rs63750547

Positions:

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1PM2PP3_Strong

The NM_000249.4(MLH1):c.887T>C(p.Leu296Ser) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,614,020 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. 1/1 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense, splice_region

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:1

Conservation

PhyloP100: 7.64

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 Likely_pathogenic. Variant got 8 ACMG points.

PM1

In a strand (size 7) in uniprot entity MLH1_HUMAN there are 8 pathogenic changes around while only 3 benign (73%) in NM_000249.4

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.981

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.887T>C	p.Leu296Ser	missense_variant, splice_region_variant	11/19	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.887T>C	p.Leu296Ser	missense_variant, splice_region_variant	11/19	1	NM_000249.4	ENSP00000231790	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152164

Hom.:

Cov.:

show subpopulations

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:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000398

AC:

AN:

251430

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135894

show subpopulations

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 SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000879

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461856

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

727228

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

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

AF:

0.00000657

AC:

AN:

152164

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74342

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

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

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

EpiCase

AF:

0.0000545

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8Benign: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.	Mar 10, 2023	This variant is considered likely benign. Homozygosity for this variant has been confirmed in one or more individuals lacking clinical features consistent with gene-specific recessive disease, indicating that this variant is unlikely to be pathogenic. -
Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Sep 07, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Feb 28, 2018	- -

Hereditary cancer-predisposing syndrome

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 13, 2024	The p.L296S variant (also known as c.887T>C), located in coding exon 11 of the MLH1 gene, results from a T to C substitution at nucleotide position 887. The leucine at codon 296 is replaced by serine, an amino acid with dissimilar properties. This alteration has been reported in a patient with a personal history of invasive breast cancer before age 40 (Rummel SK et al. Breast Cancer Res. Treat., 2017 Aug;164:593-601). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Feb 06, 2023	This missense variant replaces leucine with serine at codon 296 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 individuals affected with breast cancer (PMID: 28503720), basal cell carcinoma (PMIDL 30089731), and unspecified cancer suspected of Lynch syndrome (PMID: 31391288). This variant has been identified in 1/251430 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 specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Feb 20, 2024

Variant summary: MLH1 c.887T>C (p.Leu296Ser) results in a non-conservative amino acid change located in the S5 domain 2-like fold (IPR013507) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. This variant is located close to a splice-site, therefore might also affect splicing. Consensus agreement among computation tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 2.6e-06 in 775556 control chromosomes (gnomAD v4.0). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.887T>C has been reported in the literature in individuals affected with various tumor phenotypes, including tumor(s) that belong to the Lynch syndrome (LS) tumor spectrum (e.g. Li_2020), and also other tumors that are not part of the LS tumor spectrum (e.g. Cho_2018, Rummel_2017). These reports do not provide unequivocal conclusions about association of the variant with Hereditary Nonpolyposis Colorectal Cancer. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. ClinVar contains an entry for this variant (Variation ID: 232668). 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

Nov 30, 2023

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 20, 2023

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Observed in individuals with a personal and/or family history of MLH1-related cancers and other cancers in published literature (Rummel et al., 2017; Cho et al., 2018; Li et al., 2020); This variant is associated with the following publications: (PMID: 28503720, 30089731, 31391288, 22753075) -

Hereditary nonpolyposis colorectal neoplasms

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 27, 2023

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. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. ClinVar contains an entry for this variant (Variation ID: 232668). This missense change has been observed in individual(s) with breast cancer, basal cell carcinoma (PMID: 28503720, 30089731). This variant is present in population databases (rs63750547, gnomAD 0.0009%). This sequence change replaces leucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 296 of the MLH1 protein (p.Leu296Ser). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.98

BayesDel_addAF

Pathogenic

0.47

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

DANN

Benign

0.89

DEOGEN2

Pathogenic

0.89

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

Eigen

Pathogenic

1.0

Eigen_PC

Pathogenic

0.95

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Pathogenic

0.98

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

M_CAP

Pathogenic

0.35

MetaRNN

Pathogenic

0.98

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

MetaSVM

Uncertain

0.77

MutationAssessor

Pathogenic

4.4

H;.;.;.;.;.;.

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Pathogenic

0.81

PROVEAN

Pathogenic

-5.6

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

REVEL

Pathogenic

0.97

Sift

Pathogenic

0.0

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

Sift4G

Pathogenic

0.0010

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

Polyphen

1.0

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

Vest4

0.96

MutPred

0.91

Gain of disorder (P = 0.0163);.;.;.;.;.;.;

MVP

0.97

MPC

0.47

ClinPred

0.99

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.0

Varity_R

0.97

gMVP

0.93

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