rs781335662

Variant names:

• chr3-37025853-A-G
• rs781335662
• NM_000249.4:c.1255A>G

Your query was ambiguous. Multiple possible variants found:

• chr3-37025853-A-G
• chr3-37025853-A-T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM1 BP4_Strong

The NM_000249.4(MLH1):​c.1255A>G​(p.Ile419Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000229 in 1,613,844 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I419T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.000025 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:7
• Conservation: PhyloP100: 0.00600
• Publications: 2 publications found

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 Gene-Disease associations (from GenCC):

• Lynch syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
• Lynch syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
• Muir-Torre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet
• mismatch repair cancer syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
• Lynch syndrome 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• ovarian cancer

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• malignant pancreatic neoplasm

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• rhabdomyosarcoma

  Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
• prostate cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• breast cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
• hereditary breast carcinoma

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 41 uncertain in NM_000249.4
• BP4: Computational evidence support a benign effect (MetaRNN=0.0504106).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1255A>G	p.Ile419Val	missense_variant	Exon 12 of 19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.1255A>G	p.Ile419Val	missense_variant	Exon 12 of 19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151950 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000199 AC: 5 AN: 251348 AF XY: 0.0000294

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 FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000246 AC: 36 AN: 1461894 Hom.: 0 Cov.: 34 AF XY: 0.0000275 AC XY: 20 AN XY: 727248

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.000151 AC: 13 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.0000198 AC: 22 AN: 1112012

Other (OTH) AF: 0.0000166 AC: 1 AN: 60396

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151950 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74198

African (AFR) AF: 0.00 AC: 0 AN: 41352

American (AMR) AF: 0.00 AC: 0 AN: 15248

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3464

East Asian (EAS) AF: 0.00 AC: 0 AN: 5186

South Asian (SAS) AF: 0.000207 AC: 1 AN: 4820

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10568

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67996

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.00 Hom.: 0

ExAC AF: 0.0000330 AC: 4

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lynch syndrome Uncertain:2

Jul 13, 2021

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 28, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces isoleucine with valine at codon 419 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 hereditary cancer in the literature. This variant has been identified in 5/251348 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 cancer-predisposing syndrome Uncertain:2

Mar 08, 2021

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces isoleucine with valine at codon 419 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 hereditary cancer in the literature. This variant has been identified in 5/251348 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. -

Oct 30, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.I419V variant (also known as c.1255A>G), located in coding exon 12 of the MLH1 gene, results from an A to G substitution at nucleotide position 1255. The isoleucine at codon 419 is replaced by valine, an amino acid with highly similar properties. This amino acid position is poorly conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the available evidence, the clinical significance of this variant remains unclear. -

not specified Uncertain:1

Mar 04, 2025

Center for Genomic Medicine, Rigshospitalet, Copenhagen University Hospital

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

May 08, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Observed in an individual with triple negative breast cancer (Liu et al., 2017); This variant is associated with the following publications: (PMID: 28135048, 22753075) -

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Apr 22, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 419 of the MLH1 protein (p.Ile419Val). This variant is present in population databases (rs781335662, gnomAD 0.01%). This missense change has been observed in individual(s) with breast cancer (PMID: 28135048). ClinVar contains an entry for this variant (Variation ID: 455380). 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 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	Benign	0.058
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.24
CADD	Benign	5.0
DANN	Benign	0.85
DEOGEN2	Benign	0.27	T;.;.;.;.;.
Eigen	Benign	-1.3
Eigen_PC	Benign	-1.3
FATHMM_MKL	Benign	0.040	N
LIST_S2	Benign	0.48	T;T;.;.;.;T
M_CAP	Benign	0.035	D
MetaRNN	Benign	0.050	T;T;T;T;T;T
MetaSVM	Benign	-0.61	T
MutationAssessor	Benign	-0.55	N;.;.;.;.;.
PhyloP100		0.0060
PrimateAI	Benign	0.23	T
PROVEAN	Benign	0.23	N;N;N;N;N;N
REVEL	Uncertain	0.44
Sift	Benign	0.39	T;T;T;T;T;T
Sift4G	Benign	0.30	T;T;T;T;T;T
Polyphen		0.0	B;.;.;.;.;.
Vest4		0.18
MutPred		0.16		Loss of catalytic residue at I419 (P = 0.087);.;.;.;.;.;
MVP		0.87
MPC		0.057
ClinPred		0.023	T
GERP RS		-3.1
PromoterAI		-0.012	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.012
gMVP		0.12
Mutation Taster		=90/10	polymorphism

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

Other links and lift over

dbSNP: rs781335662; hg19: chr3-37067344;