5-112840072-C-T
Variant summary
Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.
The NM_000038.6(APC):c.4478C>T(p.Thr1493Met) variant causes a missense change. The variant allele was found at a frequency of 0.000031 in 1,613,948 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. T1493I) 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: Uncertain_significance. The variant received 0 ACMG points.
Transcripts
RefSeq
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt | 
|---|---|---|---|---|---|---|---|---|---|---|
| APC | ENST00000257430.9 | c.4478C>T | p.Thr1493Met | missense_variant | Exon 16 of 16 | 5 | NM_000038.6 | ENSP00000257430.4 | ||
| ENSG00000258864 | ENST00000520401.1 | n.228+11100C>T | intron_variant | Intron 3 of 7 | 3 | ENSP00000454861.1 | 
Frequencies
GnomAD3 genomes  0.0000526  AC: 8AN: 152150Hom.:  0  Cov.: 32 show subpopulations 
GnomAD2 exomes  AF:  0.0000240  AC: 6AN: 250452 AF XY:  0.0000295   show subpopulations 
GnomAD4 exome  AF:  0.0000287  AC: 42AN: 1461798Hom.:  0  Cov.: 33 AF XY:  0.0000303  AC XY: 22AN XY: 727210 show subpopulations 
Age Distribution
GnomAD4 genome  0.0000526  AC: 8AN: 152150Hom.:  0  Cov.: 32 AF XY:  0.0000269  AC XY: 2AN XY: 74340 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
not provided    Uncertain:4 
The APC c.4478C>T (p.Thr1493Met) variant has been reported in the published literature in in individuals with colorectal cancer (PMID: 28944238 (2017)) as well as in reportedly healthy individuals (PMID: 18199528 (2008)). The frequency of this variant in the general population, 0.00012 (3/24676 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. -
Variant summary: The APC c.4478C>T (p.Thr1493Met) variant involves the alteration of a conserved nucleotide. 4/4 in silico tools predict a damaging outcome for this variant. This variant was found in 5/123012 control chromosomes at a frequency of 0.0000406, which does not exceed the estimated maximal expected allele frequency of a pathogenic APC variant (0.0000714). The variant was detected in one breast tumor sample and in a control individual in the literature. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as uncertain significance. Taken together, this variant is classified as VUS until additional evidence becomes available. -
In silico analysis supports that this missense variant does not alter protein structure/function; Observed in individual(s) with colorectal cancer, but also in unaffected controls (Azzopardi et al., 2008; DeRycke et al., 2017); This variant is associated with the following publications: (PMID: 26486734, 18199528, 28944238, 35709138) -
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Hereditary cancer-predisposing syndrome    Uncertain:2Benign:2 
This alteration is classified as 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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Familial adenomatous polyposis 1    Uncertain:3 
This sequence change replaces threonine, which is neutral and polar, with methionine, which is neutral and non-polar, at codon 1493 of the APC protein (p.Thr1493Met). This variant is present in population databases (rs374892194, gnomAD 0.01%). 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: 141521). 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. -
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
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Classic or attenuated familial adenomatous polyposis    Uncertain:1 
This missense variant replaces threonine with methionine at codon 1493 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 a healthy control individual (PMID 18199528) and in a tumor sample from an individual affected with breast cancer (PMID: 26486734). This variant has been identified in 8/281844 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