5-112840359-C-T
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM1BP6
The NM_000038.6(APC):c.4765C>T(p.Arg1589Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000044 in 1,614,028 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R1589G) has been classified as Likely benign.
Frequency
Consequence
NM_000038.6 missense
Scores
Clinical Significance
Conservation
Publications
- classic or attenuated familial adenomatous polyposisInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- desmoid tumorInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
- familial adenomatous polyposis 1Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
- gastric adenocarcinoma and proximal polyposis of the stomachInheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
- sarcomaInheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- APC-related attenuated familial adenomatous polyposisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Turcot syndrome with polyposisInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- Cenani-Lenz syndactyly syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| APC | ENST00000257430.9 | c.4765C>T | p.Arg1589Cys | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
| ENSG00000258864 | ENST00000520401.1 | n.228+11387C>T | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 |
Frequencies
GnomAD3 genomes AF: 0.0000329 AC: 5AN: 152156Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000757 AC: 19AN: 251116 AF XY: 0.0000663 show subpopulations
GnomAD4 exome AF: 0.0000451 AC: 66AN: 1461872Hom.: 0 Cov.: 66 AF XY: 0.0000440 AC XY: 32AN XY: 727244 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000329 AC: 5AN: 152156Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74316 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not specified Uncertain:1Benign:2
DNA sequence analysis of the APC gene demonstrated a sequence change, c.4765C>T, in exon 16 that results in an amino acid change, p.Arg1589Cys. This sequence change has been described in the gnomAD database with a frequency of 0.01%in the African/African American subpopulation (dbSNP rs72541813). The p.Arg1589Cys change affects a moderately conserved amino acid residue located in a domain of the APC protein that is known to be functional. In-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL) provide contradictory results for the p.Arg1589Cys substitution. This sequence change does not appear to have been previously described in individuals with APC-related disorders. Due to insufficient evidences and the lack of functional studies, the clinical significance of the p.Arg1589Cys change remains unknown at this time. -
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Variant summary: APC c.4765C>T (p.Arg1589Cys) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 7.6e-05 in 251116 control chromosomes, predominantly at a frequency of 0.00011 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 1.5 fold of the estimated maximal expected allele frequency for a pathogenic variant in APC causing Familial Adenomatous Polyposis phenotype (7.1e-05), suggesting that the variant is a benign polymorphism. In a case-control study, the variant was absent in 691 unrelated North American patients with colorectal adenomas, but was found in 969 matched healthy controls (Azzopardi_2008). In addition, the variant, c.4765C>T, has been reported in the literature as a germline variant in an individual affected with melanocytic nevi (Pawlikowski_2015), and was found in a suspected premalignant pancreatic lesion and in tumor samples (melanoma, gastric carcinoma), however it was unclear if it occurred as a germline or somatic alteration (Garman_2017, Plougmann_2020, Sa_2020). These reports do 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. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, and classified the variant as VUS (n=2) or likely benign (n=2). Based on the evidence outlined above, the variant was classified as likely benign. -
not provided Uncertain:2
The APC c.4765C>T (p.Arg1589Cys) variant has been reported in the published literature in an individual with prostate cancer (PMID: 35534218 (2022)). This variant has also been identified in reportedly healthy individuals (PMID: 18199528 (2008)). The frequency of this variant in the general population, 0.00012 (3/24938 chromosomes in African/African American subpopulation (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is higher than would generally be expected for pathogenic variants in this gene. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 18199528, 26178707, 31552911, 32070411, 25815427, 35534218) -
Hereditary cancer-predisposing syndrome Uncertain:1Benign:1
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. -
This missense variant replaces arginine with cysteine at codon 1589 of the APC protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with APC-related disorders in the literature. In a large study of individuals affected with colorectal adenomas, this variant was absent in affected individuals and reported in a healthy control individual (PMID: 18199528). This variant has been identified in 23/282472 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Classic or attenuated familial adenomatous polyposis Uncertain:1
This missense variant replaces arginine with cysteine at codon 1589 of the APC protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with APC-related disorders in the literature. In a large study of individuals affected with colorectal adenomas, this variant was absent in affected individuals and reported in a healthy control individual (PMID: 18199528). This variant has been identified in 23/282472 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Familial adenomatous polyposis 1 Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at