rs1168791940

Positions:

• chr5-112780850-G-A
• chr5-112780850-G-C
• chr5-112780850-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 4P and 1B. PM1 PM2 BP4

The NM_000038.6(APC):​c.592G>A​(p.Val198Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,272 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: APC NM_000038.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.83

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 3 ACMG points.

• PM1: In a coiled_coil_region (size 121) in uniprot entity APC_HUMAN there are 9 pathogenic changes around while only 3 benign (75%) in NM_000038.6
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2780406).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APC	NM_000038.6	c.592G>A	p.Val198Ile	missense_variant	6/16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.592G>A	p.Val198Ile	missense_variant	6/16	5	NM_000038.6	ENSP00000257430.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461272 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 726920

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.0000505

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Asia WGS AF: 0.000289 AC: 1 AN: 3478

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

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jan 12, 2017

The p.Val198Ile variant in APC has not been previously reported in individuals w ith APC-associated polyposis or in large population studies. Computational predi ction tools and conservation analysis suggest that the p.Val198Ile variant may n ot impact the protein, though this information is not predictive enough to rule out pathogenicity. In summary, the clinical significance of the p.Val198Ile vari ant is uncertain. -

Familial adenomatous polyposis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 06, 2024

This sequence change replaces valine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 198 of the APC protein (p.Val198Ile). 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: 505513). 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

Nov 27, 2024

The p.V198I variant (also known as c.592G>A), located in coding exon 5 of the APC gene, results from a G to A substitution at nucleotide position 592. The valine at codon 198 is replaced by isoleucine, an amino acid with highly similar properties. This alteration was detected in a study of 1,165 individuals with a history of colorectal cancer or colon polyps as well as 590 controls (Gordon AS et al. Am J Hum Genet, 2019 09;105:526-533). 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 not well conserved in available vertebrate species. 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	Benign	0.084
BayesDel_addAF	Benign	-0.048	T
BayesDel_noAF	Benign	-0.31
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.40	.;T;T;T
Eigen	Benign	-0.033
Eigen_PC	Benign	0.20
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.95	D;.;T;T
M_CAP	Benign	0.019	T
MetaRNN	Benign	0.28	T;T;T;T
MetaSVM	Benign	-0.70	T
MutationAssessor	Benign	0.0	.;N;N;.
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-0.43	N;N;N;N
REVEL	Uncertain	0.33
Sift	Uncertain	0.018	D;D;D;D
Sift4G	Benign	0.079	T;T;T;T
Polyphen		0.0060	.;B;B;.
Vest4		0.32, 0.37
MutPred		0.27		.;Loss of loop (P = 0.0022);Loss of loop (P = 0.0022);Loss of loop (P = 0.0022);
MVP		0.72
ClinPred		0.89	D
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.14
gMVP		0.099

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: rs1168791940; hg19: chr5-112116547;