5-112835164-A-G

Position:

• chr5-112835164-A-G

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000038.6(APC):​c.1957A>G​(p.Arg653Gly) variant causes a missense, splice region 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. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R653K) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• 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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a repeat ARM 5 (size 44) in uniprot entity APC_HUMAN there are 7 pathogenic changes around while only 1 benign (88%) in NM_000038.6
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr5-112835165-G-A is described in Lovd as [Pathogenic].
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. Scorers claiming Uncertain: max_spliceai. No scorers claiming Benign.
• PP5: Variant 5-112835164-A-G is Pathogenic according to our data. Variant chr5-112835164-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 428139.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr5-112835164-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.1957A>G	p.Arg653Gly	missense_variant, splice_region_variant	15/16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.1957A>G	p.Arg653Gly	missense_variant, splice_region_variant	15/16	5	NM_000038.6	ENSP00000257430	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	May 03, 2023	This variant is considered pathogenic. mRNA analysis has demonstrated abnormal mRNA splicing occurs [PMID: 15459959]. -
Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 03, 2023	This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 653 of the APC protein (p.Arg653Gly). RNA analysis indicates that this missense change induces altered splicing and likely disrupts the C-terminus of the protein. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with familial adenomatous polyposis (PMID: 15459959, 19444466, 20223039, 26446593). ClinVar contains an entry for this variant (Variation ID: 428139). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. Studies have shown that this missense change results in skipping of exon 15 and introduces a new termination codon (PMID: 15459959, 24599579). However the mRNA is not expected to undergo nonsense-mediated decay. This variant disrupts a region of the APC protein in which other variant(s) (p.Tyr2645Lysfs*14) have been determined to be pathogenic (PMID: 1316610, 8381579, 9824584, 22135120, 27081525; Invitae). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided 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

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 12, 2015

The p.R653G variant (also known as c.1957A>G), located in coding exon 14 of the APC gene, results from an A to G substitution at nucleotide position 1957, which is the next to last nucleotide of the exon. The arginine at codon 653 is replaced by glycine, an amino acid with dissimilar properties. This alteration, located in the Armadillo repeat domain of the APC gene, has been reported in an individual diagnosed with >100 adenomas at age 27y (Aretz S et al. Hum Mutat. 2004 Nov;24(5):370-80). In vitro and ex vivo splicing assays showed skipping of exon 14 which causes a major splicing defect (Aretz S et al. Hum Mutat. 2004 Nov;24(5):370-80; Grandval P et al. Hum Mutat. 2014 May;35(5):532-6). 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. This nucleotide position is highly conserved in available vertebrate species. Using the ESEfinder splice site prediction tool, this alteration is prediced to weaken the efficiency of the native splice donor site. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Based on the available evidence, p.R653G is classified as a pathogenic mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.38	D
BayesDel_noAF	Pathogenic	0.31
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.74	.;D;D;D;D
Eigen	Pathogenic	0.82
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	D;.;D;D;D
M_CAP	Pathogenic	0.31	D
MetaRNN	Pathogenic	0.90	D;D;D;D;D
MetaSVM	Uncertain	0.14	D
MutationAssessor	Uncertain	2.1	.;M;M;.;.
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.86	D
PROVEAN	Pathogenic	-6.7	D;D;D;D;.
REVEL	Pathogenic	0.86
Sift	Uncertain	0.0010	D;D;D;D;.
Sift4G	Pathogenic	0.0010	D;D;D;D;D
Polyphen		1.0	.;D;D;.;.
Vest4		0.93, 0.86
MutPred		0.71		.;Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);Loss of helix (P = 0.0626);.;
MVP		0.95
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.99
gMVP		0.92

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.50		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.50		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs1114167580; hg19: chr5-112170861; COSMIC: COSV57367785;