chr5-112827187-A-T
Variant summary
Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_StrongBP6_Very_StrongBP7BS1
The NM_000038.6(APC):c.1488A>T(p.Thr496Thr) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000111 in 1,613,964 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. T496T) has been classified as Likely benign.
Frequency
Consequence
NM_000038.6 synonymous
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: Benign. The variant received -17 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes  0.000230  AC: 35AN: 152222Hom.:  0  Cov.: 33 show subpopulations 
GnomAD2 exomes  AF:  0.000474  AC: 119AN: 251268 AF XY:  0.000493   show subpopulations 
GnomAD4 exome  AF:  0.0000985  AC: 144AN: 1461624Hom.:  1  Cov.: 33 AF XY:  0.000100  AC XY: 73AN XY: 727118 show subpopulations 
Age Distribution
GnomAD4 genome  0.000230  AC: 35AN: 152340Hom.:  0  Cov.: 33 AF XY:  0.000309  AC XY: 23AN XY: 74494 show subpopulations 
Age Distribution
ClinVar
Submissions by phenotype
not provided    Benign:5 
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Variant summary: The APC c.1488A>T (p.Thr496Thr) variant involves the alteration of a non-conserved nucleotide, resulting in a synonymous change. One in silico tool predicts a damaging outcome for this variant. 5/5 splice prediction tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. This variant was found in 55/121488 control chromosomes, predominantly observed in the East Asian subpopulation at a frequency of 0.006028 (52/8626). This frequency is about 84 times the estimated maximal expected allele frequency of a pathogenic APC variant (0.0000714), suggesting this is likely a benign polymorphism found primarily in the populations of East Asian origin. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as likely benign/benign. Taken together, this variant is classified as benign. -
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Hereditary cancer-predisposing syndrome    Benign:3 
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. -
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not specified    Benign:2 
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Familial adenomatous polyposis 1    Benign:2 
This variant is considered benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -
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APC-Associated Polyposis Disorders    Benign:1 
This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -
Carcinoma of colon    Benign:1 
The APC p.Thr496= variant was identified in 1 of 338 proband chromosomes (frequency: 0.01) from individuals or families with colorectal cancer, and was not identified in 244 control chromosomes from healthy individuals (Chang 2016, Chen 2006). The variant was also identified in dbSNP (ID: rs9282599) as “With Likely benign allele”, ClinVar (classified as benign by Invitae, Color Genomics and Integrated Genetics/Laboratory Corporation of America; as likely benign by Ambry Genetics and Quest Diagnostics Nichols Institute San Juan Capistrano), Clinvitae, LOVD 3.0 (Probably does not affect function), or Zhejiang Colon Cancer Database (2X). The variant was not identified in GeneInsight-COGR, Cosmic, or UMD-LSDB databases. The variant was identified in control databases in 123 of 277014 chromosomes (1 homozygous) at a frequency of 0.0004 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include East Asian in 122 of 18852 chromosomes (freq: 0.01), Finnish in 1 of 25786 chromosomes (freq: 0.00004), while the variant was not observed in the African, Other, Latino, European, Ashkenazi Jewish, and South Asian populations. The p.Thr496= variant is not expected to have clinical significance because it does not result in a change of amino acid and is not located in a known consensus splice site. In addition, 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 this variant meets our laboratory's criteria to be classified as benign. -
APC-related disorder    Benign:1 
This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Computational scores
Source: 
Splicing
 Find out detailed SpliceAI scores and Pangolin per-transcript scores at