at