rs63750465

Variant names:

• chr3-37004441-C-A
• rs63750465
• NM_000249.4:c.347C>A

Your query was ambiguous. Multiple possible variants found:

• chr3-37004441-C-A
• chr3-37004441-C-G
• chr3-37004441-C-T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM1 PP3_Moderate

The NM_000249.4(MLH1):​c.347C>A​(p.Thr116Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000136 in 1,613,986 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. T116A) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.000033 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000012 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8 B:2
• Conservation: PhyloP100: 7.59
• Publications: 8 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: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 11 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 36 uncertain in NM_000249.4
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.882

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4	c.347C>A	p.Thr116Lys	missense_variant	Exon 4 of 19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.347C>A	p.Thr116Lys	missense_variant	Exon 4 of 19	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes AF: 0.0000329 AC: 5 AN: 152178 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000965

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

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: 0.00

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.00000796 AC: 2 AN: 251410 AF XY: 0.0000147

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: 0.0000116 AC: 17 AN: 1461808 Hom.: 0 Cov.: 30 AF XY: 0.00000963 AC XY: 7 AN XY: 727206

African (AFR) AF: 0.0000299 AC: 1 AN: 33480

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53416

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.0000135 AC: 15 AN: 1111960

Other (OTH) AF: 0.0000166 AC: 1 AN: 60386

GnomAD4 genome AF: 0.0000329 AC: 5 AN: 152178 Hom.: 0 Cov.: 32 AF XY: 0.0000404 AC XY: 3 AN XY: 74330

African (AFR) AF: 0.0000965 AC: 4 AN: 41436

American (AMR) AF: 0.0000655 AC: 1 AN: 15272

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 68048

Other (OTH) AF: 0.00 AC: 0 AN: 2090

Alfa AF: 0.0000329 Hom.: 0

Bravo AF: 0.0000227

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:2

Dec 02, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MLH1 c.347C>A (p.Thr116Lys) variant has been reported in the published literature in individuals affected with colorectal cancer (PMID: 18561205 (2008), 30998989 (2019)). Functional studies reported this variant had a neutral effect on MLH1 splicing (PMID: 18561205 (2008)) and protein function (PMID: 30998989 (2019)). The frequency of this variant in the general population, 0.000011 (3/282818 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded predictions that this variant is damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -

Sep 20, 2021

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Observed in individuals with MLH1-related cancers (Tournier 2008, Bouvet 2019); Published functional studies demonstrate no damaging effect: intact splicing and moderate cell survival after DNA damage (Tournier 2008, Bouvet 2019); Not observed at a significant frequency in large population cohorts (Lek 2016); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 22788692, 26333163, 22753075, 18561205, 12202775, 25871441, 23729658, 30998989) -

Hereditary cancer-predisposing syndrome Uncertain:2

May 24, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces threonine with lysine at codon 116 of the MLH1 protein. Computational prediction tool suggests that this variant may have deleterious impact on protein structure and function. A functional study has demonstrated the mutant protein exhibits normal function in a methylation tolerance-based functional assay (PMID: 30998989). This variant has been reported in an individual affected with or suspected of having Lynch syndrome (PMID: 18561205). This variant has been identified in 3/282818 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. -

Jul 11, 2024

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T116K variant (also known as c.347C>A), located in coding exon 4 of the MLH1 gene, results from a C to A substitution at nucleotide position 347. The threonine at codon 116 is replaced by lysine, an amino acid with similar properties. This alteration has been reported in one individual either fulfilling Amsterdam II criteria or having a tumor demonstrating microsatellite instability (Tournier I et al. Hum Mutat, 2008 Dec;29:1412-24). This variant was also identified in a cohort of 3,579 African males diagnosed with prostate cancer who underwent multi-gene panel testing of 19 DNA repair and cancer predisposition genes (Matejcic M et al. JCO Precis Oncol, 2020 Jan;4:32-43). This variant has been identified in an individual diagnosed with colorectal cancer at 22 (Vibert R et al. Eur J Hum Genet, 2023 Sep;31:1078-1082). The T116K variant demonstrated evidence supporting benign in a methylation tolerance-based functional assay (Bouvet D et al. Gastroenterology, 2019 08;157:421-431). 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. -

Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:1 Benign:1

Nov 02, 2016

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Nov 19, 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]. -

not specified Uncertain:1

Nov 09, 2017

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: The MLH1 c.347C>A (p.Thr116Lys) variant causes a missense change located in the Histidine kinase/HSP90-like ATPasedomain of the protein (InterPro) involving the alteration of a non-conserved nucleotide. 4/4 in silico tools predict a damaging outcome for this variant (SNPsandGO not captured due to low reliability index). This variant was found in 3/277164 control chromosomes (gnomAD) at a frequency of 0.0000108, which does not exceed the estimated maximal expected allele frequency of a pathogenic MLH1 variant (0.0007105). Tournier_2008 found this variant to have no effect on splicing in an ex vivo splicing assay. In addition, multiple clinical diagnostic laboratories/reputable databases classified this variant as uncertain significance. Because of the absence of clinical information and the lack of functional studies, the variant is classified as a variant of uncertain significance (VUS). -

Muir-Torré syndrome;C1333991:Colorectal cancer, hereditary nonpolyposis, type 2;C5399763:Mismatch repair cancer syndrome 1 Uncertain:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Lynch syndrome Uncertain:1

Jun 09, 2024

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 threonine with lysine at codon 116 of the MLH1 protein. Computational prediction tool suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). A functional study has shown the mutant protein to exhibit normal function in a methylation tolerance-based functional assay (PMID: 30998989). This variant has been reported in an individual affected with or suspected of having Lynch syndrome (PMID: 18561205). This variant has been identified in 3/282818 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 Benign:1

Jan 22, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.85
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.39
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D;.;T
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;D
M_CAP	Uncertain	0.19	D
MetaRNN	Pathogenic	0.88	D;D;D
MetaSVM	Uncertain	0.75	D
MutationAssessor	Uncertain	2.0	M;.;.
PhyloP100		7.6
PrimateAI	Pathogenic	0.83	D
PROVEAN	Uncertain	-4.0	D;D;D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0070	D;D;D
Sift4G	Uncertain	0.035	D;D;D
Polyphen		0.99	D;.;.
Vest4		0.77
MutPred		0.70		Loss of ubiquitination at K118 (P = 0.0288);.;.;
MVP		0.96
MPC		0.41
ClinPred		0.98	D
GERP RS		6.0
Varity_R		0.72
gMVP		0.90
Mutation Taster		=21/79	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
Splicevardb		1.0
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

Other links and lift over

dbSNP: rs63750465; hg19: chr3-37045932;