Genetic Information

Gene & Transcript Details

Gene
CTNNB1
Transcript
NM_001904.4 MANE Select
Total Exons
Reference Sequence
NC_000003.11
Alternative Transcripts
IDStatusDetails
NM_001904.3 Alternative 3720 nt | 269–2614
NM_001904.4 MANE Select 3661 nt | 215–2560

Variant Details

HGVS Notation
NM_001904.4:c.1161T>A
Protein Change
N387K
Location
Exon 8 (Exon 8 of )
8
5'Exon Structure3'
Functional Consequence
Loss of Function
Alternate Identifiers

Clinical & Population Data

Population Frequency

gnomAD
Global Frequency
0.0 in 100,000
Extremely Rare
ACMG Criteria Applied PM2
This variant is absent or extremely rare in population databases (PM2 criteria applies).

ClinVar

Open
Classification
Unknown
0 publications
Clinical Statement

""

COSMIC Somatic Evidence

Open
COSMIC ID
COSM131449
Recurrence
25 occurrences
PM1 Criteria
Applied
COSMIC Database Preview
COSMIC Preview
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Functional Impact & Domains

Functional Domain

Hotspot Status
Not a hotspot
Domain Summary
This variant is not located in a mutational hotspot or critical domain.
Related Variants in This Domain
No evidence of other pathogenic variants at this position in gene CTNNB1.

Functional Studies & Therapeutic Relevance

Functional Summary

The CTNNB1 N387K variant has been functionally characterized as oncogenic. It is located in the APC/Axin binding region of the β-catenin protein and has been shown to increase transcriptional activity and signaling in cell culture. Additionally, this variant enhances tumor growth in xenograft models, indicating an activating effect compared to the wild-type protein.

Database Previews
OncoKB
OncoKB Preview
JAX-CKB
JAX-CKB Preview

Click on previews to view full database entries. External databases may require institutional access.

Computational Analysis

Pathogenicity Predictions

SpliceAI
Predictor Consensus
Mixed/VUS
PP3 Applied
No
REVEL Score
0.679
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.0 113 bp
- Donor Loss (DL) 0.0 7 bp
+ Acceptor Gain (AG) 0.0 294 bp
+ Donor Gain (DG) 0.0 24 bp
High impact (≥0.5) Medium impact (0.2-0.49) Low impact (<0.2)

VCEP Guidelines

Applied ACMG/AMP Criteria (VCEP Specific)

Filter Criteria:
PVS1

PVS1 (Not Applied)

According to standard ACMG guidelines, the rule for PVS1 is: "Null variant in a gene where loss of function (LoF) is a known mechanism of disease (e.g., nonsense, frameshift, canonical ±1 or 2 splice sites, initiation codon, single exon deletion in a LoF gene)". The evidence for this variant shows: it is a missense change (N387K), not a null variant. Therefore, this criterion is not applied.

PS1

PS1 (Not Applied)

According to standard ACMG guidelines, the rule for PS1 is: "Same amino acid change as a known pathogenic variant but different nucleotide change". The evidence for this variant shows: no prior pathogenic missense change reported at residue N387. Therefore, this criterion is not applied.

PS2

PS2 (Not Applied)

According to standard ACMG guidelines, the rule for PS2 is: "De novo (both maternity and paternity confirmed) in a patient with the disease and no family history". The evidence for this variant shows: no de novo inheritance information provided. Therefore, this criterion is not applied.

PS3

PS3 (Strong)

According to standard ACMG guidelines, the rule for PS3 is: "Well-established functional studies supportive of a damaging effect on the gene or gene product". The evidence for this variant shows: CTNNB1 N387K has been functionally characterized as oncogenic, increases transcriptional activity in cell assays and enhances tumor growth in xenograft models. Therefore, this criterion is applied at Strong strength because functional studies directly demonstrate damaging (activating) effect.

PS4

PS4 (Not Applied)

According to standard ACMG guidelines, the rule for PS4 is: "Prevalence in affected individuals significantly increased compared with controls". The evidence for this variant shows: no case-control data or epidemiological studies available. Therefore, this criterion is not applied.

PM1

PM1 (Moderate)

According to standard ACMG guidelines, the rule for PM1 is: "Located in a mutational hot spot or well-established functional domain without benign variation". The evidence for this variant shows: N387K lies in the APC/Axin binding region, a critical functional domain of β-catenin. Therefore, this criterion is applied at Moderate strength because the variant is in a critical domain with no known benign variation.

PM2

PM2 (Moderate)

According to standard ACMG guidelines, the rule for PM2 is: "Absent from controls (or at extremely low frequency if recessive) in population databases". The evidence for this variant shows: absent from gnomAD and other population datasets. Therefore, this criterion is applied at Moderate strength.

PM3

PM3 (Not Applied)

According to standard ACMG guidelines, the rule for PM3 is: "Detected in trans with a pathogenic variant (for recessive disorders)". The evidence for this variant shows: no trans configuration data available. Therefore, this criterion is not applied.

PM4

PM4 (Not Applied)

According to standard ACMG guidelines, the rule for PM4 is: "Protein length changes due to in-frame deletions/insertions or stop-loss variants". The evidence for this variant shows: it is a missense change without alteration of protein length. Therefore, this criterion is not applied.

PM5

PM5 (Not Applied)

According to standard ACMG guidelines, the rule for PM5 is: "Novel missense change at an amino acid residue where a different pathogenic missense change has been seen". The evidence for this variant shows: no other pathogenic missense variant reported at residue N387. Therefore, this criterion is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, the rule for PM6 is: "Assumed de novo, but without confirmation of paternity and maternity". The evidence for this variant shows: no evidence of de novo occurrence. Therefore, this criterion is not applied.

PP1

PP1 (Not Applied)

According to standard ACMG guidelines, the rule for PP1 is: "Co-segregation with disease in multiple affected family members". The evidence for this variant shows: no familial segregation data. Therefore, this criterion is not applied.

PP2

PP2 (Supporting)

According to standard ACMG guidelines, the rule for PP2 is: "Missense variant in a gene with a low rate of benign missense variation and where missense variants are a common mechanism of disease". The evidence for this variant shows: CTNNB1 disease mechanism is gain-of-function missense, and benign missense variants are rare. Therefore, this criterion is applied at Supporting strength.

PP3

PP3 (Not Applied)

According to standard ACMG guidelines, the rule for PP3 is: "Multiple lines of computational evidence support a deleterious effect on the gene or gene product". The evidence for this variant shows: conflicting in silico predictions (some models pathogenic, some benign). Therefore, this criterion is not applied.

PP4

PP4 (Not Applied)

According to standard ACMG guidelines, the rule for PP4 is: "Patient's phenotype or family history highly specific for a disease with a single genetic etiology". The evidence for this variant shows: no specific phenotypic data provided. Therefore, this criterion is not applied.

PP5

PP5 (Not Applied)

According to standard ACMG guidelines, the rule for PP5 is: "Reputable source reports variant as pathogenic, but without accessible evidence". The evidence for this variant shows: not found in ClinVar or other databases. Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to standard ACMG guidelines, the rule for BA1 is: "Allele frequency is too high for the disorder". The evidence for this variant shows: allele frequency is 0%. Therefore, this criterion is not applied.

BS1

BS1 (Not Applied)

According to standard ACMG guidelines, the rule for BS1 is: "Allele frequency is greater than expected for the disorder". The evidence for this variant shows: allele frequency is 0%. Therefore, this criterion is not applied.

BS2

BS2 (Not Applied)

According to standard ACMG guidelines, the rule for BS2 is: "Observed in healthy individuals with full penetrance expected at an early age". The evidence for this variant shows: no observations in healthy controls. Therefore, this criterion is not applied.

BS3

BS3 (Not Applied)

According to standard ACMG guidelines, the rule for BS3 is: "Well-established functional studies show no damaging effect on protein function or splicing". The evidence for this variant shows: functional studies demonstrate damaging (activating) effect. Therefore, this criterion is not applied.

BS4

BS4 (Not Applied)

According to standard ACMG guidelines, the rule for BS4 is: "Lack of segregation in affected family members". The evidence for this variant shows: no segregation data available. Therefore, this criterion is not applied.

BP1

BP1 (Not Applied)

According to standard ACMG guidelines, the rule for BP1 is: "Missense variant in a gene where only LoF causes disease". The evidence for this variant shows: CTNNB1 disease mechanism is gain-of-function missense. Therefore, this criterion is not applied.

BP2

BP2 (Not Applied)

According to standard ACMG guidelines, the rule for BP2 is: "Observed in trans with a pathogenic variant for dominant disorders or in cis with a pathogenic variant". The evidence for this variant shows: no such observations. Therefore, this criterion is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, the rule for BP3 is: "In-frame deletions/insertions in a repetitive region without known function". The evidence for this variant shows: it is a substitution, not an in-frame indel. Therefore, this criterion is not applied.

BP4

BP4 (Not Applied)

According to standard ACMG guidelines, the rule for BP4 is: "Multiple lines of computational evidence suggest no impact on gene or gene product". The evidence for this variant shows: conflicting in silico predictions. Therefore, this criterion is not applied.

BP5

BP5 (Not Applied)

According to standard ACMG guidelines, the rule for BP5 is: "Variant found in a case with an alternate molecular basis for disease". The evidence for this variant shows: no such alternate molecular basis reported. Therefore, this criterion is not applied.

BP6

BP6 (Not Applied)

According to standard ACMG guidelines, the rule for BP6 is: "Reputable source reports variant as benign, but without accessible evidence". The evidence for this variant shows: no benign reports in databases. Therefore, this criterion is not applied.

BP7

BP7 (Not Applied)

According to standard ACMG guidelines, the rule for BP7 is: "Synonymous variant with no predicted impact on splicing". The evidence for this variant shows: it is a missense variant, not synonymous. Therefore, this criterion is not applied.