Genetic Information

Gene & Transcript Details

Gene
MLH1
Transcript
NM_000249.4 MANE Select
Total Exons
Reference Sequence
NC_000003.11
Alternative Transcripts
IDStatusDetails
NM_000249.3 RefSeq Select 2662 nt | 199–2469
NM_000249.2 Alternative 2524 nt | 61–2331
NM_000249.4 MANE Select 2494 nt | 31–2301

Variant Details

HGVS Notation
NM_000249.4:c.1230C>T
Protein Change
A410=
Location
Exon 12 (Exon 12 of )
12
5'Exon Structure3'
Functional Consequence
Loss of Function
Alternate Identifiers

Clinical & Population Data

Population Frequency

gnomAD
Global Frequency
0.000398 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
3 publications
Clinical Statement

"This variant has been reported in ClinVar as Likely benign (4 clinical laboratories) and as Likely Benign (1 clinical laboratories) and as Benign (1 clinical laboratories)."

COSMIC Somatic Evidence

Open
COSMIC ID
Recurrence
0 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 MLH1.

Functional Studies & Therapeutic Relevance

Functional Summary

The 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
Mixed/VUS
PP3 Applied
No
REVEL Score
0.0
Threshold: ≥0.75 = PP3 applied

SpliceAI Scores

Window: ±500bp
Effect Type Score Position
- Acceptor Loss (AL) 0.02 -191 bp
- Donor Loss (DL) 0.01 179 bp
+ Acceptor Gain (AG) 0.0 45 bp
+ Donor Gain (DG) 0.02 -81 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 VCEP guidelines, PVS1 applies to null variants (nonsense, frameshift, canonical ±1–2 splice sites, initiation codon, or multi-exon deletions) predicted to undergo NMD. The evidence for this variant shows a synonymous change (A410=) with no predicted splicing impact. Therefore, this criterion is not applied.

PS1

PS1 (Not Applied)

According to VCEP guidelines, PS1 applies when a variant results in the same amino acid change as a known pathogenic variant. The evidence for this variant shows no amino acid change (synonymous). Therefore, this criterion is not applied.

PS2

PS2 (Not Applied)

According to standard ACMG guidelines, PS2 applies for confirmed de novo occurrences. There is no reported de novo data for this variant. Therefore, this criterion is not applied.

PS3

PS3 (Not Applied)

According to VCEP guidelines, PS3 requires validated functional assays showing a deleterious effect. No functional studies are available for this variant. Therefore, this criterion is not applied.

PS4

PS4 (Not Applied)

According to standard ACMG guidelines, PS4 applies when the variant is significantly enriched in affected individuals. No case-control or segregation data are available. Therefore, this criterion is not applied.

PM1

PM1 (Not Applied)

According to standard ACMG guidelines, PM1 applies to variants in mutational hotspots or critical functional domains. This synonymous variant does not alter a known functional domain. Therefore, this criterion is not applied.

PM2

PM2 (Supporting)

According to VCEP guidelines, the rule for PM2 is: "Supporting Absent/extremely rare (<1 in 50,000 alleles) in gnomAD v4 dataset." The evidence for this variant shows MAF = 0.000398% (1/251326 alleles), which is <1/50,000. Therefore, PM2 is applied at Supporting strength.

PM3

PM3 (Not Applied)

According to VCEP guidelines, PM3 applies for recessive disorders with variants in trans. No evidence of trans observations is available. Therefore, this criterion is not applied.

PM4

PM4 (Not Applied)

According to standard ACMG guidelines, PM4 applies to protein length changes due to in-frame indels or stop-loss. This is a synonymous variant with no protein length change. Therefore, this criterion is not applied.

PM5

PM5 (Not Applied)

According to VCEP guidelines, PM5 applies for novel missense changes at residues with known pathogenic missense variants. This variant is synonymous. Therefore, this criterion is not applied.

PM6

PM6 (Not Applied)

According to standard ACMG guidelines, PM6 applies to assumed de novo cases without confirmation. No such data exist. Therefore, this criterion is not applied.

PP1

PP1 (Not Applied)

According to VCEP guidelines, PP1 applies for segregation evidence. No family segregation data are available. Therefore, this criterion is not applied.

PP2

PP2 (Not Applied)

According to standard ACMG guidelines, PP2 applies to missense variants in genes with low benign missense variation. This is synonymous. Therefore, this criterion is not applied.

PP3

PP3 (Not Applied)

According to VCEP guidelines, PP3 (Supporting) applies for predicted splice defect with SpliceAI ≥0.2 or high HCI-prior. SpliceAI delta = 0.02, below threshold. Therefore, this criterion is not applied.

PP4

PP4 (Not Applied)

According to VCEP guidelines for MLH1, PP4 applies for tumor phenotype data (MSI-H or loss of expression). No tumor data are provided. Therefore, this criterion is not applied.

PP5

PP5 (Not Applied)

According to standard ACMG guidelines, PP5 applies for reputable sources reporting pathogenic. No such report exists for pathogenicity. Therefore, this criterion is not applied.

BA1

BA1 (Not Applied)

According to VCEP guidelines, BA1 applies for MAF ≥0.001 (0.1%). The variant MAF = 0.000398% is below this threshold. Therefore, this criterion is not applied.

BS1

BS1 (Not Applied)

According to VCEP guidelines, BS1 applies for MAF ≥0.0001 (0.01%) and <0.001. The variant MAF = 0.000398% is 0.00000398 in fractional terms, below 0.0001. Therefore, this criterion is not applied.

BS2

BS2 (Not Applied)

According to VCEP guidelines, BS2 applies for co-occurrence in trans with a pathogenic variant in LS cancers. No such data are available. Therefore, this criterion is not applied.

BS3

BS3 (Not Applied)

According to VCEP guidelines, BS3 (Strong) applies for functional assays showing no mRNA or protein impact. No functional assays have been performed. Therefore, this criterion is not applied.

BS4

BS4 (Not Applied)

According to standard ACMG guidelines, BS4 applies for lack of segregation. No segregation data exist. Therefore, this criterion is not applied.

BP1

BP1 (Not Applied)

According to standard ACMG guidelines, BP1 applies to missense in genes where only truncating variants cause disease. This is synonymous. Therefore, this criterion is not applied.

BP2

BP2 (Not Applied)

According to standard ACMG guidelines, BP2 applies for observed in trans with a pathogenic variant for a dominant disorder. No such data are available. Therefore, this criterion is not applied.

BP3

BP3 (Not Applied)

According to standard ACMG guidelines, BP3 applies to in-frame indels in repetitive regions. This is a single-nucleotide synonymous variant. Therefore, this criterion is not applied.

BP4

BP4 (Supporting)

According to VCEP guidelines, BP4: "Supporting … For intronic and synonymous variants: SpliceAI predicts no splicing impact with delta score <= 0.1 as per Walker et al 2023." The evidence shows SpliceAI delta = 0.02, indicating no splicing impact. Therefore, BP4 is applied at Supporting strength.

BP5

BP5 (Not Applied)

According to VCEP guidelines, BP5 applies for variants found in a case with an alternate molecular basis. No such data are available. Therefore, this criterion is not applied.

BP6

BP6 (Supporting)

According to standard ACMG guidelines, BP6: "Supporting—Reputable source reports benign, evidence not available to the laboratory." ClinVar reports this variant as Likely benign/Benign by multiple labs. Therefore, BP6 is applied at Supporting strength.

BP7

BP7 (Supporting)

According to VCEP guidelines, BP7: "Supporting—A synonymous (silent) or intronic variant at or beyond -21/+7 (5′/3′ exonic). Variants may satisfy both BP7 and BP4." The variant is synonymous and SpliceAI predicts no splicing impact. Therefore, BP7 is applied at Supporting strength.