Genetic Information
Gene & Transcript Details
| ID | Status | Details |
|---|---|---|
| NM_004343.2 | Alternative | 1899 nt | 69–1322 |
| NM_004343.3 | RefSeq Select | 1929 nt | 81–1334 |
| NM_004343.4 | MANE Select | 1901 nt | 72–1325 |
Variant Details
Clinical & Population Data
Population Frequency
gnomADClinVar
Open""
COSMIC Somatic Evidence
Open
Functional Impact & Domains
Functional Domain
The CALR K385Tfs*47 variant is functionally characterized as likely oncogenic. Truncating and frameshift mutations in CALR, including this variant, are associated with cytokine-independent growth in Ba/F3 cells and are prevalent in myeloproliferative neoplasms lacking MPL or JAK2 mutations. These mutations result in novel, positively-charged C-terminal amino acids and are linked to an increased risk of myelofibrotic transformation.
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Computational Analysis
Pathogenicity Predictions
SpliceAISpliceAI Scores
Window: ±500bp| Effect Type | Score | Position |
|---|---|---|
| Acceptor Loss (AL) | 0.03 | -96 bp |
| Donor Loss (DL) | 0.0 | 175 bp |
| Acceptor Gain (AG) | 0.04 | -70 bp |
| Donor Gain (DG) | 0.0 | -120 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 in a LoF gene)". The evidence for this variant shows: it is a frameshift (K385Tfs*47) creating a premature stop codon in CALR, a gene where LoF is a known disease mechanism in myeloproliferative neoplasms. Therefore, this criterion is applied at Very Strong strength because the variant is a null variant in a gene with a known LoF 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: it is a novel frameshift, not a recapitulation of a known pathogenic amino acid change. Therefore, this criterion is not applied because there is no identical amino acid change reported.
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 parental testing or segregation data are available to confirm de novo status. Therefore, this criterion is not applied due to lack of de novo confirmation.
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 studies demonstrate that CALR K385Tfs*47 induces oncogenic, cytokine‐independent growth and alters the C‐terminal charge, consistent with disease. Therefore, this criterion is applied at Strong strength because well-established functional studies support a damaging 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 formal case‐control or cohort frequency data are available. Therefore, this criterion is not applied due to absence of prevalence data.
PM1 (Moderate)
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: it occurs at codon K385 in exon 9 of CALR, a known hotspot for pathogenic frameshift mutations in myeloproliferative neoplasms. Therefore, this criterion is applied at Moderate strength because the variant lies in a well‐established hotspot.
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: it is not observed in population databases including gnomAD. Therefore, this criterion is applied at Moderate strength because the variant is absent from controls.
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: there is no data on inheritance in trans with another variant. Therefore, this criterion is not applied due to lack of trans‐phase data.
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: it is an out-of-frame insertion/deletion leading to a premature stop, not an in-frame length 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 frameshift, 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 parental data are available. 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 family segregation data are provided. 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 frameshift, not a missense variant. 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 (e.g., conservation, splicing impact)". The evidence for this variant shows: in silico splicing predictions are minimal and the variant is a frameshift. Therefore, this criterion is not applied due to lack of supportive computational data.
PP4 (Not Applied)
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 detailed patient phenotype or family history is 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 external pathogenic assertions are found. 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: it is absent from 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: its frequency is zero in controls. 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 observations in healthy individuals. 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, oncogenic 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 studies. 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 frameshift LoF 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 such phase data are available. 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 known function". The evidence for this variant shows: it is an out-of-frame insertion/deletion. Therefore, this criterion is not applied.
BP4 (Not Applied)
According to standard ACMG guidelines, the rule for BP4 is: "Multiple lines of computational evidence suggest no impact". The evidence for this variant shows: computational predictions are minimal and the variant is a frameshift. Therefore, this criterion is not applied.
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 such cases are 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 reports exist. 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 frameshift, not synonymous. Therefore, this criterion is not applied.