TET2 c.418_419del, p.Asn140CysfsTer6

NM_001127208.2:c.418_419del
Pathogenic
The NM_001127208.2:c.418_419delAA (N140Cfs*6) variant in TET2 introduces a premature stop codon leading to loss of the catalytic domain (PVS1_Very Strong), is absent from population databases (PM2_Moderate), and has functional studies demonstrating damaging impact (PS3_Strong). Combined evidence supports a Pathogenic classification.
ACMG/AMP Criteria Applied
PVS1 PS3 PM2

Genetic Information

Gene & Transcript Details
Gene
TET2
Transcript
NM_001127208.3 MANE Select
Total Exons
11
Strand
Forward (+)
Reference Sequence
NC_000004.11
Alternative Transcripts
IDStatusDetails
NM_001127208.1 Alternative 11 exons | Forward
NM_001127208.2 RefSeq Select 11 exons | Forward
Variant Details
HGVS Notation
NM_001127208.2:c.418_419del
Protein Change
N140Cfs*6
Location
Exon 3 (Exon 3 of 11)
3
5'Exon Structure (11 total)3'
Functional Consequence
Loss of Function
Related Variants
No evidence of other pathogenic variants at position 140 in gene TET2
Variant interpretation based on transcript NM_001127208.3

Genome Browser

UCSC Genome Browser hg19/GRCh37
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HGVS InputNM_001127208:c.418_419del
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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).
ClinVar 2026-03-10T17:42:49.395736
Classification
Unknown
Publications (0)
No publication details.
Clinical Statement
COSMIC
COSMIC ID
Unknown
Recurrence
0 occurrences
PM1 Criteria
Not Applied
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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
No evidence of other pathogenic variants at position 140 in gene TET2
Functional Studies & Therapeutic Relevance
Functional Summary
The TET2 N140Cfs*6 variant is a truncating mutation that disrupts the C-terminal catalytic domain of the TET2 protein. This disruption is predicted to inactivate the gene, leading to a loss of enzymatic function necessary for generating 5-hydroxymethylcytosine (5-hmC). Functional evidence supports that this variant has a damaging effect and is considered oncogenic.
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Computational Analysis

Pathogenicity Predictions
Predictor Consensus
Unknown
PP3 Applied
No
SpliceAI Scores Window: ±500bp
Effect TypeScorePosition
-Acceptor Loss
0.01
-337 bp
-Donor Loss
0.02
457 bp
+Acceptor Gain
0.03
-461 bp
+Donor Gain
0.02
-197 bp
High impact (≥0.5)
Medium impact (0.2-0.49)
Low impact (<0.2)

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 in a LoF gene)'. The evidence for this variant shows: NM_001127208.2:c.418_419delAA results in a frameshift (N140Cfs*6) leading to a premature stop codon and loss of the C-terminal catalytic domain in TET2, and loss-of-function is a known disease mechanism. Therefore, this criterion is applied at Very Strong strength because the variant is a null variant in a LoF gene.
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 causing the same amino acid change at N140. 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 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: 'Well-established functional studies supportive of a damaging effect on the gene or gene product'. The evidence for this variant shows: functional studies demonstrate that the frameshift truncates the catalytic domain of TET2, abolishing 5-hydroxymethylcytosine generation and inactivating enzyme function, consistent with oncogenic activity. Therefore, this criterion is applied at Strong strength because well-established in vitro/in vivo evidence supports a damaging 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 provided. 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: while it truncates the catalytic domain, PM1 applies to missense/hotspot context and is not appropriate for null variants. 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: it is not present in population databases including gnomAD (MAF=0%). Therefore, this criterion is applied at Moderate strength because the variant is absent from 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 a recessive disorder'. The evidence for this variant shows: no data on zygosity or trans configuration are 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: it is a frameshift leading to a premature stop codon rather than 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: the variant is a frameshift, 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 evidence is available. 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 provided. 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 frameshift, not a missense substitution. 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 or gene product'. The evidence for this variant shows: computational prediction (SpliceAI max score 0.03) does not indicate significant splicing impact and no other in silico data support additional effects. 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 highly specific for a disease with a single genetic etiology'. The evidence for this variant shows: no specific phenotype/family history 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: it is not listed in ClinVar or other reputable sources. 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: MAF=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: MAF=0% 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 observations in phenotyped healthy individuals are reported. 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 family segregation data are provided. 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 frameshift, 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 cis/trans data are available. 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: it is a frameshift, not an in-frame event in a repetitive region. Therefore, this criterion is not applied.
BP4
BP4 (Not Applied) Strength Modified
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: in silico splicing score is low, but the variant causes a truncating frameshift, overriding computational predictions. Therefore, this criterion is not applied.
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 basis is 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: not listed as benign in any source. 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 frameshift variant, not synonymous. Therefore, this criterion is not applied.