chr3-37049007-C-G

Variant names:

• chr3-37049007-C-G
• rs587778975
• NM_000249.4:c.2093C>G

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000249.4(MLH1):​c.2093C>G​(p.Ser698*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MLH1 NM_000249.4 stop_gained
• Clinical Significance: Pathogenic reviewed by expert panel P:6
• Conservation: PhyloP100: 4.57

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]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most 50 bp of the penultimate exon, not predicted to undergo nonsense mediated mRNA decay. There are 27 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-37049007-C-G is Pathogenic according to our data. Variant chr3-37049007-C-G is described in ClinVar as [Pathogenic]. Clinvar id is 90040.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37049007-C-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4	c.2093C>G	p.Ser698*	stop_gained	Exon 18 of 19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.2093C>G	p.Ser698*	stop_gained	Exon 18 of 19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:6

Revision: reviewed by expert panel

Submissions by phenotype

Lynch syndrome Pathogenic:2

Sep 05, 2013

International Society for Gastrointestinal Hereditary Tumours (InSiGHT)

Significance: Pathogenic

Review Status: reviewed by expert panel

Collection Method: research

Coding sequence variation resulting in a stop codon -

Aug 21, 2018

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

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MLH1 c.2093C>G (p.Ser698X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. Truncations downstream of this position have been classified as pathogenic by our laboratory (e.g. c.2141G>A (p.Trp714X), c.2142G>A (p.Trp714X), c.2179_2182delCACA (p.His727fsX55)). The variant was absent in 245618 control chromosomes (gnomAD). c.2093C>G has been reported in the literature in individuals affected with Lynch Syndrome (Rossi 2017, Sunga 2017). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Jun 13, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant changes 1 nucleotide in exon 18 of the MLH1 gene, creating a premature translation stop signal in the last coding exon. This variant is predicted to escape nonsense-mediated decay and be expressed as a truncated protein. Although functional studies have not been reported, this variant is expected to disrupt the PMS2/MLH3/PMS1 interacting domain (PMID: 12799449, 16338176, 20533529). This variant has been reported in a family affected with Lynch syndrome in El Salvador (PMID: 28874130). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MLH1 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Pathogenic. -

Apr 29, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.S698* pathogenic mutation (also known as c.2093C>G), located in coding exon 18 of the MLH1 gene, results from a C to G substitution at nucleotide position 2093. This changes the amino acid from a serine to a stop codon within coding exon 18. This alteration occurs at the 3' terminus of theMLH1 gene, is not expected to trigger nonsense-mediated mRNA decay, and only impacts the last 59 amino acids of the protein. However, premature stop codons are typically deleterious in nature and a significant portion of the protein is affected (Ambry internal data). This alteration has been reported in one Lynch syndrome family (Sunga AY et al. Cancer Genet, 2017 Apr;212-213:1-7). Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -

Colorectal cancer, hereditary nonpolyposis, type 2 Pathogenic:1

Jul 25, 2023

Myriad Genetics, Inc.

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered pathogenic. This variant creates a termination codon and is predicted to result in premature protein truncation. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Sep 04, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Ser698*) in the MLH1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 59 amino acid(s) of the MLH1 protein. This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 28449805, 28874130). ClinVar contains an entry for this variant (Variation ID: 90040). This variant disrupts a region of the MLH1 protein in which other variant(s) (p.Tyr750*) have been determined to be pathogenic (PMID: 10422993, 16338176, 20533529). This suggests that this is a clinically significant region of the protein, and that variants that disrupt it are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.46
CADD	Pathogenic	38
DANN	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.91
FATHMM_MKL	Uncertain	0.81	D
Vest4		0.91
GERP RS		5.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs587778975; hg19: chr3-37090498; COSMIC: COSV99212376; COSMIC: COSV99212376;