Genetic Information
Gene & Transcript Details
| ID | Status | Details |
|---|---|---|
| NM_015338.6 | MANE Select | 7052 nt | 446–5071 |
| NM_015338.5 | RefSeq Select | 7056 nt | 433–5058 |
| NM_015338.4 | Alternative | 7047 nt | 427–5052 |
| NM_015338.3 | Alternative | 7026 nt | 420–5045 |
Variant Details
Clinical & Population Data
Population Frequency
gnomADClinVar
Open""
COSMIC Somatic Evidence
Open
Functional Impact & Domains
Functional Domain
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.
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Computational Analysis
Pathogenicity Predictions
SpliceAISpliceAI Scores
Window: ±500bp| Effect Type | Score | Position |
|---|---|---|
| Acceptor Loss (AL) | 0.0 | -31 bp |
| Donor Loss (DL) | 0.02 | 23 bp |
| Acceptor Gain (AG) | 0.0 | -187 bp |
| Donor Gain (DG) | 0.02 | 172 bp |
VCEP Guidelines
Applied ACMG/AMP Criteria (VCEP Specific)
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 (Not Applied)
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 (Not Applied)
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 (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 (Not Applied)
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 (Not Applied)
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 (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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (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 familial segregation data are available. Therefore, this criterion is not applied.
PP2 (Not Applied)
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 (Not Applied)
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 (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 or clinical data are provided. Therefore, this criterion is not applied.
PP5 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (Not Applied)
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 (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 (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 alternate molecular diagnosis reported. Therefore, this criterion is not applied.
BP6 (Not Applied)
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 (Not Applied)
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.