3-37020353-A-G

Position:

chr3-37020353-A-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1PP3_Moderate

The NM_000249.4(MLH1):c.928A>G(p.Thr310Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000684 in 1,461,890 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T310K) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 0.0000068 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9B:1

Conservation

PhyloP100: 8.88

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 4 ACMG points.

PM1

In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 15 uncertain in NM_000249.4

PP3

MetaRNN computational evidence supports a deleterious effect, 0.87

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.928A>G	p.Thr310Ala	missense_variant	11/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.928A>G	p.Thr310Ala	missense_variant	11/19	1	NM_000249.4	P1	P40692-1

Frequencies

GnomAD3 genomes

Cov.:

GnomAD3 exomes

AF:

0.0000239

AC:

AN:

251418

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135878

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000173

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000684

AC:

AN:

1461890

Hom.:

Cov.:

AF XY:

0.00000413

AC XY:

AN XY:

727248

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.000201

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

8.99e-7

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

Cov.:

Alfa

AF:

0.0000370

Hom.:

Bravo

AF:

0.00000378

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:9Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:2Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Nov 14, 2023	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]. -
Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 28, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Sep 10, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	May 15, 2017	This variant is denoted MLH1 c.928A>G at the cDNA level, p.Thr310Ala (T310A) at the protein level, and results in the change of a Threonine to an Alanine (ACA>GCA). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. MLH1 Thr310Ala was observed at an allele frequency of 0.02% (3/11578) in individuals of Latino ancestry in large population cohorts (NHLBI Exome Sequencing Project, The 1000 Genomes Consortium 2015, Lek 2016). Since Threonine and Alanine differ in polarity, charge, size or other properties, this is considered a non-conservative amino acid substitution. MLH1 Thr310Ala occurs at a position that is conserved across species and is located within the N-terminal ATPase domain (Andersen 2012). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available evidence, it is unclear whether MLH1 Thr310Ala is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Jan 23, 2023	This missense variant replaces threonine with alanine at codon 310 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 affected with colorectal cancer (PMID: 32973888). This variant has been identified in 6/251418 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Mar 21, 2024	The p.T310A variant (also known as c.928A>G), located in coding exon 11 of the MLH1 gene, results from an A to G substitution at nucleotide position 928. The threonine at codon 310 is replaced by alanine, an amino acid with similar properties. This variant was identified in a 32 year old male with MMR-deficient colorectal cancer, but specific results from IHC analysis were not provided by the authors (Xu Y et al. Front Genet, 2020 Aug;11:991). This amino acid position is highly 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

Jan 15, 2024

Variant summary: MLH1 c.928A>G (p.Thr310Ala) results in a non-conservative amino acid change located in the DNA mismatch repair protein, S5 domain 2-like domain (IPR013507) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 2.4e-05 in 251418 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.928A>G has been reported in the literature in at least one individual affected with colorectal cancer and MMR deficiency (e.g., Xu_2020). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 32973888). ClinVar contains an entry for this variant (Variation ID: 237351). 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

Dec 18, 2023

This missense variant replaces threonine with alanine at codon 310 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 affected with colorectal cancer (PMID: 32973888). This variant has been identified in 6/251418 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

Jan 03, 2024

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 310 of the MLH1 protein (p.Thr310Ala). This variant is present in population databases (rs779581111, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with MLH1-related conditions. ClinVar contains an entry for this variant (Variation ID: 237351). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on MLH1 protein function. 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

0.83

BayesDel_addAF

Pathogenic

0.24

BayesDel_noAF

Pathogenic

0.37

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.76

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

Eigen

Pathogenic

0.81

Eigen_PC

Pathogenic

0.77

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

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

M_CAP

Uncertain

0.26

MetaRNN

Pathogenic

0.87

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

MetaSVM

Uncertain

0.43

MutationAssessor

Uncertain

2.5

M;.;.;.;.;.;.

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.73

PROVEAN

Pathogenic

-4.9

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

REVEL

Pathogenic

0.86

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0

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

Polyphen

1.0

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

Vest4

0.79

MutPred

0.66

Loss of glycosylation at T310 (P = 0.0147);.;.;.;.;.;.;

MVP

0.96

MPC

0.40

ClinPred

0.93

GERP RS

5.8

Varity_R

0.90

gMVP

0.60

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.020

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