rs63750016

chr3-37047553-C-Achr3-37047553-C-Gchr3-37047553-C-T

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_000249.4(MLH1):c.1766C>A(p.Ala589Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A589F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 31)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Likely pathogenic reviewed by expert panel P:2
• Conservation: PhyloP100: 7.70

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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 15 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.952
• PP5: Variant 3-37047553-C-A is Pathogenic according to our data. Variant chr3-37047553-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 89884.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37047553-C-A is described in Lovd as [Likely_pathogenic]. Variant chr3-37047553-C-A is described in Lovd as [Pathogenic]. Variant chr3-37047553-C-A is described in Lovd as [Benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4	c.1766C>A	p.Ala589Asp	missense_variant	16/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8	c.1766C>A	p.Ala589Asp	missense_variant	16/19	1	NM_000249.4	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: reviewed by expert panel

Submissions by phenotype

Colorectal cancer, hereditary nonpolyposis, type 2 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Jul 21, 2023

This variant is considered likely pathogenic. Functional studies indicate this variant impacts protein function [PMID: 20020535, 31784484]. This variant has been reported in multiple individuals with clinical features of gene-specific disease [PMID: 16083711, 21404117]. This variant is expected to disrupt protein structure [Myriad internal data]. -

Lynch syndrome Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

International Society for Gastrointestinal Hereditary Tumours (InSiGHT)

Jun 21, 2019

Abrogated function (reduced expression in 2 independent assays) & 2 MSI-H tumours -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.51	D
BayesDel_noAF	Pathogenic	0.50
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.93	D;.;.;.;.;.
Eigen	Uncertain	0.63
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Pathogenic	0.97	D;D;.;.;.;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Pathogenic	0.95	D;D;D;D;D;D
MetaSVM	Uncertain	0.42	D
MutationAssessor	Pathogenic	3.6	H;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Pathogenic	0.80	T
PROVEAN	Pathogenic	-5.0	D;D;D;D;D;D
REVEL	Pathogenic	0.92
Sift	Uncertain	0.0030	D;D;D;D;D;D
Sift4G	Uncertain	0.0060	D;D;D;D;D;D
Polyphen		1.0	D;.;.;.;.;.
Vest4		0.88
MutPred		0.81		Loss of sheet (P = 7e-04);.;.;.;.;.;
MVP		0.97
MPC		0.48
ClinPred		1.0	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.97
gMVP		0.95

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

Publications

LitVar

Other links and lift over

dbSNP: rs63750016; hg19: chr3-37089044;