rs267607824

chr3-37025726-T-C

Variant summary

Our verdict is Benign. Variant got -17 ACMG points: 0P and 17B. BP4_Strong BP6_Very_Strong BP7 BS1

The NM_000249.4(MLH1):c.1128T>C(p.Asp376=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000353 in 1,613,086 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 Benign (★★★).

• Frequency:
  • Genomes: 𝑓 0.000046 (0 hom., cov: 31)
  • Exomes 𝑓: 0.000034 (0 hom.)
• Consequence: MLH1 NM_000249.4 synonymous
• Clinical Significance: Benign reviewed by expert panel B:12
• Conservation: PhyloP100: -0.0540

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 Benign. Variant got -17 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.68).
• BP6: Variant 3-37025726-T-C is Benign according to our data. Variant chr3-37025726-T-C is described in ClinVar as [Benign]. Clinvar id is 89643.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr3-37025726-T-C is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=-0.054 with no splicing effect.
• BS1: Variant frequency is greater than expected in population eas. gnomad4 allele frequency = 0.0000462 (7/151360) while in subpopulation EAS AF= 0.00136 (7/5132). AF 95% confidence interval is 0.00064. There are 0 homozygotes in gnomad4. There are 3 alleles in male gnomad4 subpopulation. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MLH1	NM_000249.4	c.1128T>C	p.Asp376=	synonymous_variant	12/19	ENST00000231790.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MLH1	ENST00000231790.8	c.1128T>C	p.Asp376=	synonymous_variant	12/19	1	NM_000249.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000462 AC: 7 AN: 151360 Hom.: 0 Cov.: 31

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00136

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: 0.0000676 AC: 17 AN: 251440 Hom.: 0 AF XY: 0.0000589 AC XY: 8 AN XY: 135896

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000924

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: 0.0000342 AC: 50 AN: 1461726 Hom.: 0 Cov.: 34 AF XY: 0.0000330 AC XY: 24 AN XY: 727164

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00126

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000462 AC: 7 AN: 151360 Hom.: 0 Cov.: 31 AF XY: 0.0000406 AC XY: 3 AN XY: 73828

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00136

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000378

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:12

Revision: reviewed by expert panel

Submissions by phenotype

Hereditary cancer-predisposing syndrome Benign:3

Likely benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Mar 30, 2016	- -
Likely benign, criteria provided, single submitter	curation	Sema4, Sema4	Aug 25, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 19, 2015	This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

not specified Benign:2

Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 13, 2018	Variant summary: MLH1 c.1128T>C alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The observed variant frequency within East Asian control individuals in the gnomAD database is approximately 1.55 fold of the estimated maximal expected allele frequency for a pathogenic variant in MLH1 causing Lynch Syndrome phenotype (0.00071), strongly suggesting that the variant is a benign polymorphism found primarily in populations of East Asian origin. c.1128T>C has been reported in the literature in individuals affected with Lynch Syndrome, however 9 out of the reported 18 families with c.1128T>C (Asp376) also had pathogenic mutations in MLH1, MSH2 or MSH6 (Shin_2004), strongly supporting the benign nature of this variant. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 15, 2015	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Colorectal cancer, hereditary nonpolyposis, type 2 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Counsyl	Apr 28, 2016	- -
Benign, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Mar 15, 2023	This variant is considered benign. This variant is a silent/synonymous amino acid change and it is not expected to impact splicing. -

Lynch syndrome Benign:2

Benign, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	MAF >1% -
Likely benign, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Nov 30, 2023	- -

not provided Benign:2

Benign, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	May 23, 2018	- -
Likely benign, no assertion criteria provided	clinical testing	Department of Pathology and Laboratory Medicine, Sinai Health System	-	MLH1, EXON 12, c.1128T>C, p.Asp376=, Heterozygous, Likely benign The MLH1 p.Asp376= variant was identified in 18 of 282 proband chromosomes (frequency: 0.06) from individuals or families with Lynch syndrome and was present in 12 of 368 control chromosomes (frequency: 0.03) from healthy individuals (Shin 2004). The variant was also identified in the following databases: dbSNP (ID: rs267607824) as "With Likely benign allele", ClinVar (3x likely benign, 3x benign including review by expert panel InSiGHT), Clinvitae, Mismatch Repair Genes Variant Database, and the Insight Hereditary Tumors Database (1x, not pathogenic). The variant was not identified in GeneInsight-COGR, Cosmic, MutDB, UMD-LSDB, or the Zhejiang Colon Cancer Database. The variant was identified in control databases in 20 of 276984 chromosomes at a frequency of 0.00007 (Genome Aggregation Database Feb 27, 2017). Breakdown of the observations by population include East Asian in 20 of 18854 chromosomes (freq: 0.001), while the variant was not observed in the African, Other, Latino, European, Ashkenazi Jewish, Finnish, and South Asian populations. A study by Shin 2004 found no statistically significant difference in frequency between Lynch syndrome patients and controls for this variant, and listed it as a polymorphism. The p.Asp376= variant is not expected to have clinical significance because it does not result in a change of amino acid and is not located in a known consensus splice site. In addition, in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -

Hereditary nonpolyposis colorectal neoplasms Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 31, 2024

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
Cadd	Benign	8.8
Dann	Benign	0.50

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs267607824; hg19: chr3-37067217;