NM_000038.6:c.74_75delAA

Variant names:

• chr5-112754963-CAA-C
• rs1554067124
• NM_000038.6:c.74_75delAA

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000038.6(APC):​c.74_75delAA​(p.Gln25ArgfsTer5) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. Q25Q) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.81
• Publications: 0 publications found

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

ACMG classification

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

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 2320 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 5-112754963-CAA-C is Pathogenic according to our data. Variant chr5-112754963-CAA-C is described in ClinVar as Pathogenic. ClinVar VariationId is 470090.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000038.6. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APC	NM_000038.6	MANE Select	c.74_75delAA	p.Gln25ArgfsTer5	frameshift	Exon 2 of 16	NP_000029.2
	APC	NM_001354896.2		c.74_75delAA	p.Gln25ArgfsTer5	frameshift	Exon 2 of 17	NP_001341825.1
	APC	NM_001407447.1		c.74_75delAA	p.Gln25ArgfsTer5	frameshift	Exon 2 of 17	NP_001394376.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APC	ENST00000257430.9	TSL:5 MANE Select	c.74_75delAA	p.Gln25ArgfsTer5	frameshift	Exon 2 of 16	ENSP00000257430.4
	APC	ENST00000508376.6	TSL:1	c.74_75delAA	p.Gln25ArgfsTer5	frameshift	Exon 3 of 17	ENSP00000427089.2
	APC	ENST00000502371.3	TSL:1	n.74_75delAA		non_coding_transcript_exon	Exon 1 of 12	ENSP00000484935.2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Pathogenic:2

Dec 26, 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.Gln25Argfs*5) 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: 23159591). ClinVar contains an entry for this variant (Variation ID: 470090). For these reasons, this variant has been classified as Pathogenic.

Apr 24, 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.

Gastric cancer;C0346629:Colorectal cancer;C1851124:Desmoid disease, hereditary;C2239176:Hepatocellular carcinoma;C2713442:Familial adenomatous polyposis 1;C4749917:Gastric adenocarcinoma and proximal polyposis of the stomach Pathogenic:1

Apr 13, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:1

May 12, 2025

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); Identified in a patient with a clinical presentation suggestive of FAP in published literature and in a patient with FAP referred for genetic testing at GeneDx (PMID: 23159591); This variant is associated with the following publications: (PMID: 23159591)

Hereditary cancer-predisposing syndrome Pathogenic:1

Aug 08, 2025

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.74_75delAA pathogenic mutation, located in coding exon 1 of the APC gene, results from a deletion of two nucleotides at nucleotide positions 74 to 75, causing a translational frameshift with a predicted alternate stop codon (p.Q25Rfs*5). Premature termination codons are typically deleterious in nature. In a large (n=1,591) series of patients referred for APC testing, this alteration was detected in one individual. (Kerr SE et al. J Mol Diagn, 2013 Jan;15:31-43). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). As such, this alteration is classified as a disease-causing mutation. However, alterations that result in premature termination in coding exon 1 are associated with an attenuated phenotype and may have reduced penetrance compared to classic familial adenomatous polyposis syndrome. Clinical correlation is advised.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.8
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

Other links and lift over

dbSNP: rs1554067124; hg19: chr5-112090660;