ASXL1 c.2226del, p.Leu743Ter
NM_015338.5:c.2226del
Pathogenic
The ASXL1 c.2226delG (L743*) truncating variant is classified as Pathogenic based on Very Strong PVS1 (LoF mechanism), Strong PS3 (functional studies), and Moderate PM2 (absent from controls) 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.2226del
Protein Change
L743*
Location
Exon 13
(Exon 13 of 13)
5'Exon Structure (13 total)3'
Functional Consequence
Loss of Function
Related Variants
Variant interpretation based on transcript NM_015338.6
Genome Browser
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HGVS InputNM_015338:c.2226del
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
The ASXL1 L743* variant is a truncating mutation that results in the loss of the PHD domain, leading to the production of C-terminally truncated proteins. Functional studies have demonstrated that expression of ASXL1 truncating mutations in murine myeloid cells causes dedifferentiation and myelodysplastic syndrome in a bone marrow transplant mouse model, supporting a damaging effect and likely oncogenic role in myeloid malignancies.
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: NM_015338.5:c.2226delG results in a premature stop codon (L743*), predicted to cause loss of function in ASXL1. Therefore, this criterion is applied at Very Strong strength because this is a null variant in a gene where LoF is a known mechanism of disease.
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 known pathogenic variant at the same amino acid position 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: "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 occurrence. Therefore, this criterion is not applied.
PS3
PS3 (Strong)
According to standard ACMG guidelines, the rule for PS3 is: "Well-established in vitro or in vivo functional studies supportive of a damaging effect on the gene or gene product." The evidence for this variant shows: murine bone marrow transplant models expressing ASXL1 truncating mutations including L743* cause myelodysplastic syndrome, supporting a damaging effect. Therefore, this criterion is applied at Strong strength because well-established functional studies demonstrate a damaging effect on ASXL1.
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 data 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 or well-established functional domain without benign variation." The evidence for this variant shows: no specific hot spot or domain evidence beyond general truncation. 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: not found in gnomAD or other population databases (MAF=0%). 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: "Detected in trans with a pathogenic variant for recessive disorders." The evidence for this variant shows: ASXL1 disorders are dominant and no trans data available. 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/nonsense variant, not an in-frame indel. 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: not a missense variant. 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. 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 family 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 low rate of benign missense variation where missense is common mechanism." The evidence for this variant shows: variant is truncating, 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 maximum score 0.01, no predicted impact on splicing or function. Therefore, this criterion is not applied.
PP4
PP4 (Not Applied) Strength Modified
According to standard ACMG guidelines, the rule for PP4 is: "Patient phenotype or family history highly specific for a disease with a single genetic etiology." The evidence for this variant shows: no detailed phenotype 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 without accessible evidence." The evidence for this variant shows: no ClinVar or other reputable report. 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%. 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: 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: "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: "Well-established functional studies show no damaging effect on protein function or splicing." The evidence for this variant shows: functional studies show 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. 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: not missense. 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 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: not an in-frame deletion. 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: SpliceAI maximum score 0.01, minimal predicted impact on splicing. Therefore, this criterion is applied at Supporting strength because computational evidence suggests no impact.
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 such case 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 without accessible evidence." The evidence for this variant shows: no such report. 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: variant is nonsense, not synonymous. Therefore, this criterion is not applied.