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.2985C>T
Protein Change
A995=
Location
Exon 21 (Exon 21 of )
21
5'Exon Structure3'
Functional Consequence
Loss of Function
Alternate Identifiers

Clinical & Population Data

Population Frequency

gnomAD
Global Frequency
0.0607 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
Uncertain Significance (VUS)
3 publications
Clinical Statement

"This variant has been reported in ClinVar as Benign (3 clinical laboratories) and as Uncertain significance (1 clinical laboratories) and as Likely benign (1 clinical laboratories)."

COSMIC Somatic Evidence

Open
COSMIC ID
COSM9312221
Recurrence
2 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 A995= 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
0.0
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.12 -48 bp
- Donor Loss (DL) 0.0 -190 bp
+ Acceptor Gain (AG) 0.0 50 bp
+ Donor Gain (DG) 0.0 -100 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, PVS1 rule is: "Null variant (nonsense, frameshift, canonical ±1 or 2 splice sites, initiation codon, single 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 synonymous (A995=) and not predicted to affect splice sites at canonical positions. Therefore, this criterion is not applied.

PS1

PS1 (Not Applied)

According to standard ACMG guidelines, PS1 rule is: "Same amino acid change as a previously established pathogenic variant regardless of nucleotide change." The evidence for this variant shows no amino acid change (synonymous), so PS1 is not applied.

PS2

PS2 (Not Applied)

According to VCEP guidelines, PS2 requires confirmed de novo occurrence with maternity and paternity and/or tissue mosaicism evidence. No de novo or mosaicism data are available for this variant. Therefore, PS2 is not applied.

PS3

PS3 (Not Applied)

According to standard ACMG guidelines, PS3 rule is: "Well‐established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product." No functional studies are available for this variant. Therefore, PS3 is not applied.

PS4

PS4 (Not Applied)

According to VCEP guidelines, PS4 requires phenotypic case‐control evidence with point scoring and absence from controls (PM2). No case reports or statistical evidence exist for this variant. Therefore, PS4 is not applied.

PM1

PM1 (Not Applied)

According to VCEP guidelines, PM1 Supporting is: "Residues affecting critical functional domains provided in Table 4 for each gene." This variant is synonymous and does not affect a critical domain. Therefore, PM1 is not applied.

PM2

PM2 (Supporting)

According to VCEP guidelines, PM2 Supporting is: "Absent/rare from controls in an ethnically-matched cohort population sample (≥1)." The evidence for this variant shows a maximum gnomAD MAF of 0.0607% (170/280,120 alleles, 2 homozygotes), which is below common thresholds and qualifies as rare. Therefore, PM2 is applied at Supporting strength.

PM3

PM3 (Not Applied)

According to standard ACMG guidelines, PM3 rule is: "For recessive disorders, detected in trans with a pathogenic variant." No information on trans configuration with another variant is available. Therefore, PM3 is not applied.

PM4

PM4 (Not Applied)

According to standard ACMG guidelines, PM4 rule is: "Protein length changes due to in-frame deletions/insertions." This variant is synonymous and does not change protein length. Therefore, PM4 is not applied.

PM5

PM5 (Not Applied)

According to VCEP guidelines, PM5 Moderate is: "Novel missense change at an amino acid where a different missense change is pathogenic." This variant is synonymous. Therefore, PM5 is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, PM6 rule is: "Assumed de novo, without confirmation of paternity and maternity." No de novo data are available. Therefore, PM6 is not applied.

PP1

PP1 (Not Applied)

According to standard ACMG guidelines, PP1 rule is: "Co-segregation with disease in multiple affected family members." No segregation data are available. Therefore, PP1 is not applied.

PP2

PP2 (Not Applied)

According to VCEP guidelines for PIK3CA, PP2 Supporting is: "Missense constraint z-score >3.09." This variant is synonymous, not missense. Therefore, PP2 is not applied.

PP3

PP3 (Not Applied)

According to standard ACMG guidelines, PP3 rule is: "Multiple lines of computational evidence support a deleterious effect." In silico predictors show predominantly benign results (CADD 0.53, SpliceAI 0.12), so no evidence for deleterious effect. Therefore, PP3 is not applied.

PP4

PP4 (Not Applied)

According to standard ACMG guidelines, PP4 rule is: "Patient’s phenotype or family history highly specific for a disease with a single genetic cause." No phenotype data are provided. Therefore, PP4 is not applied.

PP5

PP5 (Not Applied)

According to standard ACMG guidelines, PP5 rule is: "Reputable source reports variant as pathogenic without evidence." ClinVar reports are conflicting (Benign, Likely Benign, VUS). No single reputable source supports pathogenic. Therefore, PP5 is not applied.

BA1

BA1 (Not Applied)

According to VCEP guidelines, BA1 Stand Alone is: "Allele frequency >0.0926%." The variant MAF is 0.0607%, below the threshold. Therefore, BA1 is not applied.

BS1

BS1 (Not Applied)

According to VCEP guidelines, BS1 Strong is: "Allele frequency >0.0185%." The variant MAF of 0.0607% (0.000607) is below 0.0185 (1.85%). Therefore, BS1 is not applied.

BS2

BS2 (Not Applied)

According to VCEP guidelines, BS2 Strong is: "≥3 homozygotes in gnomAD or ≥3 heterozygous well-phenotyped family members." Only 2 homozygotes are observed. Therefore, BS2 is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, BS3 Strong requires well-established functional studies showing no damaging effect. No such studies exist. Therefore, BS3 is not applied.

BS4

BS4 (Not Applied)

According to standard ACMG guidelines, BS4 rule is: "Lack of segregation in affected members of a family." No segregation data are available. Therefore, BS4 is not applied.

BP1

BP1 (Not Applied)

According to standard ACMG guidelines, BP1 rule is: "Missense variant in a gene where only loss-of-function causes disease." This variant is synonymous. Therefore, BP1 is not applied.

BP2

BP2 (Not Applied)

According to standard ACMG guidelines, BP2 rule is: "Observed in trans with a pathogenic variant (for dominant) or in cis with pathogenic variant." No such data exist. Therefore, BP2 is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, BP3 rule is: "In-frame deletions/insertions in a repetitive region without known function." This variant is synonymous. Therefore, BP3 is not applied.

BP4

BP4 (Supporting)

According to VCEP guidelines, BP4 Supporting is: "For synonymous variants, if two of three splicing tools predict no impact on splicing." SpliceAI predicts minimal impact (0.12), and in silico splicing predictors are concordant for no effect. Therefore, BP4 is applied at Supporting strength.

BP5

BP5 (Not Applied)

According to standard ACMG guidelines, BP5 rule is: "Variant found in a case with an alternate molecular basis for disease." No such evidence exists. Therefore, BP5 is not applied.

BP6

BP6 (Not Applied)

According to standard ACMG guidelines, BP6 rule is: "Reputable source reports variant as benign without evidence." ClinVar submissions are conflicting; no single source meets criteria. Therefore, BP6 is not applied.

BP7

BP7 (Not Applied)

According to VCEP guidelines, BP7 Supporting is: "Synonymous variant at non-conserved nucleotide (PhyloP <0.1)." No conservation data (PhyloP) are provided. Therefore, BP7 is not applied.