Genetic Information

Gene & Transcript Details

Gene
KMT2A
Transcript
NM_005933.3 MANE Select
Total Exons
Reference Sequence
NC_000011.9
Alternative Transcripts
IDStatusDetails
NM_005933.4 Alternative 16591 nt | 22–11931
NM_005933.2 Alternative 14982 nt | 24–11933
NM_005933.3 Alternative 16599 nt | 24–11933

Variant Details

HGVS Notation
NM_005933.3:c.6779C>T
Protein Change
T2260I
Location
Exon 27 (Exon 27 of )
27
5'Exon Structure3'
Functional Consequence
Loss of Function
Alternate Identifiers

Clinical & Population Data

Population Frequency

gnomAD
Global Frequency
0.00398 in 100,000
Extremely Rare
ACMG Criteria Applied PM2
This variant is absent or extremely rare in population databases (PM2 criteria applies).

ClinVar

Open
Classification
Likely Benign
1 publications
Clinical Statement

"This variant has been reported in ClinVar as Likely benign (2 clinical laboratories)."

COSMIC Somatic Evidence

Open
COSMIC ID
COSM9114782
Recurrence
1 occurrences
PM1 Criteria
Not Applied
COSMIC Database Preview
COSMIC Preview
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Functional Impact & Domains

Functional Domain

Hotspot Status
Not a hotspot
Domain Summary
This variant is not located in a mutational hotspot or critical domain.
Related Variants in This Domain
No evidence of other pathogenic variants at this position in gene KMT2A.

Functional Studies & Therapeutic Relevance

Functional Summary

The KMT2A T2260I variant has not been functionally characterized.

Database Previews
OncoKB
OncoKB Preview
JAX-CKB
JAX-CKB Preview

Click on previews to view full database entries. External databases may require institutional access.

Computational Analysis

Pathogenicity Predictions

SpliceAI
Predictor Consensus
Unknown
PP3 Applied
No
REVEL Score
0.244
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.0 -282 bp
- Donor Loss (DL) 0.0 223 bp
+ Acceptor Gain (AG) 0.0 81 bp
+ Donor Gain (DG) 0.0 -244 bp
High impact (≥0.5) Medium impact (0.2-0.49) Low impact (<0.2)

VCEP Guidelines

Applied ACMG/AMP Criteria (VCEP Specific)

Filter Criteria:
PVS1

PVS1 (Not Applied)

According to standard ACMG guidelines, the rule for PVS1 is: 'Null variant in a gene where loss of function is a known mechanism of disease'. The evidence for this variant shows it is a missense change (c.6779C>T, p.T2260I). Therefore, this criterion is not applied because the variant is not a null variant.

PS1

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'. There is no report of any pathogenic variant causing the same p.T2260 amino acid change. Therefore, this criterion is not applied because no known pathogenic variant at this residue exists.

PS2

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'. There are no data on de novo occurrence or parental testing for this variant. Therefore, this criterion is not applied due to absence of de novo evidence.

PS3

PS3 (Not Applied)

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'. No functional studies have been performed for this variant. Therefore, this criterion is not applied because functional evidence is lacking.

PS4

PS4 (Not Applied)

According to standard ACMG guidelines, the rule for PS4 is: 'Prevalence in affected individuals significantly increased compared with controls'. There are no case–control or disease cohort data for this variant. Therefore, this criterion is not applied due to lack of case prevalence data.

PM1

PM1 (Not Applied)

According to standard ACMG guidelines, the rule for PM1 is: 'Located in a mutational hot spot or well-established functional domain without benign variation'. There is no evidence that residue T2260 lies in a known hot spot or critical functional domain. 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 a gnomAD MAF of 0.00398% (10/251,044 alleles) with no homozygotes, indicating it is extremely rare. Therefore, this criterion is applied at Moderate strength because the variant is absent or extremely rare in population databases.

PM3

PM3 (Not Applied)

According to standard ACMG guidelines, the rule for PM3 is: 'Detected in trans with a pathogenic variant for recessive disorders'. There are no data on cis/trans configuration with other variants. Therefore, this criterion is not applied due to lack of segregation in trans data.

PM4

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'. This variant is a missense change without effect on protein length. Therefore, this criterion is not applied.

PM5

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'. There are no reports of any other pathogenic missense changes at residue T2260. Therefore, this criterion is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, the rule for PM6 is: 'Assumed de novo, but without confirmation of paternity and maternity'. There are no data regarding de novo occurrence. Therefore, this criterion is not applied.

PP1

PP1 (Not Applied)

According to standard ACMG guidelines, the rule for PP1 is: 'Co-segregation with disease in multiple affected family members'. No family segregation data are available. Therefore, this criterion is not applied.

PP2

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'. KMT2A has both loss-of-function and some reported pathogenic missense variants. There is insufficient evidence that missense is the predominant mechanism. Therefore, this criterion is not applied.

PP3

PP3 (Not Applied)

According to standard ACMG guidelines, the rule for PP3 is: 'Multiple lines of computational evidence support a deleterious effect'. In silico tools (REVEL = 0.24, SpliceAI = 0.00) do not predict a deleterious effect. Therefore, this criterion is not applied.

PP4

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'. No clinical phenotype or family history data were provided. Therefore, this criterion is not applied.

PP5

PP5 (Not Applied)

According to standard ACMG guidelines, the rule for PP5 is: 'Reputable source reports variant as pathogenic, but without accessible evidence'. No reputable source reports this variant as pathogenic. Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to standard ACMG guidelines, the rule for BA1 is: 'Allele frequency is too high for the disorder'. The variant MAF of 0.00398% is well below thresholds for BA1. Therefore, this criterion is not applied.

BS1

BS1 (Not Applied)

According to standard ACMG guidelines, the rule for BS1 is: 'Allele frequency is greater than expected for the disorder'. The observed frequency is below any disease‐specific BS1 threshold. Therefore, this criterion is not applied.

BS2

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'. Although gnomAD individuals are presumably healthy, penetrance and age of onset data are lacking. Therefore, this criterion is not applied.

BS3

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'. No such functional studies exist. Therefore, this criterion is not applied.

BS4

BS4 (Not Applied)

According to standard ACMG guidelines, the rule for BS4 is: 'Lack of segregation in affected family members'. No family data are available to assess segregation. Therefore, this criterion is not applied.

BP1

BP1 (Not Applied)

According to standard ACMG guidelines, the rule for BP1 is: 'Missense variant in a gene where only loss of function causes disease'. KMT2A has reported pathogenic missense variants, indicating missense can be disease-causing. Therefore, this criterion is not applied.

BP2

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'. No data on cis/trans status with other variants are available. Therefore, this criterion is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, the rule for BP3 is: 'In-frame deletions/insertions in a repetitive region without known function'. This is a missense variant, not an indel. 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 or gene product'. The variant has REVEL = 0.24 (benign range) and SpliceAI = 0.00 (no splicing impact). Therefore, this criterion is applied at Supporting strength.

BP5

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'. No case‐level data or alternate molecular diagnoses are available. Therefore, this criterion is not applied.

BP6

BP6 (Supporting)

According to standard ACMG guidelines, the rule for BP6 is: 'Reputable source reports variant as benign, but without accessible evidence'. ClinVar entries from two clinical laboratories classify this variant as Likely benign without underlying evidence. Therefore, this criterion is applied at Supporting strength.

BP7

BP7 (Not Applied)

According to standard ACMG guidelines, the rule for BP7 is: 'Synonymous variant with no predicted impact on splicing'. This variant is missense, not synonymous. Therefore, this criterion is not applied.