ASXL1 c.2966_2967del, p.Ser989Ter
NM_015338.5:c.2966_2967del
COSMIC ID: COSM7409983
Pathogenic
This ASXL1 c.2966_2967del (S989*) variant is classified as Pathogenic based on PVS1 (Very Strong), PS3 (Strong), and PM2 (Moderate). Computational evidence (BP4) is supportive of no splicing impact but is outweighed by truncating mutation evidence.
ACMG/AMP Criteria Applied
PVS1
PS3
PM2
BP4
Genetic Information
Gene & Transcript Details
Gene
ASXL1
Transcript
NM_015338.6
MANE Select
Total Exons
13
Strand
Forward (+)
Reference Sequence
NC_000020.10
Alternative Transcripts
| ID | Status | Details |
|---|---|---|
| NM_015338.5 | RefSeq Select | 13 exons | Forward |
| NM_015338.4 | Alternative | 13 exons | Forward |
| NM_015338.3 | Alternative | 13 exons | Forward |
Variant Details
HGVS Notation
NM_015338.5:c.2966_2967del
Protein Change
S989*
Location
Exon 13
(Exon 13 of 13)
5'Exon Structure (13 total)3'
Functional Consequence
Loss of Function
Related Variants
Alternate Identifiers
COSM7409983
Variant interpretation based on transcript NM_015338.6
Genome Browser
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HGVS InputNM_015338:c.2966_2967del
Active Tracks
ConservationRefSeqClinVargnomAD
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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
Functional Summary
Loss-of-Function
The ASXL1 S989* variant is a truncating mutation that likely results in a loss-of-function effect. Functional studies indicate that ASXL1 truncating mutations, which lead to the loss of the PHD domain, are associated with oncogenic processes in myeloid malignancies. Expression of these mutations in murine models has been shown to cause dedifferentiation and myelodysplastic syndrome, supporting a damaging effect of the variant.
Database Previews
OncoKB
JAX-CKB
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Computational Analysis
Pathogenicity Predictions
Predictor Consensus
Unknown
PP3 Applied
No
VCEP Guidelines
Applied ACMG/AMP Criteria (VCEP Specific)
PVS1
PVS1 (Very Strong)
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)'. The evidence for this variant shows: c.2966_2967del results in a premature stop codon (S989*), a truncating variant in ASXL1 where LoF is established as a disease mechanism. Therefore, this criterion is applied at Very Strong strength because a null variant is present in a gene with known LoF disease mechanism.
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: there is no previously reported pathogenic variant causing the same amino acid change S989*. 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 data on de novo status or parental testing 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: functional studies in murine models demonstrate that ASXL1 truncating mutations lead to dedifferentiation and myelodysplastic syndrome, indicating a damaging effect. Therefore, this criterion is applied at Strong strength because well-established in vivo studies support a deleterious effect.
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 prevalence data are available. 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 and/or critical and well-established functional domain without benign variation'. The evidence for this variant shows: exon and domain location information are unavailable. 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) in Exome Sequencing Project, 1000 Genomes Project, or Exome Aggregation Consortium'. The evidence for this variant shows: 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 cohorts.
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 data on allele phase or trans configuration. 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: c.2966_2967del causes a frameshift leading to a premature stop codon, 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: it is a nonsense variant, 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 assumption or related data. 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 familial segregation data are available. 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: it is a truncating variant, not missense. 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: SpliceAI score of 0.02 indicates minimal impact on splicing. 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 is highly specific for a disease with a single genetic etiology'. The evidence for this variant shows: no phenotype or clinical data are 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: no such report or database entry exists. 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: allele frequency is 0% in population databases. 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: variant is absent in 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 healthy individual observations. 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 demonstrate a damaging 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 data available. 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 LoF causes disease'. The evidence for this variant shows: it is a truncating 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 phasing or co-occurrence 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 a known function'. The evidence for this variant shows: it is a frameshift/nonsense variant. 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 or gene product'. The evidence for this variant shows: SpliceAI maximum score of 0.02 indicates minimal splicing impact. Therefore, this criterion is applied at Supporting strength because computational evidence does not predict a functional 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 benign report exists. 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: it is a nonsense variant. Therefore, this criterion is not applied.