3-36993638-G-T

Position:

chr3-36993638-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 6P and 1B. PM1PM5PP3_ModerateBS1_Supporting

The NM_000249.4(MLH1):c.91G>T(p.Ala31Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000551 in 1,614,222 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. A31C) has been classified as Likely pathogenic.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000056 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:1

Conservation

PhyloP100: 9.49

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:

MLH1 (HGNC:):

MLH1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 5 ACMG points.

PM1

In a helix (size 13) in uniprot entity MLH1_HUMAN there are 19 pathogenic changes around while only 8 benign (70%) in NM_000249.4

PM5

Other missense variant is known to change same aminoacid residue: Variant chrnull-null-null-null is described in UniProt as null.

PP3

MetaRNN computational evidence supports a deleterious effect, 0.935

BS1

Variant frequency is greater than expected in population mid. gnomad4_exome allele frequency = 0.0000561 (82/1461864) while in subpopulation MID AF= 0.00173 (10/5768). AF 95% confidence interval is 0.00094. There are 0 homozygotes in gnomad4_exome. There are 50 alleles in male gnomad4_exome subpopulation. Median coverage is 31. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.91G>T	p.Ala31Ser	missense_variant	1/19	ENST00000231790.8	NP_000240.1	P40692-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.91G>T	p.Ala31Ser	missense_variant	1/19	1	NM_000249.4	ENSP00000231790.3		P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152240

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.000955

GnomAD3 exomes

AF:

0.0000836

AC:

AN:

251118

Hom.:

AF XY:

0.0000957

AC XY:

AN XY:

135792

show subpopulations

Gnomad AFR exome

AF:

0.0000615

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000294

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000882

Gnomad OTH exome

AF:

0.000163

GnomAD4 exome

AF:

0.0000561

AC:

AN:

1461864

Hom.:

Cov.:

AF XY:

0.0000688

AC XY:

AN XY:

727236

show subpopulations

Gnomad4 AFR exome

AF:

0.000179

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000315

Gnomad4 OTH exome

AF:

0.000166

GnomAD4 genome

AF:

0.0000459

AC:

AN:

152358

Hom.:

Cov.:

AF XY:

0.0000268

AC XY:

AN XY:

74504

show subpopulations

Gnomad4 AFR

AF:

0.0000240

Gnomad4 AMR

AF:

0.0000653

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.000945

Alfa

AF:

0.000166

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.000107

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Apr 28, 2017	This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center	Mar 26, 2024	- -

Lynch syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jul 29, 2024

This missense variant replaces alanine with serine at codon 31 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 not been reported in individuals affected with MLH1-related disorders in the literature. This variant has been identified in 22/282520 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. -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Mar 31, 2022

The MLH1 c.91_92delinsTG; p.Ala31Cys variant (rs63749994) is reported in the medical literature in several individuals with Lynch syndrome (Auclair 2006, Drost 2010, Hardt 2011), some of whom also carried the MLH1 c.1360G>C; p.Gly454Arg variant of uncertain significance (Auclair 2006, Hardt 2011). The c.91_92delGCinsTG variant is also reported in ClinVar (Variation ID: 90442), and is found in the general population with an overall allele frequency of 0.0078% (22/282508 alleles) in the Genome Aggregation Database. The alanine at position 31 is highly conserved and computational algorithms (PolyPhen2, SIFT) predict a deleterious effect. This variant has reduced in vitro mismatch repair activity when compared to wild type, but still maintains significantly higher activity than known deleterious variants (Drost 2010). However, given the limited clinical and functional data, the significance of this variant is uncertain at this time. References: Auclair et al. Systematic mRNA analysis for the effect of MLH1 and MSH2 missense and silent mutations on aberrant splicing. Hum Mutat. 2006 ;27(2):145-154. PMID: 16395668. Drost et al. A cell-free assay for the functional analysis of variants of the mismatch repair protein MLH1. Hum Mutat. 2010;31(3):247-253. PMID: 20020535. Hardt et al. Missense variants in hMLH1 identified in patients from the German HNPCC consortium and functional studies. Fam Cancer. 2011;10(2):273-284. PMID: 21404117. -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 13, 2019

The p.A31S variant (also known as c.91G>T), located in coding exon 1 of the MLH1 gene, results from a G to T substitution at nucleotide position 91. The alanine at codon 31 is replaced by serine, 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. In addition, this alteration is predicted to be deleterious by MAPP-MMR in silico analyses (Chao EC et al. Hum. Mutat. 2008 Jun;29:852-60). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Hereditary nonpolyposis colorectal neoplasms

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Sep 03, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.47

BayesDel_addAF

Pathogenic

0.37

BayesDel_noAF

Pathogenic

0.60

CADD

Pathogenic

DANN

Uncertain

1.0

DEOGEN2

Pathogenic

0.90

Eigen

Pathogenic

0.74

Eigen_PC

Pathogenic

0.77

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Pathogenic

0.98

M_CAP

Pathogenic

0.64

MetaRNN

Pathogenic

0.94

MetaSVM

Uncertain

0.42

MutationAssessor

Pathogenic

4.3

PrimateAI

Uncertain

0.75

PROVEAN

Uncertain

-2.5

REVEL

Pathogenic

0.93

Sift

Pathogenic

0.0

Sift4G

Uncertain

0.045

Polyphen

0.99

Vest4

0.75

MutPred

0.77

Loss of ubiquitination at K33 (P = 0.0795);

MVP

0.98

MPC

0.38

ClinPred

0.88

GERP RS

6.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.6

Varity_R

0.96

gMVP

0.64

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