rs587778920

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM1PM4_Supporting

The NM_000249.4(MLH1):c.1500_1502del(p.Ile501del) variant causes a inframe deletion change. The variant allele was found at a frequency of 0.00000434 in 1,614,054 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. I500I) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

MLH1
NM_000249.4 inframe_deletion

Scores

Not classified

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts P:1U:8

Conservation

PhyloP100: 6.20

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 Uncertain_significance. Variant got 3 ACMG points.

PM1

In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 17 uncertain in NM_000249.4

PM4

Nonframeshift variant in NON repetitive region in NM_000249.4. Strenght limited to Supporting due to length of the change: 1aa.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4 linkuse as main transcript	c.1500_1502del	p.Ile501del	inframe_deletion	13/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8 linkuse as main transcript	c.1500_1502del	p.Ile501del	inframe_deletion	13/19	1	NM_000249.4	P1	P40692-1

Frequencies

GnomAD3 genomes

AF:

0.0000131

AC:

AN:

152172

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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

GnomAD3 exomes

AF:

0.0000119

AC:

AN:

251478

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135906

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000867

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000342

AC:

AN:

1461882

Hom.:

AF XY:

0.00000138

AC XY:

AN XY:

727242

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000894

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:

0.0000131

AC:

AN:

152172

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74334

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.0000151

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1Uncertain:8

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Hereditary cancer-predisposing syndrome

Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Nov 13, 2019	This variant causes an in-frame deletion of 1 amino acid of the MLH1 protein. Splice site prediction tools suggest that this variant may not impact RNA splicing. Functional studies showed that this variant protein have wild-type expression level and DNA mismatch repair activity (PMID 29520894). This variant has been reported in 1 individual affected with Lynch Syndrome (PMID 29520894, 28874130). This variant has been identified in 3/251478 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. -
Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Jan 13, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 14, 2024	The c.1500_1502delCAT variant (also known as p.I501del) is located in coding exon 13 of the MLH1 gene. This variant results from an in-frame CAT deletion at nucleotide positions 1500 to 1502. This results in the in-frame deletion of an isoleucine at codon 501. This alteration has been reported in a Brazilian female with colorectal cancer at age 60 (Rossi BM et al. Ann Surg Oncol, 2002 Jul;9:555-61). This alteration was identified in an individual diagnosed with an adrenocortical tumor who also carries a TP53 mutation, Arg337His (Brondani VB et al. Cancers (Basel), 2020 Mar;12). This alteration was also detected once in a cohort of 1663 Brazilian breast cancer patients who underwent hereditary multigene panel testing (Guindalini RSC et al. Sci Rep, 2022 Mar;12:4190). Of note, this alteration is also designated as c.1499_1501delTCA in published literature. This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive (Choi Y et al. PLoS ONE. 2012; 7(10):e46688). Based on the available evidence, the clinical significance of this alteration remains unclear. -

Colorectal cancer, hereditary nonpolyposis, type 2

Pathogenic:1Uncertain:1

Pathogenic, flagged submission	clinical testing	Center for Human Genetics, Inc, Center for Human Genetics, Inc	Nov 01, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mendelics	May 28, 2019	- -

not provided

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 06, 2023	In-frame deletion of 1 amino acids in a non-repeat region; In silico analysis supports a deleterious effect on protein structure/function; Located in the critical region of interaction with EXO1 and PMS2/MLH2/PMS1 (Plotz et al., 2003; Kosinski et al., 2010; Andersen et al., 2012); Published functional studies demonstrate no damaging effect: no significant effect on protein expression levels or mismatch repair activity (Kger et al., 2018); Observed in individuals with colorectal cancer or breast cancer, and co-observed with a pathogenic TP53 variant in a pediatric patient with adrenocortical neoplasm (Rossi et al., 2002; Brondani et al., 2020; Guindalini et al., 2022); This variant is associated with the following publications: (PMID: 24344984, 12095971, 28874130, 22753075, 12799449, 20533529, 35264596, 29520894, 32156018) -
Uncertain significance, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	May 15, 2017	- -

Lynch syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Apr 27, 2023

This variant causes an in-frame deletion of 1 amino acid of the MLH1 protein. Splice site prediction tools suggest that this variant may not impact RNA splicing. Functional studies showed that this variant protein have wild-type expression level and DNA mismatch repair activity (PMID 29520894). This variant has been reported in 1 individual affected with Lynch Syndrome (PMID 29520894, 28874130). This variant has been identified in 3/251478 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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 22, 2024

This variant, c.1500_1502del, results in the deletion of 1 amino acid(s) of the MLH1 protein (p.Ile501del), but otherwise preserves the integrity of the reading frame. This variant is present in population databases (rs753409799, gnomAD 0.006%). This variant has been observed in individual(s) with an adrenocortical tumor and/or Lynch syndrome (PMID: 12095971, 28874130, 29520894, 32156018). This variant is also known as c.1499-1501delTCA. ClinVar contains an entry for this variant (Variation ID: 89755). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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

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

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