5-112815578-T-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM1BP4

The NM_000038.6(APC):c.918T>G(p.Ser306Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000366 in 1,610,922 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 Conflicting classifications of pathogenicity (no stars). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S306I) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000039 ( 0 hom. )

Consequence

APC
NM_000038.6 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:10B:2

Conservation

PhyloP100: 2.62

Publications

4 publications found

Variant links:

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

APC links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 43 uncertain in NM_000038.6

BP4

Computational evidence support a benign effect (MetaRNN=0.41249102).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APC	NM_000038.6 link	c.918T>G	p.Ser306Arg	missense_variant	Exon 9 of 16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9 link	c.918T>G	p.Ser306Arg	missense_variant	Exon 9 of 16	5	NM_000038.6	ENSP00000257430.4

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152166

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000239

AC:

AN:

251136

AF XY:

0.0000442

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000528

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000391

AC:

AN:

1458756

Hom.:

Cov.:

AF XY:

0.0000358

AC XY:

AN XY:

725820

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33358

American (AMR)

AF:

0.00

AC:

AN:

44630

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26048

East Asian (EAS)

AF:

0.00

AC:

AN:

39538

South Asian (SAS)

AF:

0.00

AC:

AN:

86216

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53146

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5738

European-Non Finnish (NFE)

AF:

0.0000487

AC:

AN:

1109942

Other (OTH)

AF:

0.0000499

AC:

AN:

60140

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.470

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000131

AC:

AN:

152166

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74328

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41438

American (AMR)

AF:

0.00

AC:

AN:

15256

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5196

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

68042

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.600

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000340

Hom.:

Bravo

AF:

0.00000756

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:10Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Familial adenomatous polyposis 1

Uncertain:4

Jan 19, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces serine, which is neutral and polar, with arginine, which is basic and polar, at codon 306 of the APC protein (p.Ser306Arg). This variant is present in population databases (rs730881231, gnomAD 0.005%). 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: 181783). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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.

Jan 25, 2018

Counsyl

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com.

Feb 17, 2023

Myriad Genetics, Inc.

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk.

Sep 19, 2023

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

not specified

Uncertain:2

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Sep 06, 2019

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: APC c.918T>G (p.Ser306Arg) 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 allele was found at a frequency of 2.4e-05 in 251136 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.918T>G in individuals affected with Familial Adenomatous Polyposis and no experimental evidence demonstrating its impact on protein function have been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance.

Hereditary cancer-predisposing syndrome

Benign:2

Jan 06, 2025

Color Diagnostics, LLC DBA Color Health

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Mar 10, 2023

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.

not provided

Uncertain:1

Oct 03, 2023

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with melanoma (Yehia et al., 2018); This variant is associated with the following publications: (PMID: 29684080)

Classic or attenuated familial adenomatous polyposis

Uncertain:1

Oct 27, 2023

All of Us Research Program, National Institutes of Health

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This missense variant replaces serine with arginine at codon 306 of the APC protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with APC-related disorders in the literature. This variant has been identified in 6/251136 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance.

Gardner syndrome;C5679615:APC-related attenuated familial adenomatous polyposis

Uncertain:1

Sep 08, 2020

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

APC-related disorder

Uncertain:1

Apr 18, 2024

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The APC c.918T>G variant is predicted to result in the amino acid substitution p.Ser306Arg. This variant, along with another missense change in the same gene, has been reported in a cohort study of individuals with Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome (S9 Table, Yehia et al 2018. PubMed ID: 29684080). This variant is reported in 0.0053% of alleles in individuals of European (Non-Finnish) descent in gnomAD. This variant is interpreted as a variant of uncertain significance by majority of the submitters in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/181783/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence.

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.95

BayesDel_addAF

Uncertain

0.16

BayesDel_noAF

Pathogenic

0.15

CADD

Uncertain

(source)

DANN

Uncertain

1.0

DEOGEN2

Benign

0.0

.;T;T;T

Eigen

Uncertain

0.35

Eigen_PC

Uncertain

0.34

FATHMM_MKL

Uncertain

0.93

LIST_S2

Uncertain

0.94

D;.;D;D

M_CAP

Pathogenic

0.36

MetaRNN

Benign

0.41

T;T;T;T

MetaSVM

Uncertain

0.58

MutationAssessor

Benign

0.0

.;M;M;.

PhyloP100

2.6

PrimateAI

Pathogenic

0.88

PROVEAN

Benign

-1.9

N;N;N;N

REVEL

Uncertain

0.61

Sift

Uncertain

0.024

D;D;D;D

Sift4G

Benign

0.097

T;T;T;T

Vest4

0.0

ClinPred

0.54

GERP RS

3.9

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.38

gMVP

0.59

Mutation Taster

=35/65

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

Splicevardb

2.0

SpliceAI score (max)

0.080

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over