chr5-112840859-G-GTCT

Variant names:

• chr5-112840859-G-GTCT
• rs780061589
• NM_000038.6:c.5272_5274dupTCT

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PM4_Supporting

The NM_000038.6(APC):​c.5272_5274dupTCT​(p.Ser1758dup) variant causes a conservative inframe insertion change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A1759A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 conservative_inframe_insertion
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.258
• 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: Uncertain_significance. The variant received 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_000038.6. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APC	NM_000038.6	c.5272_5274dupTCT	p.Ser1758dup	conservative_inframe_insertion	Exon 16 of 16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.5272_5274dupTCT	p.Ser1758dup	conservative_inframe_insertion	Exon 16 of 16	5	NM_000038.6	ENSP00000257430.4
ENSG00000258864	ENST00000520401.1	n.228+11894_228+11896dupTCT		intron_variant	Intron 3 of 7	3		ENSP00000454861.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 63

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Feb 28, 2020

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.5272_5274dupTCT variant (also known as p.S1758dup), located in coding exon 15 of the APC gene, results from an in-frame duplication of TCT at nucleotide positions 5272 to 5274. This results in the duplication of an extra serine residue between codons 1758 and 1759. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be neutral by in silico analysis (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Oct 25, 2018

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial adenomatous polyposis 1 Uncertain:1

Mar 08, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. ClinVar contains an entry for this variant (Variation ID: 924884). This variant, c.5272_5274dup, results in the insertion of 1 amino acid(s) of the APC protein (p.Ser1758dup), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with APC-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.26

Splicing

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

Other links and lift over

dbSNP: rs780061589; hg19: chr5-112176556;