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

""

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 has not been functionally characterized.

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 (Not Applied)

According to standard ACMG guidelines, the rule for PVS1 is: "Null variant (nonsense, frameshift, canonical ±1 or 2 splice sites, initiation codon, single exon or multiexon deletion) in a gene where loss‐of‐function is a known mechanism of disease." The evidence for this variant shows: c.1265del (L422Wfs*6) is a frameshift but PIK3CA is not established to cause disease by loss‐of‐function. Therefore, this criterion is not applied.

PS1

PS1 (Not Applied)

According to VCEP guidelines, the rule for PS1 is: "Same amino acid change as a previously established pathogenic variant regardless of nucleotide change." The evidence for this variant shows: L422Wfs*6 is a novel frameshift, not a previously observed missense or nonsense at the same codon. Therefore, this criterion is not applied.

PS2

PS2 (Not Applied)

According to VCEP guidelines, the rule for PS2_Strong is: "Variant is present in affected tissue and absent from parental samples with confirmed maternity/paternity." The evidence for this variant shows: no de novo or somatic mosaic data are provided. Therefore, this criterion is not applied.

PS3

PS3 (Not Applied)

According to VCEP 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: no functional assays have been reported for L422Wfs*6. Therefore, this criterion is not applied.

PS4

PS4 (Not Applied)

According to VCEP guidelines, the rule for PS4 is: "Increased prevalence in affected individuals compared with controls." The evidence for this variant shows: no case reports or segregation data. Therefore, this criterion is not applied.

PM1

PM1 (Not Applied)

According to VCEP guidelines, the rule for PM1 is: "Located in a mutational hot spot or well‐studied functional domain without benign variation." The evidence for this variant shows: L422Wfs*6 is outside well‐characterized somatic hotspot codons (e.g., 542, 545, 1047). Therefore, this criterion is not applied.

PM2

PM2 (Supporting)

According to VCEP guidelines, the rule for PM2 is: "Supporting Absent/rare from controls in an ethnically‐matched cohort population sample (≥1)." The evidence for this variant shows: c.1265del (L422Wfs*6) is absent from gnomAD (MAF = 0%). Therefore, this criterion 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 recessive disorders." The evidence for this variant shows: PIK3CA‐related conditions are not autosomal recessive and no trans observations. 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 in non‐repeat regions or stop‐loss." The evidence for this variant shows: L422Wfs*6 is a frameshift leading to premature stop, which is addressed by PVS1 (not applied here). 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 missense change is pathogenic." The evidence for this variant shows: L422Wfs*6 is a frameshift, not a missense. 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/maternity." The evidence for this variant shows: no de novo data. Therefore, this criterion is not applied.

PP1

PP1 (Not Applied)

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

PP2

PP2 (Not Applied)

According to VCEP guidelines, the rule for PP2 is: "Missense constraint (z‐score > 3.09) in genes where missense variants are common mechanism." The evidence for this variant shows: it is a frameshift, not missense. Therefore, this criterion is not applied.

PP3

PP3 (Not Applied)

According to standard ACMG guidelines, the rule for PP3 is: "Multiple lines of computational evidence support a deleterious effect." The evidence for this variant shows: SpliceAI score 0.07, low predicted impact; no in silico evidence of deleterious effect beyond the frameshift. 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 is highly specific for a disease with a single genetic etiology." The evidence for this variant shows: no phenotype or clinical presentation 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 without available evidence." The evidence for this variant shows: not reported in ClinVar or other databases. Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to VCEP guidelines, the rule for BA1 is: "Allele frequency > 0.0926% (Stand-Alone Benign)." The evidence for this variant shows: absent from population databases. Therefore, this criterion is not applied.

BS1

BS1 (Not Applied)

According to VCEP guidelines, the rule for BS1 is: "Allele frequency > 0.0185% (Strong Benign)." The evidence for this variant shows: absent from population databases. Therefore, this criterion is not applied.

BS2

BS2 (Not Applied)

According to VCEP guidelines, the rule for BS2 is: "Observed in ≥3 healthy homozygotes or heterozygotes with no disease." The evidence for this variant shows: no such observations. Therefore, this criterion is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, the rule for BS3 is: "Well-established functional studies show no damaging effect." The evidence for this variant shows: no functional studies available. 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 members of a family." The evidence for this variant shows: no family data. 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 for which primarily truncating variants cause disease." The evidence for this variant shows: this is a truncating variant and PIK3CA disease is caused by gain-of-function missense, not relevant. 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 in a dominant gene." 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 repetitive regions without a known function." The evidence for this variant shows: frameshift outside repetitive region. Therefore, this criterion is not applied.

BP4

BP4 (Not Applied)

According to VCEP guidelines, the rule for BP4 is: "Synonymous or noncoding variants with no predicted splicing impact by ≥2 tools." The evidence for this variant shows: this is a frameshift, not synonymous or noncoding. 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 alternate cause 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 without available evidence." The evidence for this variant shows: not reported benign in any source. 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 splicing impact and nucleotide not conserved." The evidence for this variant shows: not synonymous. Therefore, this criterion is not applied.