chr5-112792479-G-T

Variant names:

• chr5-112792479-G-T
• rs1554074749
• NM_000038.6:c.679G>T

Variant summary

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

The NM_000038.6(APC):​c.679G>T​(p.Asp227Tyr) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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:2
• Conservation: PhyloP100: 6.92

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 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
APC	NM_000038.6	c.679G>T	p.Asp227Tyr	missense_variant	Exon 7 of 16	ENST00000257430.9	NP_000029.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
APC	ENST00000257430.9	c.679G>T	p.Asp227Tyr	missense_variant	Exon 7 of 16	5	NM_000038.6	ENSP00000257430.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Uncertain:1

Jan 02, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. 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: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with APC-related disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces aspartic acid with tyrosine at codon 227 of the APC protein (p.Asp227Tyr). The aspartic acid residue is moderately conserved and there is a large physicochemical difference between aspartic acid and tyrosine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Mar 24, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.D227Y variant (also known as c.679G>T), located in coding exon 6 of the APC gene, results from a G to T substitution at nucleotide position 679. The aspartic acid at codon 227 is replaced by tyrosine, an amino acid with highly dissimilar properties. This amino acid position is conserved. In addition, in silico predictors for this gene do not accurately predict pathogenicity. Based on the available evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.72
BayesDel_addAF	Pathogenic	0.44	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.63	D;D;T
Eigen	Pathogenic	0.74
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	.;D;D
M_CAP	Uncertain	0.20	D
MetaRNN	Uncertain	0.74	D;D;D
MetaSVM	Pathogenic	0.91	D
MutationAssessor	Uncertain	2.4	M;M;.
PrimateAI	Pathogenic	0.79	T
PROVEAN	Benign	-1.8	N;N;D
REVEL	Pathogenic	0.70
Sift	Uncertain	0.0020	D;D;D
Sift4G	Uncertain	0.0040	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.89
MutPred		0.29		Gain of helix (P = 0.0496);Gain of helix (P = 0.0496);Gain of helix (P = 0.0496);
MVP		0.98
ClinPred		0.97	D
GERP RS		5.2
Varity_R		0.82
gMVP		0.69

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: rs1554074749; hg19: chr5-112128176;