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NM_000314.8:c.888T>A
p.Cys296Ter · PTEN
0%
complete
Final classification
Likely Pathogenic
PVS1PM2
PTEN
c.888T>A
p.Cys296Ter
stop gained

PTEN is a tumor suppressor gene that encodes a phosphatase converting the lipid messenger PIP3 back to PIP2 at the cell membrane, thereby restraining the AKT/mTOR signaling pathway that drives cell growth, proliferation, and survival. It is one of the most frequently mutated genes across many types of human cancer, and its loss promotes unchecked cell growth, survival, and genomic instability, partly through impaired DNA repair. Germline loss-of-function variants in PTEN cause Cowden syndrome, an inherited cancer predisposition disorder associated with elevated risk of breast and thyroid cancer.

This variant

PTEN is a tumor suppressor that restrains the AKT/mTOR growth pathway, and germline loss-of-function variants cause Cowden syndrome with elevated breast and thyroid cancer risk. This nonsense variant truncates the PTEN protein (~26.6% removed) and is predicted to undergo nonsense-mediated decay, indicating loss of PTEN function; the Likely Pathogenic classification means it is expected to predispose to Cowden syndrome and its associated cancers.

Transcript
NM_000314.8
HGVS · transcript:coding
NM_000314.8:c.888T>A
GRCh38
chr10:87960980 T>A
GRCh37
chr10:89720737 T>A
Under ClinGen PTEN EP v3.2, PVS1 (Very Strong: nonsense p.Cys296Ter predicted NMD) + PM2 (Supporting: absent from gnomAD) satisfies Rule20, mapping to Likely Pathogenic with no conflicting evidence.
Classification rationale
PVS1PM2 Likely Pathogenic
PTEN c.888T>A stop gained

PVS1 (Very Strong): nonsense p.Cys296Ter — stop codon at 296, 5' to p.D375, predicted to trigger nonsense-mediated decay. PM2 (Supporting): absent from gnomAD v2.1, v4.1, and gnomAD-Canada (allele frequency 0). Overall: Likely Pathogenic under ClinGen PTEN EP v3.2 Rule20 (1 Pathogenic Very Strong + 1 Pathogenic Supporting).

PVS1 + PM2 → Likely Pathogenic
LYFE Sciences is an AI system, and it can make mistakes. Criteria may be applied incorrectly, sources may be misread, and a confident-looking classification can still be wrong. Double-check every criterion and its underlying evidence before relying on any call.
Gene diagram · NM_000314.8 · variants mapped to exon structure
PTEN NM_000314.8
Fetching transcript structure from UCSC…
Applied criteria · 2 applied · 15 assessed
MetEvidence satisfies this criterion.
Not metEvaluated against available evidence; threshold not reached.
Not assessedApplies in principle, but no evidence was found to evaluate it.
N/ADoesn't apply to this variant type.
Applied · 2
Strength Supporting Moderate Strong Very strong
PVS1 very strong Pathogenic
Met: nonsense p.Cys296Ter — stop codon 296 lies 5' of p.D375/c.1121, predicted to trigger nonsense-mediated decay, satisfying the PTEN PVS1 tree at very strong strength.
PTEN VCEP PVS1 decision tree (vcep_pvs1_decisiontree_pten, index.txt): nonsense/frameshift with stop codon or disruption at or 5' to p.D375 (c.1121), exon present in biologically-relevant transcript NM_000314.8 and predicted to undergo NMD -> PVS1; stop codon 3' to p.D375 not predicted to undergo NMD -> PVS1_ModerateClinGen PTEN EP CSPEC v3.2 PVS1 rule (cspec): 'Use PTEN PVS1 decision tree'; defaultStrength Pathogenic Very Strongprefetch normalization (Mutalyzer): NM_000314.8:c.888T>A -> NP_000305.3:p.(Cys296Ter); predicted protein MTAII...ENGSL* (296 aa) vs wild-type 403 aa
PM2 supporting Pathogenic
Met: allele frequency 0 — absent from gnomAD v2.1, v4.1, and gnomAD-Canada, below the <0.00001 threshold; supporting strength.
gnomAD v2.1 (exome, GRCh37) variant page for 10-89720737-T-A: search_status 'absent', found=false — evidence_sentence 'Absent from gnomAD v2.1.'; screenshot gnomad_v2.png captured (manifest ok=true).gnomAD v4.1 (exome, GRCh38) variant page for 10-87960980-T-A: search_status 'absent', found=false — evidence_sentence 'Absent from gnomAD v4.1.'; screenshot gnomad_v4.png captured (manifest ok=true).gnomAD-Canada v1.0 (HostSeq genomes) API for 10-87960980-T-A: search_status 'absent', found=false — evidence_sentence 'Absent from gnomAD-Canada v1.0.'
Assessed · not applied · 8 not met · 7 not assessed
Pathogenic
PS1 Not met: no alternate nucleotide change at codon 296 produces p.Cys296Ter, and none is previously established as pathogenic.
PS2 Not assessed: no parental testing, de novo observation, or family-history data exist for c.888T>A; ClinVar submissions lack inheritance details.
PS3 Not met: no RNA, mini-gene, or functional assay of c.888T>A exists; the VCEP assay table covers missense variants only.
PS4 Not assessed: no proband phenotype scores or case-control study data exist for c.888T>A; ClinVar carries only submission-level condition labels.
PM1 Not met: p.Cys296 lies outside the PTEN-defined catalytic motifs (residues 90-94, 123-130, 166-168).
PM4 Not met: the variant is a truncating nonsense change, not an in-frame indel or stop-loss extension, so PM4 does not apply to this consequence class.
PM6 Not assessed: no assumed or presumed de novo observation of c.888T>A is documented, and no family-history data are available.
PP1 Not assessed: zero documented meioses — no segregation study or pedigree involving c.888T>A exists in the available literature.
Benign
BA1 Not met: allele frequency 0, far below the gnomAD BA1 threshold of 0.00056.
BS1 Not met: allele frequency 0 is below the lowest BS1 supporting-tier threshold of 0.0000043.
BS2 Not met: zero homozygous or heterozygous observations in any population cohort; no healthy or unaffected homozygote data.
BS3 Not met: no functional evidence of normal protein function exists; the VCEP assay covers missense variants only.
BS4 Not assessed: no documented non-segregation observation for c.888T>A; absence of segregation data cannot establish lack of segregation.
BP2 Not assessed: no trans/cis phase data — no second PTEN variant, parental testing, or phase information is documented for c.888T>A.
BP5 Not assessed: no carrier-level clinical data — no alternate molecular cause or phenotype-overlap history is documented for c.888T>A.
N/A · 11 PM3 · PM5 · PP2 · PP3 · PP4 · PP5 · BP1 · BP3 · BP4 · BP6 · BP7
Research & evidence
Population frequency · supports pathogenic
gnomAD v4.1 screenshot
gnomAD v4.1
gnomAD v2.1 screenshot
gnomAD v2.1
v4.1
Absent from gnomAD v4.1.
v2.1
Absent from gnomAD v2.1.
🇨🇦 CA
Absent from gnomAD-Canada v1.0.
Allele frequency by ancestry
three datasets · side by side
gnomAD v4.1
Absent · 0 / ?
0 hom
Not observed in any ancestry group.
gnomAD v2.1
Absent · 0 / ?
0 hom
Not observed in any ancestry group.
gnomAD Canada 🇨🇦
Absent · 0 / ?
0 hom
Not observed in any ancestry group.
ClinVar screenshot
ClinVar
This variant has been reported in ClinVar as Pathogenic (2 clinical laboratories) and as Likely pathogenic (1 clinical laboratory). (ClinVarID = 917617)
SpliceAI screenshot
In silico
SpliceAI predicts no significant splice impact for this variant (max delta score = 0.00). BayesDel score = 0.60222.
Functional / OncoKB screenshot
Functional Likely Oncogenic
OncoKB identified variant-specific curated literature and context relevant to functional review; biological-effect context: Likely Loss-of-function; curated oncogenicity label: Likely Oncogenic.
OncoKB ↗
COSMIC screenshot
COSMIC
Cancer hotspots screenshot
Cancer hotspots
Somatic evidence Not in COSMIC / hotspots
COSMIC
This variant does not lie in a statistically significant hotspot. This variant has not previously been reported in somatic cancers (COSMIC).
Hotspots
This variant does not lie in a statistically significant hotspot.
Sources & reference links
9Sources
CSpec VCEP
ClinVar
gnomAD v2.1
gnomAD v4.1
gnomAD-Canada
SpliceAI
OncoKB
COSMIC
Cancer hotspots
Triaged references · 8 PMIDs not cited in assessment
11237521 ↗ PTEN: life as a tumor suppressor. ONCOKB
17218262 ↗ Essential role for nuclear PTEN in maintaining chromosomal integrity. ONCOKB
20301661 ↗ PTEN Hamartoma Tumor Syndrome. CLINVAR
25394175 ↗ A practice guideline from the American College of Medical Genetics and Genomics and the National Society of Genetic Counselors: referral indications for cancer predisposition assessment. CLINVAR
26389210 ↗ Genetics of Breast and Gynecologic Cancers (PDQ®): Health Professional Version. CLINVAR
26389333 ↗ Genetics of Skin Cancer (PDQ®): Health Professional Version. CLINVAR
26492180 ↗ Molecular Analysis of Mixed Endometrial Carcinomas Shows Clonality in Most Cases. CLINVAR
27324988 ↗ A Pilot Study of Clinical Targeted Next Generation Sequencing for Prostate Cancer: Consequences for Treatment and Genetic Counseling. CLINVAR