5-112828856-G-T

Variant names:

• chr5-112828856-G-T
• rs1554082080
• NM_000038.6:c.1627G>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 3P and 1B. PS3_Moderate PM2_Supporting BP1

This summary comes from the ClinGen Evidence Repository: The c.1627G>T variant in APC is a missense variant predicted to cause a substitution of valine by phenylalanine at amino acid position 543 (p.Val543Phe). This variant is located at the first base of exon 14. RT-PCR of the exons flanking the target site in a patient with AFAP shows that the variant c.1627G>T impacts splicing by leading to exon 14 skipping, which is an in-frame event (PS3_Moderate; PMID22987206). This variant scored 0.5 phenotype points based on information available in 3 individuals (PS4_variable not met; PMID 22987206, Invitae internal data). This variant is absent from gnomAD v2.1.1 (PM2_supporting). In silico predictions by SpliceAI, MaxEntScan and VarSEAK showed conflicting results (PP3 not met). APC is defined by the ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (HCCP VCEP) as a gene for which primarily truncating variants are known to cause disease (BP1). In summary, this is a Variant of Uncertain Significance (VUS) for FAP based on the ACMG/AMP criteria applied, as specified by the HCCP VCEP: BP1, PS3_moderate, and PM2_supporting. (VCEP specifications version 1; date of approval: 12/12/2022). LINK:https://erepo.genome.network/evrepo/ui/classification/CA16024864/MONDO:0021056/089

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance reviewed by expert panel U:4
• Conservation: PhyloP100: 9.60
• 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

ENSG00000258864 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PS3: For more information check the summary or visit ClinGen Evidence Repository.
• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• BP1: For more information check the summary or visit ClinGen Evidence Repository.

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.1627G>T	p.Val543Phe	missense splice_region	Exon 14 of 16	NP_000029.2
	APC	NM_001407446.1		c.1711G>T	p.Val571Phe	missense splice_region	Exon 14 of 16	NP_001394375.1
	APC	NM_001354896.2		c.1681G>T	p.Val561Phe	missense splice_region	Exon 15 of 17	NP_001341825.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	APC	ENST00000257430.9	TSL:5 MANE Select	c.1627G>T	p.Val543Phe	missense splice_region	Exon 14 of 16	ENSP00000257430.4
	APC	ENST00000508376.6	TSL:1	c.1627G>T	p.Val543Phe	missense splice_region	Exon 15 of 17	ENSP00000427089.2
	APC	ENST00000505084.2	TSL:1	n.1683G>T		splice_region non_coding_transcript_exon	Exon 14 of 14

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: reviewed by expert panel

Submissions by phenotype

Familial adenomatous polyposis 1 Uncertain:2

Feb 19, 2023

ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The c.1627G>T variant in APC is a missense variant predicted to cause a substitution of valine by phenylalanine at amino acid position 543 (p.Val543Phe). This variant is located at the first base of exon 14. RT-PCR of the exons flanking the target site in a patient with AFAP shows that the variant c.1627G>T impacts splicing by leading to exon 14 skipping, which is an in-frame event (PS3_Moderate; PMID22987206). This variant scored 0.5 phenotype points based on information available in 3 individuals (PS4_variable not met; PMID 22987206, Invitae internal data). This variant is absent from gnomAD v2.1.1 (PM2_supporting). In silico predictions by SpliceAI, MaxEntScan and VarSEAK showed conflicting results (PP3 not met). APC is defined by the ClinGen InSiGHT Hereditary Colorectal Cancer/Polyposis Variant Curation Expert Panel (HCCP VCEP) as a gene for which primarily truncating variants are known to cause disease (BP1). In summary, this is a Variant of Uncertain Significance (VUS) for FAP based on the ACMG/AMP criteria applied, as specified by the HCCP VCEP: BP1, PS3_moderate, and PM2_supporting. (VCEP specifications version 1; date of approval: 12/12/2022).

Sep 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces valine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 543 of the APC protein (p.Val543Phe). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of attenuated familial adenomatous polyposis (PMID: 22987206). ClinVar contains an entry for this variant (Variation ID: 490221). 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 is associated with inconclusive levels of altered splicing (PMID: 22987206; internal data). 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.

Hereditary cancer-predisposing syndrome Uncertain:2

Jun 03, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.V543F variant (also known as c.1627G>T) is located in coding exon 13 of the APC gene. The valine at codon 543 is replaced by phenylalanine, an amino acid with highly similar properties. This change occurs in the first base pair of coding exon 13. This variant was detected in a 63-year-old patient that with reported attenuated FAP that underwent subtotal colectomy due to a "field of polyps" (Schwarzová L et al. Fam Cancer, 2013 Mar;12:35-42). Missense alterations in APC are not a common cause of disease (Spier I et al. Genet Med. 2024 Feb;26(2):100992). This amino acid position is highly conserved in available vertebrate species. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Based on the available evidence, the clinical significance of this variant remains unclear.

May 14, 2019

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.34	D
BayesDel_noAF	Pathogenic	0.25
CADD	Pathogenic	33
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.74	D
Eigen	Pathogenic	0.90
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.22	D
MetaRNN	Pathogenic	0.86	D
MetaSVM	Uncertain	0.072	D
MutationAssessor	Benign	1.8	L
PhyloP100		9.6
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-4.8	D
REVEL	Pathogenic	0.77
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.82
MutPred		0.61		Loss of MoRF binding (P = 0.0919)
MVP		0.92
ClinPred		0.99	D
GERP RS		5.6
Varity_R		0.95
gMVP		0.88
Mutation Taster		=2/98	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.010		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: rs1554082080; hg19: chr5-112164553;