NM_000038.6:c.4945A>G
Variant summary
Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4
The NM_000038.6(APC):c.4945A>G(p.Ile1649Val) variant causes a missense change. The variant allele was found at a frequency of 0.00000372 in 1,614,036 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I1649M) 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 -1 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
APC | ENST00000257430.9 | c.4945A>G | p.Ile1649Val | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
ENSG00000258864 | ENST00000520401.1 | n.228+11567A>G | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152176Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.00000398 AC: 1AN: 250994 AF XY: 0.00000737 show subpopulations
GnomAD4 exome AF: 0.00000342 AC: 5AN: 1461860Hom.: 0 Cov.: 65 AF XY: 0.00000138 AC XY: 1AN XY: 727236 show subpopulations
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152176Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1AN XY: 74346 show subpopulations
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:3
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This missense variant replaces isoleucine with valine at codon 1649 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 been reported in individuals affected with colorectal cancer (PMID: 32658311, 34271781) and in one control individual (PMID: 14999774). This variant has been identified in 1/250994 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. -
The p.I1649V variant (also known as c.4945A>G), located in coding exon 15 of the APC gene, results from an A to G substitution at nucleotide position 4945. The isoleucine at codon 1649 is replaced by valine, an amino acid with highly similar properties. This alteration was detected along with the APC p.A1002G variant in a 42-year-old control subject with a reported colonoscopy negative for polyps (Gismondi V et al. Int J Cancer. 2004 May;109:680-4). This alteration was seen in 0/732 breast cancer patients, 1/189 colorectal cancer patients and 0/490 cancer-free elderly controls in a Turkish population (Akcay IM et al. Int J Cancer. 2021 01;148:285-295). This variant was reported in individual(s) with features consistent with APC-related familial adenomatous polyposis in at least one individual (Ambry internal data). This amino acid position is well conserved in available vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Familial adenomatous polyposis 1 Uncertain:2
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This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 1649 of the APC protein (p.Ile1649Val). This variant is present in population databases (rs772273122, gnomAD 0.0009%). This missense change has been observed in individual(s) with colorectal cancer (PMID: 34271781). ClinVar contains an entry for this variant (Variation ID: 537531). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae 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. -
Gastric cancer;C1851124:Desmoid disease, hereditary;C2713442:Familial adenomatous polyposis 1 Uncertain:1
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Classic or attenuated familial adenomatous polyposis Uncertain:1
This missense variant replaces isoleucine with valine at codon 1649 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). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with hereditary cancer, but has been reported in one control subject (PMID 14999774) in the literature. This variant has been identified in 1/250994 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. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at