Genetic Information

Gene & Transcript Details

Gene
PIK3CA
Transcript
NM_006218.4 MANE Select
Total Exons
Reference Sequence
NC_000003.11
Alternative Transcripts
IDStatusDetails
NM_006218.2 Alternative 3724 nt | 158–3364
NM_006218.3 Alternative 9104 nt | 158–3364
NM_006218.4 MANE Select 9259 nt | 324–3530

Variant Details

HGVS Notation
NM_006218.4:c.1265del
Protein Change
L422Wfs*6
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

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COSMIC Somatic Evidence

Open
COSMIC ID
COSM9232869
Recurrence
1 occurrences
PM1 Criteria
Not 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 PIK3CA.

Functional Studies & Therapeutic Relevance

Functional Summary

The variant PIK3CA L422Wfs*6 is a truncating mutation in the PIK3CA gene, which is an oncogene. Truncating mutations in oncogenes are typically nonfunctional, suggesting a potential damaging effect. However, no specific functional characterization data for this variant is available.

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
Unknown
PP3 Applied
No
REVEL Score
0.0
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.02 215 bp
- Donor Loss (DL) 0.0 146 bp
+ Acceptor Gain (AG) 0.07 38 bp
+ Donor Gain (DG) 0.0 322 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 (Very Strong)

According to standard ACMG guidelines, the rule for PVS1 is: 'Null Variant (nonsense, fs, start codon, splicing +1/2, startgain, single or multi-exon deletion) in a gene where LOF is a known mechanism of disease'. The evidence for this variant shows: c.1265del causes a frameshift (L422Wfs*6) predicted to result in premature truncation in a gene where loss of function is established as a disease mechanism and the variant is not in the last exon. Therefore, this criterion is applied at Very Strong strength because it is a null variant in a LOF‐sensitive gene.

PS1

PS1 (Not Applied)

According to VCEP guidelines, the rule for PS1 is: 'Strong Strength: Strong No change. Modification Type: None'. The evidence for this variant shows: there is no previously reported pathogenic variant causing the identical amino acid change. Therefore, PS1 is not applied.

PS2

PS2 (Not Applied)

According to VCEP guidelines, the rule for PS2 (de novo) is: 'Strong Strength: Award PS2_Strong if Criteria 1 AND Criteria 2 are fulfilled; Moderate Strength: Award PS2_Moderate if one criterion is fulfilled'. The evidence for this variant shows: no parental testing or tissue mosaicism data are available. Therefore, PS2 is not applied.

PS3

PS3 (Not Applied)

According to VCEP guidelines, the rule for PS3 is: 'Strong Strength: functional assays meeting VCEP‐specified quality metrics; Moderate/Supporting per assay validation'. The evidence for this variant shows: no specific functional assay data are available for L422Wfs*6. Therefore, PS3 is not applied.

PS4

PS4 (Not Applied)

According to VCEP guidelines, the rule for PS4 is: 'Points‐based phenotypic data only if variant is absent from controls (PM2); strength assigned by total points'. The evidence for this variant shows: no case‐level clinical reports or aggregate phenotypic data. Therefore, PS4 is not applied.

PM1

PM1 (Not Applied)

According to VCEP guidelines, the rule for PM1 is: 'Supporting Strength: residues affecting critical functional domains provided in Table 4'. The evidence for this variant shows: L422 is not located in a defined hotspot or critical domain per VCEP Table 4. Therefore, PM1 is not applied.

PM2

PM2 (Supporting)

According to VCEP guidelines, the rule for PM2 is: 'Supporting Strength: Absent/rare from controls in an ethnically‐matched cohort population sample (≥1)'. The evidence for this variant shows: it is absent from gnomAD and other population databases (MAF=0%). Therefore, PM2 is applied at Supporting strength.

PM3

PM3 (Not Applied)

According to standard ACMG guidelines, the rule for PM3 is: 'Detected in trans with a pathogenic variant for a recessive disorder'. The evidence for this variant shows: PIK3CA‐related conditions are not purely recessive and no in trans data are available. Therefore, PM3 is not applied.

PM4

PM4 (Not Applied)

According to standard ACMG guidelines, the rule for PM4 is: 'Protein length change due to in-frame deletion/insertion in non-repeat region or stop-loss'. The evidence for this variant shows: it is a frameshift, not an in-frame indel. Therefore, PM4 is not applied.

PM5

PM5 (Not Applied)

According to VCEP guidelines, the rule for PM5 is: 'Moderate Strength: no change from standard ACMG; different amino acid change at same residue'. The evidence for this variant shows: it is a frameshift, not a missense change. Therefore, PM5 is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, the rule for PM6 is: 'Assumed de novo, but without confirmation of maternity/paternity'. The evidence for this variant shows: no de novo data. Therefore, PM6 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 segregation data. Therefore, PP1 is not applied.

PP2

PP2 (Not Applied)

According to VCEP guidelines, the rule for PP2 is: 'Supporting Strength: missense constraint z-score >3.09 for PIK3CA'. The evidence for this variant shows: it is a frameshift, not a missense. Therefore, PP2 is not applied.

PP3

PP3 (Not Applied)

According to standard ACMG guidelines, the rule for PP3 is: 'Multiple computational lines of evidence support a deleterious effect'. The evidence for this variant shows: no in silico predictions were provided for this frameshift. Therefore, PP3 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 phenotype data are available. Therefore, PP4 is not applied.

PP5

PP5 (Not Applied)

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

BA1

BA1 (Not Applied)

According to VCEP guidelines, the rule for BA1 is: 'Stand Alone Strength: allele frequency >0.0926%'. The evidence for this variant shows: absent from population databases. Therefore, BA1 is not applied.

BS1

BS1 (Not Applied)

According to VCEP guidelines, the rule for BS1 is: 'Strong Strength: allele frequency >0.0185%'. The evidence for this variant shows: absent from population databases. Therefore, BS1 is not applied.

BS2

BS2 (Not Applied)

According to VCEP guidelines, the rule for BS2 is: 'Strong Strength: ≥3 homozygotes or heterozygotes in healthy individuals'. The evidence for this variant shows: no occurrences in population databases. Therefore, BS2 is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, the rule for BS3 is: 'Strong Strength: well-validated functional assays show no damaging effect'. The evidence for this variant shows: no functional assays. Therefore, BS3 is not applied.

BS4

BS4 (Not Applied)

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

BP1

BP1 (Not Applied)

According to standard ACMG guidelines, the rule for BP1 is: 'Missense variant in gene where only LOF causes disease'. The evidence for this variant shows: it is a frameshift, not missense. Therefore, BP1 is not applied.

BP2

BP2 (Not Applied)

According to standard ACMG guidelines, the rule for BP2 is: 'Observed in cis or trans with a pathogenic variant in the same gene'. The evidence for this variant shows: no phase data available. Therefore, BP2 is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, the rule for BP3 is: 'In-frame indel in repetitive region'. The evidence for this variant shows: it is a frameshift, not an in-frame indel. Therefore, BP3 is not applied.

BP4

BP4 (Not Applied)

According to VCEP guidelines, the rule for BP4 is: 'Supporting Strength: two of three splicing tools predict no impact for synonymous or non-coding variants'. The evidence for this variant shows: it is a frameshift coding variant. Therefore, BP4 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 diagnosis. Therefore, BP5 is not applied.

BP6

BP6 (Not Applied)

According to standard ACMG guidelines, the rule for BP6 is: 'Reputable source reports variant as benign without available evidence'. The evidence for this variant shows: no such report. Therefore, BP6 is not applied.

BP7

BP7 (Not Applied)

According to standard ACMG guidelines, the rule for BP7 is: 'Synonymous variant with no splice impact and low conservation'. The evidence for this variant shows: it is not synonymous. Therefore, BP7 is not applied.