rs767457050
Variant summary
Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_000038.6(APC):c.776G>A(p.Arg259Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000167 in 1,612,944 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. 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. R259W) has been classified as Uncertain significance.
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: Likely_benign. The variant received -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000394 AC: 6AN: 152144Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000159 AC: 4AN: 251060 AF XY: 0.0000295 show subpopulations
GnomAD4 exome AF: 0.0000144 AC: 21AN: 1460800Hom.: 0 Cov.: 30 AF XY: 0.0000234 AC XY: 17AN XY: 726700 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000394 AC: 6AN: 152144Hom.: 0 Cov.: 32 AF XY: 0.0000269 AC XY: 2AN XY: 74332 show subpopulations
ClinVar
Submissions by phenotype
not provided Uncertain:2
Variant summary: The APC c.776G>A (p.Arg259Gln) variant involves the alteration of a conserved nucleotide. 4/4 in silico tools predict a benign outcome for this variant (SNPsandGO not captured due to low reliability index). This variant was found in 2/120040 control chromosomes at a frequency of 0.0000167, which does not exceed the estimated maximal expected allele frequency of a pathogenic APC variant (0.0000714). One clinical diagnostic laboratory/reputable database classified this variant as uncertain significance. The variant of interest has not, to our knowledge, been reported in affected individuals via publications nor evaluated for functional impact by in vivo/vitro studies. Because of the absence of clinical information and the lack of functional studies, the variant is classified as a variant of uncertain significance (VUS) until additional information becomes available. -
Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Not observed in any cases, but was observed in unaffected controls from a colorectal and breast cancer study (PMID: 32658311); This variant is associated with the following publications: (PMID: 30458888, 28526081, 32658311) -
Hereditary cancer-predisposing syndrome Uncertain:1Benign:1
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The p.R259Q variant (also known as c.776G>A), located in coding exon 7 of the APC gene, results from a G to A substitution at nucleotide position 776. The arginine at codon 259 is replaced by glutamine, an amino acid with highly similar properties. Missense alterations in APC are not a common cause of disease (Spier I et al. Genet Med. 2024 Feb;26(2):100992). This amino acid position is well conserved in available vertebrate species; however, glutamine is the reference amino acid in other vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Based on the available evidence, the clinical significance of this variant remains unclear. -
not specified Uncertain:1
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Gastric cancer;C0346629:Colorectal cancer;C1851124:Desmoid disease, hereditary;C2239176:Hepatocellular carcinoma;C2713442:Familial adenomatous polyposis 1;C4749917:Gastric adenocarcinoma and proximal polyposis of the stomach Uncertain:1
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Familial adenomatous polyposis 1 Uncertain:1
This sequence change replaces arginine, which is basic and polar, with glutamine, which is neutral and polar, at codon 259 of the APC protein (p.Arg259Gln). This variant is present in population databases (rs767457050, gnomAD 0.003%). 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: 411335). 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%. 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. -
Classic or attenuated familial adenomatous polyposis Uncertain:1
This missense variant replaces arginine with glutamine at codon 259 of the APC protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual affected with pancreatic cancer (PMID: 30458888). This variant has been identified in 4/251060 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. -
APC-related disorder Uncertain:1
The APC c.776G>A variant is predicted to result in the amino acid substitution p.Arg259Gln. This variant was found in a control individual in a study of Turkish breast cancer and colorectal cancer patients (Akcay et al. 2020. PubMed ID: 32658311). This variant is reported in 0.0033% of alleles in individuals of South Asian descent in gnomAD. In ClinVar, it is reported as uncertain significance (https://www.ncbi.nlm.nih.gov/clinvar/variation/411335/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at