rs63751275

chr3-37048973-C-Achr3-37048973-C-Gchr3-37048973-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. PM2 PP3 BP6

The NM_000249.4(MLH1):c.2059C>A(p.Arg687=) variant causes a synonymous change. The variant allele was found at a frequency of 0.000000684 in 1,461,818 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. R687R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MLH1 NM_000249.4 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:3
• Conservation: PhyloP100: 4.98

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• BP6: Variant 3-37048973-C-A is Benign according to our data. Variant chr3-37048973-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 483572.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4	c.2059C>A	p.Arg687=	synonymous_variant	18/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8	c.2059C>A	p.Arg687=	synonymous_variant	18/19	1	NM_000249.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461818 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727214

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 Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Jul 28, 2023	The c.2059C>A variant (also known as p.R687R), located in coding exon 18 of the MLH1 gene, results from a C to A substitution at nucleotide position 2059. This nucleotide substitution does not change the arginine at codon 687. This nucleotide position is not well conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Sep 04, 2020	- -

Lynch syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Jun 26, 2023

- -

Hereditary nonpolyposis colorectal neoplasms Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Apr 23, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.24
Cadd	Benign	21
Dann	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.57		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.57		Position offset: 2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs63751275; hg19: chr3-37090464;