rs267607788

Positions:

• chr3-37017501-T-G

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 10P and 1B. PM2 PP5_Very_Strong BP4

The NM_000249.4(MLH1):​c.791-5T>G variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MLH1 NM_000249.4 splice_region, intron
• Scores: Splicing: ADA: 0.7810
• Clinical Significance: Pathogenic reviewed by expert panel P:7
• Conservation: PhyloP100: 4.04

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 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 3-37017501-T-G is Pathogenic according to our data. Variant chr3-37017501-T-G is described in ClinVar as [Pathogenic]. Clinvar id is 90374.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37017501-T-G is described in Lovd as [Pathogenic]. Variant chr3-37017501-T-G is described in Lovd as [Likely_pathogenic].
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.68). . Strength limited to SUPPORTING due to the PP5.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MLH1	NM_000249.4	c.791-5T>G		splice_region_variant, intron_variant		ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.791-5T>G		splice_region_variant, intron_variant		1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:7

Revision: reviewed by expert panel

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Human Genetics Bochum, Ruhr University Bochum	Nov 26, 2021	ACMG criteria used to clasify this variant: PVS1, PM2, PS3 -
Pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, University of Leipzig Medical Center	Jan 01, 2019	- -

Lynch syndrome Pathogenic:2

Pathogenic, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	Variant causes splicing aberration: full inactivation of variant allele. -
Pathogenic, criteria provided, single submitter	clinical testing	Mendelics	Jul 02, 2018	- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Oct 01, 2022

MLH1: PM2, PS3:Moderate, PP4, PS4:Supporting -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 26, 2023

This variant has been observed in individuals with Lynch syndrome (PMID: 16395668, 18561205; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 9 of the MLH1 gene. It does not directly change the encoded amino acid sequence of the MLH1 protein. RNA analysis indicates that this variant induces altered splicing and may result in an absent or disrupted protein product. ClinVar contains an entry for this variant (Variation ID: 90374). For these reasons, this variant has been classified as Pathogenic. Studies have shown that this variant alters mRNA splicing and is expected to lead to the loss of protein expression (PMID: 16395668, 18561205, 26761715). -

Hereditary cancer-predisposing syndrome Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Apr 03, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
CADD	Benign	17
DANN	Benign	0.84
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.78
dbscSNV1_RF	Benign	0.63
SpliceAI score (max)		0.18		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

Other links and lift over

dbSNP: rs267607788; hg19: chr3-37058992;