NM_000038.6:c.1409-1G>T

Variant names:

• chr5-112827107-G-T
• rs863225313
• NM_000038.6:c.1409-1G>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1_Moderate PM2 PP5_Very_Strong

The NM_000038.6(APC):​c.1409-1G>T variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 10.0
• Publications: 3 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

ENSG00000258864 (HGNC:):

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.016408814 fraction of the gene. Cryptic splice site detected, with MaxEntScore 8.3, offset of -36, new splice context is: accagtttgttttattttAGatg. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 5-112827107-G-T is Pathogenic according to our data. Variant chr5-112827107-G-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 217927.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.1409-1G>T		splice_acceptor intron	N/A	NP_000029.2
	APC	NM_001407446.1		c.1493-1G>T		splice_acceptor intron	N/A	NP_001394375.1
	APC	NM_001354896.2		c.1463-1G>T		splice_acceptor intron	N/A	NP_001341825.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APC	ENST00000257430.9	TSL:5 MANE Select	c.1409-1G>T		splice_acceptor intron	N/A	ENSP00000257430.4
	APC	ENST00000508376.6	TSL:1	c.1409-1G>T		splice_acceptor intron	N/A	ENSP00000427089.2
	APC	ENST00000502371.3	TSL:1	n.1408+5116G>T		intron	N/A	ENSP00000484935.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Pathogenic:2

Jul 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 217927). For these reasons, this variant has been classified as Pathogenic. Studies have shown that disruption of this splice site is associated with altered splicing resulting in multiple RNA products (Invitae). Disruption of this splice site has been observed in individuals with familial adenomatous polyposis (PMID: 950360, 15459959, 19036155, 20685668; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 11 of the APC gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in APC are known to be pathogenic (PMID: 17963004, 20685668).

May 01, 2023

Myriad Genetics, Inc.

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function.

not provided Pathogenic:2

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

Sep 12, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is denoted APC c.1409-1G>T or IVS11-1G>T and consists of a G>T nucleotide substitutionat the -1 position of intron 11 of the APC gene. This variant destroys a canonical splice acceptor site and is predicted tocause abnormal gene splicing, leading to either an abnormal message that is subject to nonsense-mediated mRNAdecay or to an abnormal protein product. This variant has been reported in at least one individual with familialadenomatous polyposis (Lagarde 2010). Based on the current evidence, we consider this variant to be pathogenic

Hereditary cancer-predisposing syndrome Pathogenic:1

Jul 18, 2017

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1409-1G>T intronic pathogenic mutation results from a G to T substitution one nucleotide upstream from coding exon 11 of the APC gene. This alteration was identified in 1/863 French patients with FAP. (Lagarde A et al. J. Med. Genet., 2010 Oct;47:721-2). Another alteration at this same nucleotide positiion, c.1409-1G>A, has been reported in multiple FAP families, and it has been shown to create a new acceptor splice site one base pair downstream with a lower splicing efficiency but no indication of exon skipping (Wallis YL et al. J Med Genet. 1999 Jan;36(1):14-20; Aretz S et al. Hum Mutat. 2004 Nov;24(5):370-80). In addition to the information presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	36
DANN	Uncertain	1.0
Eigen	Pathogenic	1.3
Eigen_PC	Pathogenic	1.2
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		10
GERP RS		5.8
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.96		Position offset: 12
DS_AL_spliceai		1.0		Position offset: 1

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

Other links and lift over

dbSNP: rs863225313; hg19: chr5-112162804;