rs63750303

Positions:

• chr3-37014485-G-A
• chr3-37014485-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_000249.4(MLH1):​c.731G>A​(p.Gly244Asp) variant causes a missense 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 (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G244V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 33)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Pathogenic reviewed by expert panel P:7 O:1
• Conservation: PhyloP100: 9.52

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.

• PM1: In a strand (size 7) in uniprot entity MLH1_HUMAN there are 4 pathogenic changes around while only 1 benign (80%) 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 chr3-37014485-G-T is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.98
• PP5: Variant 3-37014485-G-A is Pathogenic according to our data. Variant chr3-37014485-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 90339.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37014485-G-A is described in Lovd as [Pathogenic]. Variant chr3-37014485-G-A is described in Lovd as [Benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.731G>A	p.Gly244Asp	missense_variant	9/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.731G>A	p.Gly244Asp	missense_variant	9/19	1	NM_000249.4	ENSP00000231790	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 28

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

Lynch syndrome Pathogenic:2

Pathogenic, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	Abrogated function, >2 MSI-H tumours, co-segregation with disease & MAF 0.00. Multifactorial likelihood analysis posterior probability >0.99 -
Pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Sep 21, 2017	Variant summary: The MLH1 c.731G>A (p.Gly244Asp) variant involves the alteration of a conserved nucleotide that results in a non-conservative amino acid substitution in the N-terminal part of the MLH1 protein which might be involved in protein interactions (InterPro). 4/4 in silico tools predict a damaging outcome for this variant (SNPsandGO not captured due to low reliability index). Published functional studies demonstrated that the variant protein virtually lost the ability to bind to its partner proteins (PMS2 or EXO1) and also resulted in a substantially decreased (19.4% of normal) in vitro MMR activity (Kondo 2003, Takahashi 2007). This variant is absent in 246120 control chromosomes. The variant was reported in multiple patients with colorectal cancer and other LS-associated tumors from Lynch syndrome families, including evidence of cosegregation with disease (e.g. Choi 2009, Bozzao 2011, Barrera 2017). In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as pathogenic. Taken together, this variant is classified as pathogenic. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 28, 2023	This missense variant replaces glycine with aspartic acid at codon 244 of the MLH1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). Functional studies have shown that this variant disrupts MLH1 binding to PMS2 and EXO1 (PMID: 12810663) and resulted in ~80% reduction in mismatch repair activity (PMID: 17510385). This variant has been reported in over ten individuals affected with Lynch syndrome and colorectal cancer (PMID: 17510385, 21387278). This variant has been shown to segregate with disease in four affected individuals from a Lynch syndrome family (PMID: 29184699). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Different variants affecting the same codon, c.730G>C (p.Gly244Arg) and c.731G>T (p.Gly244Val), are also considered to be disease-causing (ClinVar variation ID: 1758254, 90340), suggesting this position is important for the protein function. Based on the available evidence, this variant is classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	May 03, 2019	The p.G244D pathogenic mutation (also known as c.731G>A), located in coding exon 9 of the MLH1 gene, results from a G to A substitution at nucleotide position 731. The glycine at codon 244 is replaced by aspartic acid, an amino acid with similar properties. This alteration has been reported in numerous individuals with personal and/or family histories consistent with hereditary nonpolyposis colorectal cancer (HNPCC) (Bozzao C et al. Cancer, 2011 Sep;117:4325-35; Casey G et al. JAMA, 2005 Feb;293:799-809; Choi YH et al. Hered Cancer Clin Pract, 2009 Aug;7:14; Pensotti V et al. Genes Chromosomes Cancer, 1997 Jul;19:135-42; Wagner A et al. Am. J. Hum. Genet., 2003 May;72:1088-100). This alteration has also been shown to segregate with disease in three affected individuals (Blasi MF et al. Cancer Res., 2006 Sep;66:9036-44). Furthermore, this alteration has been reported as functionally defective in mismatch repair (Shcherbakova PV et al. Mol. Cell. Biol., 1999 Apr;19:3177-83; Trojan J et al. Gastroenterology, 2002 Jan;122:211-9; Kondo E et al. Cancer Res., 2003 Jun;63:3302-8; Takahashi M et al. Cancer Res., 2007 May;67:4595-604). This alteration has been classified as pathogenic using the following lines of evidence: in silico prediction models, segregation with disease, clinical phenotype including tumor characteristics, mutation co-occurrence, and functional studies (Thompson BA et al. Hum. Mutat. 2013 Jan;34:200-9; Thompson BA et al. Nat. Genet. 2014 Feb;46:107-15; available at [www.insight-group.org/variants/classifications/]). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Colorectal cancer, hereditary nonpolyposis, type 2 Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Baylor Genetics

Apr 06, 2021

- -

not provided Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

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- -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 20, 2023

This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 244 of the MLH1 protein (p.Gly244Asp). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with Lynch Syndrome (PMID: 9218993, 12658575, 15713769, 16982745, 21286823). ClinVar contains an entry for this variant (Variation ID: 90339). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MLH1 protein function with a positive predictive value of 95%. Experimental studies have shown that this missense change affects MLH1 function (PMID: 10082584, 11781295, 12810663, 16982745, 17510385). For these reasons, this variant has been classified as Pathogenic. -

Lynch syndrome 1 Other:1

not provided, no classification provided

literature only

GeneReviews

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.50	D
BayesDel_noAF	Pathogenic	0.48
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D;.;.;.;.;.;.
Eigen	Pathogenic	0.80
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.95	D;D;.;.;.;D;D
M_CAP	Pathogenic	0.57	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.85	D
MutationAssessor	Pathogenic	4.4	H;.;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.69	T
PROVEAN	Pathogenic	-5.5	D;D;D;D;D;D;D
REVEL	Pathogenic	0.89
Sift	Uncertain	0.0060	D;D;D;D;D;D;D
Sift4G	Uncertain	0.0080	D;D;D;D;D;D;D
Polyphen		0.97	D;.;.;.;.;.;.
Vest4		0.98
MutPred		0.91		Loss of catalytic residue at N243 (P = 0.1079);.;.;.;.;.;.;
MVP		0.99
MPC		0.44
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.98
gMVP		0.96

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: rs63750303; hg19: chr3-37055976;