rs63750211

chr3-37008904-A-G

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PM5 PP3_Moderate PP5_Very_Strong

The NM_000249.4(MLH1):c.544A>G(p.Arg182Gly) variant causes a missense, splice region 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. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R182K) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MLH1 NM_000249.4 missense, splice_region
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Pathogenic reviewed by expert panel P:3 U:1
• Conservation: PhyloP100: 8.15

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 16 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr3-37008905-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 90264.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 3-37008904-A-G is Pathogenic according to our data. Variant chr3-37008904-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 90258.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37008904-A-G is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4	c.544A>G	p.Arg182Gly	missense_variant, splice_region_variant	6/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8	c.544A>G	p.Arg182Gly	missense_variant, splice_region_variant	6/19	1	NM_000249.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3 Uncertain:1

Revision: reviewed by expert panel

Submissions by phenotype

Lynch syndrome Pathogenic:1

Pathogenic, reviewed by expert panel

research

International Society for Gastrointestinal Hereditary Tumours (InSiGHT)

Sep 05, 2013

Variant causes splicing aberration which introduces frameshift (no full-length expressed from allele) -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Dec 12, 2023

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 182 of the MLH1 protein (p.Arg182Gly). RNA analysis indicates that this missense change induces altered splicing and may result in an absent or disrupted protein product. This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Lynch syndrome (PMID: 10480359, 16395668, 19459153, 21404117, 22773173). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 90258). Based on a multifactorial likelihood algorithm using genetic, in silico, and/or statistical data, this variant has been determined to have a high probability of being pathogenic (PMID: 24362816). Studies have shown that this missense change results in skipping of exon 6 and introduces a premature termination codon (PMID: 16395668). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 04, 2016

The p.R182G pathogenic mutation (also known as c.544A>G), located in coding exon 6 of the MLH1 gene, results from an A to G substitution at nucleotide position 544. The arginine at codon 182 is replaced by glycine, an amino acid with dissimilar properties. This alteration has been identified in multiple families either meeting Amsterdam II criteria or whose family history was suggestive of HNPCC/Lynch syndrome, and has also been shown to co-segregate with disease in a large Irish family (Chong G et al. Hum. Mutat., 2009 Aug;30:E797-812; Hardt K et al. Fam. Cancer, 2011 Jun;10:273-84; Wang Q et al. Int. J. Cancer, 1997 Dec;73:831-6; Farrell MP et al. Fam. Cancer, 2012 Sep;11:509-18). This alteration shows a dominant negative effect in reporter assays in yeast, MMR activity of 74.3% and MLH1 expression of 25-75% compared to wild type (Takahashi M et al. Cancer Res., 2007 May;67:4595-604). This alteration has also been shown to result in skipping and complete loss of coding exon 6 at the mRNA level (Auclair J et al. Hum. Mutat., 2006 Feb;27:145-54). This amino acid position is highly conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to weaken the efficiency of the native splice donor site; however, direct evidence is unavailable. In addition, this alteration is predicted to be deleterious by in silico analysis. In addition, this alteration is predicted to be deleterious by MAPP-MMR in silico analyses (Chao E et al. Hum Mutat. 2008 Jun;29(6):852-60). This alteration has also been classified as pathogenic by multifactorial analysis, which integrates the following lines of evidence to produce a quantitative likelihood of pathogenicity: in silico prediction models, segregation with disease, clinical phenotype including tumor characteristics, mutation co-occurrence, and functional assay results (Thompson B et al. Nat Genet. 2014 Feb;46(2):107-15; available at [www.insight-group.org/variants/classifications/]). Based on the available evidence, this alteration is classified as a pathogenic mutation. -

not provided Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.62
BayesDel_addAF	Pathogenic	0.48	D
BayesDel_noAF	Pathogenic	0.46
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.79	D;.
Eigen	Pathogenic	0.77
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Pathogenic	3.9	H;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.53	T
PROVEAN	Pathogenic	-5.7	D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.0030	D;D
Polyphen		0.98	D;.
Vest4		0.97
MutPred		0.86		Loss of MoRF binding (P = 0.0312);.;
MVP		0.99
MPC		0.36
ClinPred		1.0	D
GERP RS		4.5
Varity_R		0.86
gMVP		0.88

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.87		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.87		Position offset: 1

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

Publications

LitVar

Other links and lift over

dbSNP: rs63750211; hg19: chr3-37050395;