rs72541813

Positions:

• chr5-112840359-C-A
• chr5-112840359-C-G
• chr5-112840359-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000038.6(APC):​c.4765C>A​(p.Arg1589Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,872 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1589C) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: APC NM_000038.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.54

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 Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 15 uncertain in NM_000038.6
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
APC	NM_000038.6	c.4765C>A	p.Arg1589Ser	missense_variant	16/16	ENST00000257430.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
APC	ENST00000257430.9	c.4765C>A	p.Arg1589Ser	missense_variant	16/16	5	NM_000038.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461872 Hom.: 0 Cov.: 66 AF XY: 0.00 AC XY: 0 AN XY: 727244

Gnomad4 AFR exome AF: 0.0000597

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Jun 29, 2020

Variant summary: APC c.4765C>A (p.Arg1589Ser) results in a non-conservative amino acid change in the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251116 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.4765C>A in individuals affected with Familial Adenomatous Polyposis and no experimental evidence demonstrating its impact on protein function have been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Familial adenomatous polyposis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 18, 2023

This sequence change replaces arginine, which is basic and polar, with serine, which is neutral and polar, at codon 1589 of the APC protein (p.Arg1589Ser). 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. ClinVar contains an entry for this variant (Variation ID: 933161). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt APC protein function with a negative predictive value of 95%. 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:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 01, 2024

The p.R1589S variant (also known as c.4765C>A), located in coding exon 15 of the APC gene, results from a C to A substitution at nucleotide position 4765. The arginine at codon 1589 is replaced by serine, an amino acid with dissimilar properties. This amino acid position is conserved. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.43
BayesDel_addAF	Uncertain	0.072	D
BayesDel_noAF	Benign	-0.13
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.59	D;D
Eigen	Benign	0.066
Eigen_PC	Benign	0.18
FATHMM_MKL	Uncertain	0.89	D
M_CAP	Uncertain	0.16	D
MetaRNN	Uncertain	0.43	T;T
MetaSVM	Uncertain	0.11	D
MutationAssessor	Benign	1.9	L;L
MutationTaster	Benign	0.83	D;D;D
PrimateAI	Benign	0.25	T
PROVEAN	Benign	-1.8	N;N
REVEL	Uncertain	0.34
Sift	Uncertain	0.011	D;D
Sift4G	Uncertain	0.022	D;D
Polyphen		0.72	P;P
Vest4		0.40
MutPred		0.44		Loss of helix (P = 0.0076);Loss of helix (P = 0.0076);
MVP		0.83
ClinPred		0.83	D
GERP RS		5.3
Varity_R		0.47
gMVP		0.55

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: rs72541813; hg19: chr5-112176056;