ASXL1 c.2562del, p.Asp855IlefsTer12

NM_015338.5:c.2562del
COSM1315841

Classification Summary

Pathogenic

The ASXL1 NM_015338.5:c.2562delT variant leads to a truncating frameshift (PVS1 Very Strong), has supportive functional evidence in murine models (PS3 Strong), and is absent from population controls (PM2 Moderate), with computational evidence against impact (BP4 Supporting). The combination of PVS1, PS3, and PM2 meets criteria for a Pathogenic classification.

Population Frequency
0.0 in 100,000
Rare
ClinVar Classification
Unknown
0 publications
REVEL Score
N/A
Not Available
COSMIC Recurrence
3 occurrences
No Criteria Applied
Classification Evidence
Very Strong (PVS)
PVS1
Strong (PS/BS)
PS3
Moderate (PM/BA)
PM2
Supporting (PP/BP)
BP4
Created: 2025-04-28T12:34:08.458147

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.2562del
Protein Change
D855Ifs*12
Location
Exon 13 (Exon 13 of 13)
13
5' Exon Structure (13 total) 3'
Functional Consequence
Loss of Function
Related Variants
No evidence of other pathogenic variants at position 855 in gene ASXL1
Alternate Identifiers
COSM1315841
Variant interpretation based on transcript NM_015338.6

Clinical Evidence

Population Frequency
Global Frequency
0.0 in 100,000
Extremely Rare
Global: 0.0%
0%
0.0005%
0.001%
0.01%
0.05%
1%+
ACMG Criteria Applied
PM2
This variant is not present in gnomAD (PM2 criteria applies).
ClinVar 2025-04-28T12:32:26.276753
Classification
Unknown
Publications
0 publications
Clinical Statement
COSMIC
COSMIC ID
COSM1315841
Recurrence
3 occurrences
PM1 Criteria
Not Applied
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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 855 in gene ASXL1

Functional Studies

Functional Impact
Summary
The ASXL1 D855Ifs*12 variant is a truncating mutation in a tumor suppressor gene, leading to the loss of the PHD domain. Functional studies have shown that ASXL1 truncating mutations can result in dedifferentiation and myelodysplastic syndrome in murine models, supporting a damaging effect.

Computational Evidence

Pathogenicity Predictions
Predictor Consensus
Mixed/VUS
PP3 Applied
No
Additional Predictors
Benign:
CADD: 3.17
SpliceAI Scores Window: ±500bp
Effect Type Score Position
- Acceptor Loss
0.0
-108 bp
- Donor Loss
0.0
425 bp
+ Acceptor Gain
0.0
121 bp
+ Donor Gain
0.0
157 bp
High impact (≥0.5)
Medium impact (0.2-0.49)
Low impact (<0.2)

VCEP Guidelines

Applied ACMG/AMP Criteria
PVS1
PVS1 (Very Strong)
According to standard ACMG guidelines, the rule for PVS1 is: 'PVS1 – 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: a frameshift deletion NM_015338.5:c.2562delT leading to D855Ifs*12 in ASXL1, a gene where LoF is a known disease mechanism, not in the last exon. Therefore, this criterion is applied at Very Strong strength because it is a null variant in a LoF gene.
PS1
PS1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS1 is: 'PS1 – Same amino acid change as a known pathogenic variant but different nucleotide change'. The evidence for this variant shows: there is no known pathogenic variant at the same residue with a different nucleotide change. Therefore, this criterion is not applied.
PS2
PS2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS2 is: 'PS2 – De novo (both maternity and paternity confirmed) in a patient with the disease and no family history'. The evidence for this variant shows: no information on de novo occurrence is available. Therefore, this criterion is not applied.
PS3
PS3 (Strong)
According to standard ACMG guidelines, the rule for PS3 is: 'PS3 – Well-established functional studies supportive of a damaging effect on the gene or gene product'. The evidence for this variant shows: functional in vivo murine models demonstrate ASXL1 truncating mutations result in dedifferentiation and myelodysplastic syndrome, indicating a damaging effect. Therefore, this criterion is applied at Strong strength because these studies directly support a damaging effect.
PS4
PS4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PS4 is: 'PS4 – Prevalence in affected individuals significantly increased compared with controls'. The evidence for this variant shows: no case-control prevalence data is available. Therefore, this criterion is not applied.
PM1
PM1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM1 is: 'PM1 – Located in a mutational hot spot or well-established functional domain without benign variation'. The evidence for this variant shows: the variant is a frameshift deletion leading to truncation, not specifically located in a hot spot or defined functional domain that meets PM1 criteria. Therefore, this criterion is not applied.
PM2
PM2 (Moderate)
According to standard ACMG guidelines, the rule for PM2 is: 'PM2 – Absent from controls (or at extremely low frequency if recessive)'. The evidence for this variant shows: MAF = 0% in gnomAD and other population databases. Therefore, this criterion is applied at Moderate strength because the variant is absent from population controls.
PM3
PM3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM3 is: 'PM3 – Detected in trans with a pathogenic variant (for recessive disorders)'. The evidence for this variant shows: no data on trans occurrence 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: 'PM4 – Protein length changes due to in-frame deletions/insertions or stop-loss variants'. The evidence for this variant shows: it is a frameshift deletion leading to a stop-gain, 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: 'PM5 – 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 not a missense change at this residue. Therefore, this criterion is not applied.
PM6
PM6 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PM6 is: 'PM6 – Assumed de novo, but without confirmation of paternity and maternity'. The evidence for this variant shows: no de novo assumption 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: 'PP1 – Co-segregation with disease in multiple affected family members'. The evidence for this variant shows: no family 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: 'PP2 – 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 frameshift 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: 'PP3 – Multiple lines of computational evidence support a deleterious effect on the gene or gene product'. The evidence for this variant shows: computational evidence (CADD score 3.17, SpliceAI scores 0) indicates no deleterious impact. Therefore, this criterion is not applied.
PP4
PP4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP4 is: 'PP4 – Patient's phenotype or family history highly specific for a disease with a single genetic etiology'. The evidence for this variant shows: no specific phenotype or family history information is provided. Therefore, this criterion is not applied.
PP5
PP5 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP5 is: 'PP5 – Reputable source reports variant as pathogenic, but without accessible evidence'. The evidence for this variant shows: it is not reported in ClinVar or other databases. Therefore, this criterion is not applied.
BA1
BA1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BA1 is: 'BA1 – Allele frequency is too high for the disorder'. The evidence for this variant shows: allele frequency is 0%. Therefore, this criterion is not applied.
BS1
BS1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS1 is: 'BS1 – Allele frequency is greater than expected for the disorder'. The evidence for this variant shows: allele frequency is 0%. Therefore, this criterion is not applied.
BS2
BS2 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS2 is: 'BS2 – Observed in healthy individuals with full penetrance expected at an early age'. The evidence for this variant shows: no observations in healthy individuals. Therefore, this criterion is not applied.
BS3
BS3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BS3 is: 'BS3 – 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: 'BS4 – Lack of segregation in affected family members'. The evidence for this variant shows: no segregation data are available. Therefore, this criterion is not applied.
BP1
BP1 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP1 is: 'BP1 – Missense variant in a gene where only LoF causes disease'. The evidence for this variant shows: it is 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: 'BP2 – 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 observations. Therefore, this criterion is not applied.
BP3
BP3 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP3 is: 'BP3 – In-frame deletions/insertions in a repetitive region without known function'. The evidence for this variant shows: it is a frameshift deletion, not in-frame or in a repetitive region. Therefore, this criterion is not applied.
BP4
BP4 (Supporting)
According to standard ACMG guidelines, the rule for BP4 is: 'BP4 – Multiple lines of computational evidence suggest no impact on the gene or gene product'. The evidence for this variant shows: CADD score of 3.17 (below threshold) and SpliceAI scores of 0, indicating no predicted impact. Therefore, this criterion is applied at Supporting strength because computational analyses predict no impact.
BP5
BP5 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP5 is: 'BP5 – Variant found in a case with an alternate molecular basis for disease'. The evidence for this variant shows: no alternate molecular basis reported. Therefore, this criterion is not applied.
BP6
BP6 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for BP6 is: 'BP6 – Reputable source reports variant as benign 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: 'BP7 – Synonymous variant with no predicted impact on splicing'. The evidence for this variant shows: it is not synonymous. Therefore, this criterion is not applied.