rs786201875

Positions:

• chr3-37025679-A-G
• chr3-37025679-A-T

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_000249.4(MLH1):​c.1081A>G​(p.Lys361Glu) variant causes a missense change. The variant allele was found at a frequency of 0.00000137 in 1,459,878 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 30)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 6.77

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 Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.36857015).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1081A>G	p.Lys361Glu	missense_variant	12/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.1081A>G	p.Lys361Glu	missense_variant	12/19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250808 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135740

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000881

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1459878 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 726258

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 30

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Nov 12, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Apr 06, 2022	The p.K361E variant (also known as c.1081A>G), located in coding exon 12 of the MLH1 gene, results from an A to G substitution at nucleotide position 1081. The lysine at codon 361 is replaced by glutamic acid, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jun 30, 2022

Variant summary: MLH1 c.1081A>G (p.Lys361Glu) results in a conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4e-06 in 250808 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.1081A>G in individuals affected with Lynch Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. At-least one co-occurrence with another pathogenic variant(s) has been observed at our laboratory (MLH1 c.546-1G>A), providing supporting evidence for a benign role. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Lynch syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Oct 06, 2023

This missense variant replaces lysine with glutamic acid at codon 361 of the MLH1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MLH1-related disorders in the literature. This variant has been identified in 1/250808 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 17, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 not expected to disrupt MLH1 protein function. ClinVar contains an entry for this variant (Variation ID: 185023). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. This variant is present in population databases (rs786201875, gnomAD 0.0009%). This sequence change replaces lysine, which is basic and polar, with glutamic acid, which is acidic and polar, at codon 361 of the MLH1 protein (p.Lys361Glu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.20
CADD	Benign	22
DANN	Uncertain	0.99
DEOGEN2	Benign	0.33	T;.;.;.;.;.
Eigen	Benign	-0.24
Eigen_PC	Benign	-0.085
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Benign	0.79	T;T;.;.;.;T
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.37	T;T;T;T;T;T
MetaSVM	Benign	-0.42	T
MutationAssessor	Uncertain	2.4	M;.;.;.;.;.
PrimateAI	Uncertain	0.53	T
PROVEAN	Benign	-0.83	N;N;N;N;N;N
REVEL	Uncertain	0.44
Sift	Benign	0.32	T;T;T;T;T;T
Sift4G	Benign	0.45	T;T;T;T;T;T
Polyphen		0.0020	B;.;.;.;.;.
Vest4		0.56
MutPred		0.26		Loss of ubiquitination at K361 (P = 3e-04);.;.;.;.;.;
MVP		0.97
MPC		0.093
ClinPred		0.54	D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.18
gMVP		0.32

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: rs786201875; hg19: chr3-37067170;