rs1554069584

Positions:

• chr5-112766415-A-G
• chr5-112766415-A-T

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000038.6(APC):​c.220+5A>G variant causes a splice donor 5th base, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: APC NM_000038.6 splice_donor_5th_base, intron
• Scores: Splicing: ADA: 0.0003402
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.40

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
APC	NM_000038.6	c.220+5A>G		splice_donor_5th_base_variant, intron_variant		ENST00000257430.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
APC	ENST00000257430.9	c.220+5A>G		splice_donor_5th_base_variant, intron_variant		5	NM_000038.6	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial adenomatous polyposis 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 01, 2021

This sequence change falls in intron 3 of the APC gene. It does not directly change the encoded amino acid sequence of the APC protein. It affects a nucleotide within the consensus splice site of the intron. This variant is not present in population databases (ExAC 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: 469732). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant is not likely to affect RNA splicing. 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 11, 2023

The c.220+5A>G intronic variant results from an A to G substitution 5 nucleotides after coding exon 2 in the APC gene. This nucleotide position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will not have any significant effect on splicing. 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
BayesDel_noAF	Benign	-0.82
CADD	Benign	16
DANN	Benign	0.63

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00034
dbscSNV1_RF	Benign	0.13
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: rs1554069584; hg19: chr5-112102112;