5-112844108-C-G

Position:

• chr5-112844108-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP5

The NM_000038.6(APC):​c.8514C>G​(p.Tyr2838Ter) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. Y2838Y) has been classified as Benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 stop_gained
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 2.62

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]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 4 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 5-112844108-C-G is Pathogenic according to our data. Variant chr5-112844108-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 233392.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=1, Pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
APC	NM_000038.6	c.8514C>G	p.Tyr2838Ter	stop_gained	16/16	ENST00000257430.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
APC	ENST00000257430.9	c.8514C>G	p.Tyr2838Ter	stop_gained	16/16	5	NM_000038.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 30, 2021

The p.Y2838* variant (also known as c.8514C>G), located in coding exon 15 of the APC gene, results from a C to G substitution at nucleotide position 8514. This changes the amino acid from a tyrosine to a stop codon within coding exon 15. This alteration occurs at the 3' terminus of the APC gene, is not expected to trigger nonsense mediated mRNA decay, and only impacts the last 6 amino acids of the protein. However, premature stop codons are typically deleterious in nature and structural analysis suggests this deletion removes a known motif (Thr2841-Ser2842-Val2843) needed for protein binding involved in regulation of protein function (Slep KC et al, PLoS ONE 2012; 7(11):e50097; Zhang Z et al, PLoS ONE 2011; 6(8):e23507). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Familial adenomatous polyposis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 02, 2021

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with APC-related conditions. ClinVar contains an entry for this variant (Variation ID: 233392). This variant is not present in population databases (ExAC no frequency). This sequence change creates a premature translational stop signal (p.Tyr2838*) in the APC gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 6 amino acid(s) of the APC protein. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	38
DANN	Uncertain	0.99
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.98	D
MutationTaster	Benign	1.0	D;D;D
Vest4		0.72
GERP RS		5.0

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

LitVar

Other links and lift over

dbSNP: rs876660375; hg19: chr5-112179805;