rs550914672

Variant names:

Your query was ambiguous. Multiple possible variants found:

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP3

The NM_000249.4(MLH1):c.991G>A(p.Glu331Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000013 in 1,614,162 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000033 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:13B:1

Conservation

PhyloP100: 9.29

Variant links:

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 1 ACMG points.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.804

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4 link	c.991G>A	p.Glu331Lys	missense_variant	Exon 11 of 19	ENST00000231790.8	NP_000240.1	P40692-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 link	c.991G>A	p.Glu331Lys	missense_variant	Exon 11 of 19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000329

AC:

AN:

152168

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000199

AC:

AN:

251340

Hom.:

AF XY:

0.0000221

AC XY:

AN XY:

135854

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000578

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:

0.00000880

Gnomad OTH exome

AF:

0.000326

GnomAD4 exome

AF:

0.0000109

AC:

AN:

1461876

Hom.:

Cov.:

AF XY:

0.0000124

AC XY:

AN XY:

727242

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000201

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.0000328

AC:

AN:

152286

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74454

show subpopulations

Gnomad4 AFR

AF:

0.0000481

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000508

Hom.:

Bravo

AF:

0.0000113

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:13Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:3

Jul 11, 2022

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MLH1 c.991G>A (p.Glu331Lys) results in a conservative amino acid change located in the DNA mismatch repair protein, S5 domain 2-like domain (IPR013507) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2e-05 in 251340 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.991G>A has been reported in the literature in individuals diagnosed with breast cancer and medulloblastoma without evidence for causality (example: Zhang_2015 and Kwong_2020). These reports do not provide unequivocal conclusions about association of the variant with Lynch Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Eight clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 and all classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Dec 31, 2020

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

DNA sequence analysis of the MLH1 gene demonstrated a sequence change, c.991G>A, in exon 11 that results in an amino acid change, p.Glu331Lys. This sequence change does not appear to have been previously described in individuals with MLH1-related disorders and has been described in the gnomAD database in six individuals with an overall population frequency of 0.0021% (dbSNP rs550914672). The p.Glu331Lys change affects a highly conserved amino acid residue located in a domain of the MLH1 protein that is known to be functional. The p.Glu331Lys substitution appears to be deleterious using several in-silico pathogenicity prediction tools (SIFT, PolyPhen2, Align GVGD, REVEL). Due to these contrasting evidences and the lack of functional studies, the clinical significance of the p.Glu331Lys change remains unknown at this time. -

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:3

May 18, 2021

Sema4, Sema4

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: curation

- -

Sep 24, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.E331K variant (also known as c.991G>A), located in coding exon 11 of the MLH1 gene, results from a G to A substitution at nucleotide position 991. The glutamic acid at codon 331 is replaced by lysine, an amino acid with similar properties. 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 available evidence, the clinical significance of this variant remains unclear. -

Feb 21, 2023

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces glutamic acid with lysine at codon 331 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). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in an individual with breast and/or ovarian cancer (PMID: 32068069) and an individual with medulloblastoma (PMID: 26580448). This variant has been identified in 6/282742 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. -

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:2Benign:1

Nov 25, 2019

Division of Medical Genetics, University of Washington

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

To our knowledge, this sequence variant has not been previously reported in the literature. This variant has an overall allele frequency of 0.00002 in the Broad Institute gnomAD Browser (https://gnomad.broadinstitute.org/). In silico analyses indicate this is an evolutionarily conserved residue. Thus, it is unknown at this time whether this variant increases cancer risk. PP3 -

Nov 21, 2024

Myriad Genetics, Inc.

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 27363726]. -

Mar 27, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided

Uncertain:2

Dec 15, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in a patient with breast and/or gynecologic cancer (PMID: 32068069); This variant is associated with the following publications: (PMID: 28481359, 22753075, 25892863, 32068069) -

Aug 27, 2021

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Lynch syndrome

Uncertain:1

Dec 18, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

MLH1-related disorder

Uncertain:1

Oct 12, 2023

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MLH1 c.991G>A variant is predicted to result in the amino acid substitution p.Glu331Lys. This variant has previously been reported as a variant of uncertain significance in a cohort of individuals with breast and/or ovarian cancer (Kwong et al. 2020. PubMed ID: 32068069, supplementary data) and in an individual with medulloblastoma (Zhang et al. 2015. PubMed ID: 26580448, supplementary data). This variant is reported in 0.0085% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/3-37061907-G-A) and is interpreted as uncertain significance in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/230317/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamic acid, which is acidic and polar, with lysine, which is basic and polar, at codon 331 of the MLH1 protein (p.Glu331Lys). This variant is present in population databases (rs550914672, gnomAD 0.01%). This missense change has been observed in individual(s) with clinical features of MLH1-related conditions and/or personal history of breast and/or ovarian cancer (PMID: 21520333, 26580448, 32068069). ClinVar contains an entry for this variant (Variation ID: 230317). Invitae Evidence Modeling incorporating data from in vitro experimental studies (internal data) indicates that this missense variant is not expected to disrupt MLH1 function with a negative predictive value of 95%. 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. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.78

BayesDel_addAF

Pathogenic

0.26

BayesDel_noAF

Pathogenic

0.34

CADD

Pathogenic

DANN

Pathogenic

1.0

DEOGEN2

Uncertain

0.69

D;.;.;.;.;.;.

Eigen

Pathogenic

0.78

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Pathogenic

0.98

D;D;.;.;.;D;D

M_CAP

Benign

0.083

MetaRNN

Pathogenic

0.80

D;D;D;D;D;D;D

MetaSVM

Uncertain

0.25

MutationAssessor

Benign

1.5

L;.;.;.;.;.;.

PrimateAI

Uncertain

0.64

PROVEAN

Uncertain

-2.8

D;D;D;D;D;D;D

REVEL

Pathogenic

0.74

Sift

Uncertain

0.0050

D;D;D;D;D;D;D

Sift4G

Uncertain

0.022

D;D;D;D;D;T;D

Polyphen

1.0

D;.;.;.;.;.;.

Vest4

0.81

MVP

0.98

MPC

0.36

ClinPred

0.97

GERP RS

5.2

Varity_R

0.76

gMVP

0.48

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over