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.1943T>G
Protein Change
L648W
Location
Exon 13 (Exon 13 of )
13
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
Recurrence
0 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 PIK3CA L648W variant 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
Mixed/VUS
PP3 Applied
No
REVEL Score
0.203
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.03 -80 bp
- Donor Loss (DL) 0.0 76 bp
+ Acceptor Gain (AG) 0.0 -31 bp
+ Donor Gain (DG) 0.0 72 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 multi-exon deletion) in a gene where loss of function is a known mechanism of disease.' The evidence for this variant shows: it is a missense change (L648W), not a null variant. Therefore, this criterion is not applied because the variant type does not meet the rule for PVS1.

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: no previously established pathogenic variant at codon L648 in PIK3CA. Therefore, this criterion is not applied.

PS2

PS2 (Not Applied)

According to VCEP guidelines, the rule for PS2 is: 'Award the PS2_Strong point if Criteria 1 AND Criteria 2 are fulfilled...' for high-confidence somatic mutations. The evidence for this variant shows: no parental or tissue segregation data are available. Therefore, this criterion is not applied due to lack of de novo or somatic confirmation data.

PS3

PS3 (Not Applied)

According to VCEP guidelines, the rule for PS3 is: 'Functional assays meeting SVI and BMVCEP quality metrics and validation controls...' The evidence for this variant shows: no functional studies have been performed. Therefore, this criterion is not applied due to absence of functional assay data.

PS4

PS4 (Not Applied)

According to VCEP guidelines, the rule for PS4 is: 'Points assigned for phenotype according to Table 2A, applied only if variant is absent from controls.' The evidence for this variant shows: no case reports or phenotype data. Therefore, this criterion is not applied due to lack of case-level evidence.

PM1

PM1 (Not Applied)

According to VCEP guidelines, the rule for PM1 is: 'Supporting: Residues affecting critical functional domains provided in Table 4 for each gene.' The evidence for this variant shows: L648 is not located in a known critical hotspot or domain defined by the VCEP Table 4. Therefore, this criterion is not applied.

PM2

PM2 (Supporting)

According to VCEP guidelines, the rule for PM2 is: '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, this criterion is applied at Supporting strength because the variant is absent from controls.

PM3

PM3 (Not Applied)

According to standard ACMG guidelines, the rule for PM3 is: 'For recessive disorders, detected in trans with a pathogenic variant.' The evidence for this variant shows: PIK3CA disorders are not recessive and no in-trans data exist. 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 indels or stop-loss variants.' The evidence for this variant shows: it is a single amino acid substitution with no length change. Therefore, this criterion is not applied.

PM5

PM5 (Not Applied)

According to VCEP guidelines, the rule for PM5 (Moderate) is: 'Different missense change at an amino acid residue where a pathogenic missense change has been established.' The evidence for this variant shows: no other pathogenic missense change at residue L648 is known. Therefore, this criterion is not applied.

PM6

PM6 (Not Applied)

According to VCEP guidelines, the rule for PM6 is: 'Assumed de novo without confirmation of paternity and 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: 'Co-segregation with disease in multiple affected family members.' The evidence for this variant shows: no segregation data are available. Therefore, this criterion is not applied.

PP2

PP2 (Supporting)

According to VCEP guidelines, the rule for PP2 is: 'Missense constraint computed in ExAC/gnomAD; award PP2 if the z-score > 3.09 (applicable to PIK3CA).' The evidence for this variant shows: PIK3CA has a missense z-score > 3.09, and this is a missense change. 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.' The evidence for this variant shows: in silico predictions are mixed with a predominance of benign scores. 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 data are available. 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.' The evidence for this variant shows: no such reports exist in ClinVar or other databases. Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to VCEP guidelines, the rule for BA1 (Stand Alone) is: 'Allele frequency > 0.0926%.' The evidence for this variant shows: MAF = 0% in population databases. Therefore, this criterion is not applied.

BS1

BS1 (Not Applied)

According to VCEP guidelines, the rule for BS1 (Strong) is: 'Allele frequency > 0.0185%.' The evidence for this variant shows: MAF = 0% in population databases. Therefore, this criterion is not applied.

BS2

BS2 (Not Applied)

According to VCEP guidelines, the rule for BS2 (Strong) is: '≥ 3 homozygotes in gnomAD or ≥ 3 heterozygotes in well-phenotyped family members.' The evidence for this variant shows: no observations in homozygous or well-phenotyped heterozygous individuals. Therefore, this criterion is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, the rule for BS3 is: 'Well-validated functional studies show no damaging effect.' The evidence for this variant shows: no functional studies. 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 segregation 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 where only loss-of-function causes disease.' The evidence for this variant shows: PIK3CA disease mechanism is gain-of-function. Therefore, this criterion is not applied.

BP2

BP2 (Not Applied)

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

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, the rule for BP3 is: 'In-frame indels in repetitive regions without a known function.' The evidence for this variant shows: this is a single amino acid substitution outside repeat regions. Therefore, this criterion is not applied.

BP4

BP4 (Not Applied)

According to VCEP guidelines, the rule for BP4 is: 'Applicable only to synonymous or non-coding variants when splicing prediction tools predict no impact.' The evidence for this variant shows: it is a missense change. 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 case data. 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.' The evidence for this variant shows: no such reports exist. Therefore, this criterion is not applied.

BP7

BP7 (Not Applied)

According to VCEP guidelines, the rule for BP7 is: 'Applicable only to synonymous or intronic variants with low conservation.' The evidence for this variant shows: it is a missense change. Therefore, this criterion is not applied.