19-1461154-G-C

Position:

• chr19-1461154-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PVS1_Moderate PM2 PP5

The NM_005883.3(APC2):​c.1638+1G>C variant causes a splice donor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: APC2 NM_005883.3 splice_donor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 8.86

Genes affected

APC2 (HGNC:24036): (APC regulator of WNT signaling pathway 2) This gene encodes a strongly conserved protein that has an N-terminal coiled-coil domain followed by an armadillo domain, five 20-amino acid repeats, and two SAMP domains. This protein promotes the assembly of a multiprotein complex that recruits and phosphorylates the Wnt effector beta-catenin and targets beta-catenin for ubiquitylation and proteasomal degradation. This protein therefore plays a role in the reduction of cytoplasmic levels of beta-catenin which in turn reduces activation of Wnt target genes that play a pivotal role in the pathogenesis of various human cancers. The protein encoded by this gene is closely related to the adenomatous polyposis coli (APC) tumor-suppressor protein and has similar tumor-suppressor effects. This gene also plays a role in actin assembly, cell-cell adhesion, and microtubule network formation through its interaction with cytoskeletal proteins. This gene has its highest expression in the central nervous system and is involved in brain development through cytoskeletal regulation in neurons. Alternative splicing produces multiple transcript variants encoding distinct isoforms. [provided by RefSeq, May 2017]

C19orf25 (HGNC:26711): (chromosome 19 open reading frame 25)

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.016782407 fraction of the gene. Cryptic splice site detected, with MaxEntScore 6.2, offset of 11, new splice context is: ccgGTgggc. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 19-1461154-G-C is Pathogenic according to our data. Variant chr19-1461154-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 3057693.Status of the report is no_assertion_criteria_provided, 0 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
APC2	NM_005883.3	c.1638+1G>C		splice_donor_variant		ENST00000590469.6	NP_005874.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
APC2	ENST00000590469.6	c.1638+1G>C		splice_donor_variant		1	NM_005883.3	ENSP00000467073	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

APC2-related disorder Pathogenic:1

Likely pathogenic, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jan 05, 2024

The APC2 c.1638+1G>C variant is predicted to disrupt the GT donor site and interfere with normal splicing. To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. Variants that disrupt the consensus splice donor site in APC2 are expected to be pathogenic. This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D;D;D
GERP RS		4.1
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.93
SpliceAI score (max)		0.95		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.95		Position offset: -1

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr19-1461153;