chr3-37050588-G-T

Position:

• chr3-37050588-G-T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_000249.4(MLH1):​c.2206G>T​(p.Glu736*) variant causes a stop gained change involving the alteration of a conserved nucleotide. 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 criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 9.73

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 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. There are 8 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-37050588-G-T is Pathogenic according to our data. Variant chr3-37050588-G-T is described in ClinVar as [Pathogenic]. Clinvar id is 232190.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.2206G>T	p.Glu736*	stop_gained	19/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.2206G>T	p.Glu736*	stop_gained	19/19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Jul 25, 2023

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

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Feb 07, 2024

Nonsense variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss of function is a known mechanism of disease; Not observed at significant frequency in large population cohorts (gnomAD); Observed in an individual with colorectal cancer (PMID: 21286823); Truncating variants in this gene are considered pathogenic by a well-established clinical consortium and/or database; This variant is associated with the following publications: (PMID: 21387278, 30787465, 29345684, 28466842, 21286823, 34897210) -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jul 15, 2022

For these reasons, this variant has been classified as Pathogenic. 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. ClinVar contains an entry for this variant (Variation ID: 232190). This premature translational stop signal has been observed in individual(s) with Lynch syndrome (PMID: 21286823). This variant is not present in population databases (gnomAD no frequency). This sequence change creates a premature translational stop signal (p.Glu736*) in the MLH1 gene. While this is not anticipated to result in nonsense mediated decay, it is expected to disrupt the last 21 amino acid(s) of the MLH1 protein. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 10, 2019

The p.E736* pathogenic mutation (also known as c.2206G>T), located in coding exon 19 of the MLH1 gene, results from a G to T substitution at nucleotide position 2206. This changes the amino acid from a glutamic acid to a stop codon within coding exon 19. This mutation has been identified in individuals with colon cancer including one individual whose tumor demonstrated microsatellite instability (MSI-H) (Roberts ME et al. Genet. Med. 2018 10;20:1167-1174; Lastella P et al. Fam. Cancer 2011 Jun;10:285-95). This mutation has also been seen as a somatic alteration in conjunction with LOH in an MSI-H colorectal tumor demonstrating loss of MLH1 and PMS2 by IHC staining (Haraldsdottir S et al. Nat Commun, 2017 05;8:14755). In addition, structural analysis suggests that this alteration perturbs a known functional domain responsible for binding to and stabilizing PMS2 (Mohd AB et al. DNA Repair (Amst.), 2006 Mar;5:347-61). As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.59
CADD	Pathogenic	39
DANN	Uncertain	1.0
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	0.98	D
Vest4		0.79
ClinPred		1.0	D
GERP RS		5.4

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		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: rs876659608; hg19: chr3-37092079;