PPM1D c.1446del, p.Thr483LeufsTer2
NM_003620.3:c.1446del
Pathogenic
The PPM1D c.1446delG (p.T483Lfs*2) variant is absent from population databases and supported by strong functional data demonstrating oncogenic gain-of-function. Loss-of-function is not the disease mechanism, so PVS1 is not applied. PS3 (Strong) and PM2 (Moderate) are applied with BP4 (Supporting), yielding a Likely Pathogenic classification under ACMG criteria.
ACMG/AMP Criteria Applied
PS3
PM2
BP4
Genetic Information
Gene & Transcript Details
Gene
PPM1D
Transcript
NM_003620.4
MANE Select
Total Exons
6
Strand
Forward (+)
Reference Sequence
NC_000017.10
Alternative Transcripts
| ID | Status | Details |
|---|---|---|
| NM_003620.3 | RefSeq Select | 6 exons | Forward |
| NM_003620.2 | Alternative | 6 exons | Forward |
Variant Details
HGVS Notation
NM_003620.3:c.1446del
Protein Change
T483Lfs*2
Location
Exon 6
(Exon 6 of 6)
5'Exon Structure (6 total)3'
Functional Consequence
Loss of Function
Related Variants
No evidence of other pathogenic variants at position 483 in gene PPM1D
Variant interpretation based on transcript NM_003620.4
Genome Browser
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HGVS InputNM_003620:c.1446del
Active Tracks
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Clinical Data
Population Frequency
Global Frequency
0.0 in 100,000
Extremely Rare
Global: 0.0%
0%
0.05%
0.1%
1%
5%
10%+
ACMG Criteria Applied
PM2
This variant is not present in gnomAD (PM2 criteria applies).
Classification
Unknown
Publications (0)
No publication details.
Clinical Statement
Functional Impact
Functional Domain
Hotspot Status
Not a hotspot
Domain Summary
This variant is not located in a mutational hotspot or critical domain (0 mutations).
Related Variants in This Domain
No evidence of other pathogenic variants at position 483 in gene PPM1D
Functional Summary
Gain-of-Function
The PPM1D T483Lfs*2 variant is functionally characterized as likely oncogenic. Truncating mutations in the C-terminal portion of PPM1D, including this variant, confer gain-of-function activity. These mutations result in increased protein stability, attenuated activation of DNA damage response mediators, and enhanced cell growth and colony formation. In vivo studies demonstrate that such mutations are activating, leading to increased development of acute myeloid leukemia. Additionally, PPM1D truncating mutations confer resistance to chemotherapeutic agents but show sensitivity to a specific allosteric inhibitor.
Database Previews
OncoKB
JAX-CKB
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Computational Analysis
Pathogenicity Predictions
Predictor Consensus
Mixed/VUS
PP3 Applied
No
Additional Predictors
Benign:
CADD: 4.89
VCEP Guidelines
Applied ACMG/AMP Criteria (VCEP Specific)
PVS1
PVS1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PVS1 is: "Null variant in a gene where loss of function (LoF) is a known mechanism of disease (e.g., nonsense, frameshift, canonical ±1 or 2 splice sites, initiation codon, single exon deletion in a LoF gene)". The evidence for this variant shows: PPM1D C-terminal truncating variants act via gain-of-function rather than loss-of-function. Therefore, this criterion is not applied because loss of function is not the established mechanism of disease for PPM1D.
PS1
PS1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS1 is: "Same amino acid change as a known pathogenic variant but different nucleotide change". The evidence for this variant shows: no other pathogenic variant with the exact p.T483Lfs*2 amino acid change has been reported. Therefore, this criterion is not applied.
PS2
PS2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS2 is: "De novo (both maternity and paternity confirmed) in a patient with the disease and no family history". The evidence for this variant shows: no de novo or parental testing data are available. Therefore, this criterion is not applied.
PS3
PS3 (Strong)
According to standard ACMG 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: in vitro and in vivo studies demonstrate that PPM1D T483Lfs*2 confers gain-of-function oncogenic activity, increased stability, altered DNA damage response, leukemogenic potential, and altered drug sensitivity. Therefore, this criterion is applied at Strong strength because multiple well-established functional studies show a damaging (oncogenic) effect consistent with disease mechanism.
PS4
PS4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS4 is: "Prevalence in affected individuals significantly increased compared with controls". The evidence for this variant shows: no case–control or cohort data demonstrating increased prevalence in affected individuals. Therefore, this criterion is not applied.
PM1
PM1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM1 is: "Located in a mutational hot spot or well-established functional domain without benign variation". The evidence for this variant shows: although C-terminal truncations cluster, no specific hot spot or domain rule is established for PPM1D. Therefore, this criterion is not applied.
PM2
PM2 (Moderate)
According to standard ACMG guidelines, the rule for PM2 is: "Absent from controls (or at extremely low frequency if recessive)". The evidence for this variant shows: the variant is not present in gnomAD or other population databases (MAF=0%). Therefore, this criterion is applied at Moderate strength because the variant is absent from large population datasets.
PM3
PM3 (Not Applied) Strength Modified
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: no information on trans configuration or zygosity with another variant. Therefore, this criterion is not applied.
PM4
PM4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM4 is: "Protein length changes due to in-frame deletions/insertions or stop-loss variants". The evidence for this variant shows: this is a frameshift leading to truncation, not an in-frame change. Therefore, this criterion is not applied.
PM5
PM5 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM5 is: "Novel missense change at an amino acid residue where a different pathogenic missense change has been seen". The evidence for this variant shows: p.T483Lfs*2 is not a missense change. Therefore, this criterion is not applied.
PM6
PM6 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM6 is: "Assumed de novo, but without confirmation of paternity and maternity". The evidence for this variant shows: no de novo data are available. Therefore, this criterion is not applied.
PP1
PP1 (Not Applied) Strength Modified
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, this criterion is not applied.
PP2
PP2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP2 is: "Missense variant in a gene with a low rate of benign missense variation and where missense variants are a common mechanism of disease". The evidence for this variant shows: this is not a missense variant. Therefore, this criterion is not applied.
PP3
PP3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP3 is: "Multiple lines of computational evidence support a deleterious effect on the gene/gene product". The evidence for this variant shows: CADD score of 4.89 suggests low impact and SpliceAI scores of 0 predict no splicing alteration. Therefore, this criterion is not applied.
PP4
PP4 (Not Applied) Strength Modified
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 specificity or single-etiology data provided. Therefore, this criterion is not applied.
PP5
PP5 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP5 is: "Reputable source reports variant as pathogenic, but without accessible evidence". The evidence for this variant shows: not reported in ClinVar or other authoritative databases. Therefore, this criterion is not applied.
BA1
BA1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BA1 is: "Allele frequency is too high for the disorder". The evidence for this variant shows: absent from population databases, not exceeding frequency thresholds. Therefore, this criterion is not applied.
BS1
BS1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS1 is: "Allele frequency is greater than expected for the disorder". The evidence for this variant shows: absent from population databases. Therefore, this criterion is not applied.
BS2
BS2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS2 is: "Observed in healthy individuals with full penetrance expected at an early age". The evidence for this variant shows: no such observations reported. Therefore, this criterion is not applied.
BS3
BS3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS3 is: "Well-established functional studies show no damaging effect on protein function or splicing". The evidence for this variant shows: functional studies indicate a damaging gain-of-function effect. Therefore, this criterion is not applied.
BS4
BS4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS4 is: "Lack of segregation in affected family members". The evidence for this variant shows: no segregation studies. Therefore, this criterion is not applied.
BP1
BP1 (Not Applied) Strength Modified
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: not a missense variant. Therefore, this criterion is not applied.
BP2
BP2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP2 is: "Observed in trans with a pathogenic variant for dominant disorders or in cis with a pathogenic variant". The evidence for this variant shows: no such allelic data. Therefore, this criterion is not applied.
BP3
BP3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP3 is: "In-frame deletions/insertions in a repetitive region without known function". The evidence for this variant shows: frameshift, not in-frame. Therefore, this criterion is not applied.
BP4
BP4 (Supporting)
According to standard ACMG guidelines, the rule for BP4 is: "Multiple lines of computational evidence suggest no impact on gene/gene product". The evidence for this variant shows: CADD score of 4.89 and SpliceAI scores of 0 indicating no predicted deleterious effect. Therefore, this criterion is applied at Supporting strength because multiple in silico tools predict a benign effect.
BP5
BP5 (Not Applied) Strength Modified
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 molecular diagnosis reported. Therefore, this criterion is not applied.
BP6
BP6 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP6 is: "Reputable source reports variant as benign, but without accessible evidence". The evidence for this variant shows: no such reports. Therefore, this criterion is not applied.
BP7
BP7 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP7 is: "Synonymous variant with no predicted impact on splicing". The evidence for this variant shows: not a synonymous change. Therefore, this criterion is not applied.