chr5-112815553-ACT-A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1PM2PP5_Very_Strong

The NM_000038.6(APC):​c.896_897delCT​(p.Ser299CysfsTer27) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000685 in 1,460,126 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. S299S) has been classified as Benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

APC
NM_000038.6 frameshift

Scores

Not classified

Clinical Significance

Pathogenic criteria provided, multiple submitters, no conflicts P:7

Conservation

PhyloP100: 4.96

Publications

2 publications found
Variant links:
Genes affected
APC (HGNC:583): (APC regulator of WNT signaling pathway) This gene encodes a tumor suppressor protein that acts as an antagonist of the Wnt signaling pathway. It is also involved in other processes including cell migration and adhesion, transcriptional activation, and apoptosis. Defects in this gene cause familial adenomatous polyposis (FAP), an autosomal dominant pre-malignant disease that usually progresses to malignancy. Mutations in the APC gene have been found to occur in most colorectal cancers, where disease-associated mutations tend to be clustered in a small region designated the mutation cluster region (MCR) and result in a truncated protein product. [provided by RefSeq, Jun 2022]
APC Gene-Disease associations (from GenCC):
  • classic or attenuated familial adenomatous polyposis
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • desmoid tumor
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, Genomics England PanelApp
  • familial adenomatous polyposis 1
    Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
  • gastric adenocarcinoma and proximal polyposis of the stomach
    Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
  • sarcoma
    Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
  • APC-related attenuated familial adenomatous polyposis
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Turcot syndrome with polyposis
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • Cenani-Lenz syndactyly syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 18 ACMG points.

PVS1
Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 5-112815553-ACT-A is Pathogenic according to our data. Variant chr5-112815553-ACT-A is described in ClinVar as Pathogenic. ClinVar VariationId is 42251.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
APCNM_000038.6 linkc.896_897delCT p.Ser299CysfsTer27 frameshift_variant Exon 9 of 16 ENST00000257430.9 NP_000029.2 P25054-1Q4LE70

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
APCENST00000257430.9 linkc.896_897delCT p.Ser299CysfsTer27 frameshift_variant Exon 9 of 16 5 NM_000038.6 ENSP00000257430.4 P25054-1

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
6.85e-7
AC:
1
AN:
1460126
Hom.:
0
AF XY:
0.00000138
AC XY:
1
AN XY:
726436
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33418
American (AMR)
AF:
0.00
AC:
0
AN:
44662
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26072
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39616
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86234
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53270
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5752
European-Non Finnish (NFE)
AF:
9.00e-7
AC:
1
AN:
1110852
Other (OTH)
AF:
0.00
AC:
0
AN:
60250
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Pathogenic
Submissions summary: Pathogenic:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Familial multiple polyposis syndrome Pathogenic:2
Jan 06, 2025
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: APC c.896_897delCT (p.Ser299CysfsX27) 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. The variant was absent in 251118 control chromosomes. c.896_897delCT has been reported in the literature in multiple individuals affected with Familial Adenomatous Polyposis (example: Cao_2006). These data indicate that the variant is very likely to be associated with disease.The following publication has been ascertained in the context of this evaluation (PMID: 17026565). ClinVar contains an entry for this variant (Variation ID: 42251). Based on the evidence outlined above, the variant was classified as pathogenic. -

Apr 08, 2009
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Pathogenic
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Familial adenomatous polyposis 1 Pathogenic:2
Mar 04, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change creates a premature translational stop signal (p.Ser299Cysfs*27) 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). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with familial adenomatous polyposis (PMID: 8118461, 17604324). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 42251). For these reasons, this variant has been classified as Pathogenic. -

Apr 27, 2023
Myriad Genetics, Inc.
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is considered pathogenic. This variant creates a frameshift predicted to result in premature protein truncation. -

not provided Pathogenic:2
Jul 29, 2024
GeneDx
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Frameshift 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: 8118461, 8187091, 34454113, 17604324) -

Feb 21, 2018
Quest Diagnostics Nichols Institute San Juan Capistrano
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome Pathogenic:1
Jul 13, 2021
Ambry Genetics
Significance:Pathogenic
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The c.896_897delCT pathogenic mutation, located in coding exon 8 of the APC gene, results from a deletion of two nucleotides at nucleotide positions 896 to 897, causing a translational frameshift with a predicted alternate stop codon (p.S299Cfs*27). This mutation has been reported in multiple familial adenomatous polyposis (FAP) families (Koorey DJ et al. Hum. Mutat., 1994;3:12-8; Hes FJ et al. Gut, 2008 Jan;57:71-6; Ambry internal data). 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. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
PhyloP100
5.0
Mutation Taster
=0/200
disease causing (ClinVar)

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.0
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs397515735; hg19: chr5-112151250; COSMIC: COSV57390110; API