5-112775693-C-T
Variant summary
Our verdict is Pathogenic. The variant received 19 ACMG points: 19P and 0B. PVS1PM2PP3PP5_Very_Strong
The NM_000038.6(APC):c.487C>T(p.Gln163*) variant causes a stop gained change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000688 in 1,453,850 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Q163Q) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.
Frequency
Consequence
NM_000038.6 stop_gained
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: Pathogenic. The variant received 19 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes Cov.: 32
GnomAD4 exome AF: 6.88e-7 AC: 1AN: 1453850Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1AN XY: 722932 show subpopulations
Age Distribution
GnomAD4 genome Cov.: 32
ClinVar
Submissions by phenotype
not provided Pathogenic:2Uncertain:1
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Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); This variant is associated with the following publications: (PMID: 18829530, 25525159, 11960572, 16461775, 28199314, 9585611, 15300853, 18782851, 23159591, 11247895, 20685668, 17963004) -
Familial adenomatous polyposis 1 Pathogenic:2
This variant is considered pathogenic. This variant creates a termination codon and is predicted to result in premature protein truncation. -
For these reasons, this variant has been classified as Pathogenic. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. ClinVar contains an entry for this variant (Variation ID: 217991). This premature translational stop signal has been observed in individual(s) with colonic adenomas and colorectal cancer (PMID: 9585611). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Gln163*) in the APC gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in APC are known to be pathogenic (PMID: 17963004, 20685668). -
Hereditary cancer-predisposing syndrome Pathogenic:2
This variant changes 1 nucleotide in exon 5 of the APC gene, creating a premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in individuals and families affected with familial adenomatous polyposis (FAP) and attenuated familial adenomatous polyposis (AFAP)(PMID: 9585611, 11247895, 16461775, 19701947, 33134403). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of APC function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -
The p.Q163* pathogenic mutation (also known as c.487C>T), located in exon 4 of the APC gene, results from a C to T substitution at nucleotide position 487. This changes the amino acid from a glutamine to a stop codon within exon 4. This variant has been reported in multiple individuals with features consistent with APC-associated polyposis conditions (Abrams HR et al. ACG Case Rep J. 2020 Oct;7(10):e00469; Ambry internal data). This mutation was also identified in six members of a family with hereditary predisposition to colonic adenomas and colorectal cancer. Two family members were diagnosed with colorectal cancer, one at the age of 35 and one at age 60, and four family members were found to have numerous adenomatous colon polyps (Soravia et al. Am. J. Hum. Genet. 1998;62:1290-1301). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, this alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -
Familial multiple polyposis syndrome Pathogenic:1
Variant summary: APC c.487C>T (p.Gln163X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory. The variant was absent in 245984 control chromosomes. c.487C>T has been reported in the literature in multiple individuals affected with Familial Adenomatous Polyposis (example, Scott_2001, Soravia_1998, Sieber_2006). These data indicate that the variant is very likely to be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at