NM_000249.4:c.1897-7C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_000249.4(MLH1):c.1897-7C>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000236 in 1,609,460 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/2 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 31)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

MLH1
NM_000249.4 splice_region, intron

Scores

Splicing: ADA: 0.0001286

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:6O:1

Conservation

PhyloP100: 0.101

Publications

1 publications found

Variant links:

Genes affected

MLH1 (HGNC:7127): (mutL homolog 1) The protein encoded by this gene can heterodimerize with mismatch repair endonuclease PMS2 to form MutL alpha, part of the DNA mismatch repair system. When MutL alpha is bound by MutS beta and some accessory proteins, the PMS2 subunit of MutL alpha introduces a single-strand break near DNA mismatches, providing an entry point for exonuclease degradation. The encoded protein is also involved in DNA damage signaling and can heterodimerize with DNA mismatch repair protein MLH3 to form MutL gamma, which is involved in meiosis. This gene was identified as a locus frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). [provided by RefSeq, Aug 2017]

MLH1 Gene-Disease associations (from GenCC):

Lynch syndrome
Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
Lynch syndrome 2
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
Muir-Torre syndrome
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet
mismatch repair cancer syndrome 1
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
Lynch syndrome 1
Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
ovarian cancer
Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
malignant pancreatic neoplasm
Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
rhabdomyosarcoma
Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
prostate cancer
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
breast cancer
Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
hereditary breast carcinoma
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

MLH1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -5 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.73).

BP6

Variant 3-37048510-C-T is Benign according to our data. Variant chr3-37048510-C-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 405407.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.1897-7C>T		splice_region_variant, intron_variant	Intron 16 of 18	ENST00000231790.8	NP_000240.1	P40692-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 link	c.1897-7C>T		splice_region_variant, intron_variant	Intron 16 of 18	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.00000658

AC:

AN:

152018

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000242

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000398

AC:

AN:

251320

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000254

AC:

AN:

1457442

Hom.:

Cov.:

AF XY:

0.0000221

AC XY:

AN XY:

725390

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33366

American (AMR)

AF:

0.00

AC:

AN:

44718

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26102

East Asian (EAS)

AF:

0.00

AC:

AN:

39678

South Asian (SAS)

AF:

0.00

AC:

AN:

86136

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53386

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.0000307

AC:

AN:

1108050

Other (OTH)

AF:

0.0000498

AC:

AN:

60248

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.466

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000658

AC:

AN:

152018

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74252

show subpopulations

African (AFR)

AF:

0.0000242

AC:

AN:

41400

American (AMR)

AF:

0.00

AC:

AN:

15258

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5172

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10586

Middle Eastern (MID)

AF:

0.00

AC:

AN:

314

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67992

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000151

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2Benign:6Other:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:1Benign:1

Nov 08, 2022

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The frequency of this variant in the general population, 0.000004 (1/251320 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. In the published literature, the variant has been reported in the somatic state in a tumor sample (PMID: 29887214 (2018)). Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on MLH1 mRNA splicing yielded predictions that this variant may result in the gain of a cryptic splice site without affecting the natural splice sites . Based on the available information, we are unable to determine the clinical significance of this variant. -

May 02, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Benign:2

Dec 07, 2020

Color Diagnostics, LLC DBA Color Health

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 09, 2020

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Lynch syndrome

Uncertain:1

May 01, 2018

University of Washington Department of Laboratory Medicine, University of Washington

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

MLH1 NM_000249.3:c.1897-7C>T has a 7.8% probability of pathogenicity based on combining prior probability from public data with a likelihood ratio of 0.16 to 1, generated from evidence of seeing this as a somatic mutation in a tumor with loss of heterozygosity at the MLH1 locus. See Shirts et al 2018, PMID 29887214. -

not specified

Benign:1

Apr 25, 2025

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: MLH1 c.1897-7C>T alters a non-conserved nucleotide located at a position not widely known to affect splicing. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 2.4e-05 in 1602478 control chromosomes in the gnomAD database (v4.1 dataset). This frequency is not significantly higher than estimated for a pathogenic variant in MLH1 causing Hereditary Nonpolyposis Colorectal Cancer (2.4e-05 vs 0.00071), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.1897-7C>T in individuals affected with Hereditary Nonpolyposis Colorectal Cancer and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 405407). Based on the evidence outlined above, the variant was classified as likely benign. -

Colorectal cancer, hereditary nonpolyposis, type 2

Benign:1

Nov 26, 2024

Myriad Genetics, Inc.

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is considered likely benign. This variant is intronic and is not expected to impact mRNA splicing. -

Hereditary nonpolyposis colorectal neoplasms

Benign:1

Jan 01, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary nonpolyposis colon cancer

Other:1

GenomeConnect - Invitae Patient Insights Network

Significance:not provided

Review Status:no classification provided

Collection Method:phenotyping only

Variant interpreted as Uncertain significance and reported on 12-23-2016 by Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.73

CADD

Benign

9.0

(source)

DANN

Benign

0.64

PhyloP100

0.10

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00013

SpliceAI score (max)

0.10

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over