NM_000038.6:c.968G>C

Variant names:

• chr5-112819000-G-C
• rs1554079954
• NM_000038.6:c.968G>C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000038.6(APC):​c.968G>C​(p.Gly323Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: APC NM_000038.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 8.03

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 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.31846875).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APC	NM_000038.6	c.968G>C	p.Gly323Ala	missense_variant	Exon 10 of 16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.968G>C	p.Gly323Ala	missense_variant	Exon 10 of 16	5	NM_000038.6	ENSP00000257430.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Uncertain:2

Oct 29, 2019

Division of Medical Genetics, University of Washington

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

To our knowledge, this sequence variant has not been previously reported in the literature. This variant has an overall allele frequency of 0.0001, and an allele frequency of 0.00004 in African ancestry populations, in the Broad Institute gnomAD Browser (https://gnomad.broadinstitute.org/). This allele frequency is likely too high for this variant to be associated with the classic form of FAP. In silico analyses indicate that this variant does not alter protein structure/function. Thus, it is unknown at this time whether this variant increases cancer risk. BP4; BS1 -

Jan 13, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine with alanine at codon 323 of the APC protein (p.Gly323Ala). The glycine residue is highly conserved and there is a small physicochemical difference between glycine and alanine. In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0"). This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with an APC-related disease. -

Hereditary cancer-predisposing syndrome Uncertain:1

Jan 20, 2017

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G323A variant (also known as c.968G>C), located in coding exon 9 of the APC gene, results from a G to C substitution at nucleotide position 968. The glycine at codon 323 is replaced by alanine, an amino acid with similar properties. This amino acid position is highly 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	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
CADD	Uncertain	25
DANN	Benign	0.88
DEOGEN2	Uncertain	0.51	.;D;D;T
Eigen	Uncertain	0.23
Eigen_PC	Uncertain	0.41
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.85	D;.;D;D
M_CAP	Benign	0.031	D
MetaRNN	Benign	0.32	T;T;T;T
MetaSVM	Uncertain	0.21	D
MutationAssessor	Benign	1.3	.;L;L;.
PrimateAI	Pathogenic	0.94	D
PROVEAN	Benign	-0.21	N;N;N;N
REVEL	Uncertain	0.41
Sift	Benign	0.40	T;T;T;T
Sift4G	Benign	0.61	T;T;T;T
Polyphen		0.13	.;B;B;.
Vest4		0.54, 0.48
MutPred		0.10		.;Loss of loop (P = 0.0374);Loss of loop (P = 0.0374);Loss of loop (P = 0.0374);
MVP		0.95
ClinPred		0.55	D
GERP RS		5.7
Varity_R		0.14
gMVP		0.47

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: rs1554079954; hg19: chr5-112154697;