5-112837551-A-G

Position:

• chr5-112837551-A-G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000038.6(APC):​c.1959-2A>G 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: Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 8.95

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]

ENSG00000258864 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 5-112837551-A-G is Pathogenic according to our data. Variant chr5-112837551-A-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 229816.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr5-112837551-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APC	NM_000038.6	c.1959-2A>G		splice_acceptor_variant, intron_variant		ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.1959-2A>G		splice_acceptor_variant, intron_variant		5	NM_000038.6	ENSP00000257430.4
ENSG00000258864	ENST00000520401.1	n.228+8579A>G		intron_variant		3		ENSP00000454861.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	May 03, 2023	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. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	May 06, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Mar 28, 2023	In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that disruption of this splice site results in the activation of a cryptic splice site in 16 (Invitae). ClinVar contains an entry for this variant (Variation ID: 229816). Disruption of this splice site has been observed in individuals with familial adenomatous polyposis and attenuated familial adenomatous polyposis (PMID: 15459959, 20685668; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change affects an acceptor splice site in intron 15 of the APC gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in the loss of 4 amino acid residue(s), but is expected to preserve the integrity of the reading-frame. -

Carcinoma of colon Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

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Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 29, 2014

The c.1959-2A>G intronic variant results from an A to G substitution two nucleotides upstream from coding exon 15 in the APC gene. This alteration was reported in an individual with an attenuated FAP phenotype and was demonstrated to result in use of a cryptic splice acceptor site, causing an in-frame deletion of the first four codons of exon 15 (Aretz S, Hum. Mutat. 2004 Nov; 24(5):370-80). This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6502 samples (13004 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.005% (greater than 21000 alleles tested) in our clinical cohort. This nucleotide position is highly conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to abolish the native acceptor splice site. Alterations that disrupt the canonical splice acceptor site are typically deleterious in nature (ACMG Recommendations for Standards for Interpretation and Reporting of Sequence Variations. Revision 2007. Genet Med. 2008;10:294). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	30
DANN	Uncertain	0.99
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.99	D
GERP RS		5.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.95
SpliceAI score (max)		0.93		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.93		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs876658214; hg19: chr5-112173248;