3-37028891-T-C

Variant names:

• chr3-37028891-T-C
• rs63749909
• NM_000249.4:c.1517T>C

Variant summary

Our verdict is Pathogenic. The variant received 13 ACMG points: 13P and 0B. PS3 PM1 PM2 PP3_Strong PP5

The NM_000249.4(MLH1):​c.1517T>C​(p.Val506Ala) variant causes a missense change. The variant allele was found at a frequency of 0.00000658 in 152,072 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). ClinVar reports functional evidence for this variant: "SCV000212722: Multiple yeast-based functional studies of this variant have demonstrated reduced binding of the V506A hMLH1 protein with hPMS2 when compared to wild-type hMLH1 (Guerrette S et al. J. Biol. Chem. 1999 Mar 5" and additional evidence is available in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V506I) has been classified as Uncertain significance. The gene MLH1 is included in the ClinGen Criteria Specification Registry.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:11 U:1
• Conservation: PhyloP100: 6.20
• Publications: 19 publications found

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 Gene-Disease associations (from GenCC):

• Lynch syndrome

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet, G2P
• Lynch syndrome 2

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
• Muir-Torre syndrome

  Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet
• mismatch repair cancer syndrome 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics, G2P, ClinGen
• Lynch syndrome 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
• ovarian cancer

  Inheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
• malignant pancreatic neoplasm

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• rhabdomyosarcoma

  Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
• prostate cancer

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• breast cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
• hereditary breast carcinoma

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Specifications for MLH1 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Our verdict: Pathogenic. The variant received 13 ACMG points.

• PS3: PS3 evidence extracted from ClinVar submissions: SCV000212722: Multiple yeast-based functional studies of this variant have demonstrated reduced binding of the V506A hMLH1 protein with hPMS2 when compared to wild-type hMLH1 (Guerrette S et al. J. Biol. Chem. 1999 Mar 5;274:6336-41; Kondo E et al. Cancer Res. 2003 Jun;63:3302-8; Shimodaira H et al. Nat. Genet. 1998 Aug;19:384-9). Further, multiple functional studies where cell lines were transfected with this alteration have been shown to exhibit reduced MLH1 expression; however, in vitro functional assays showed that mismatch repair activity was comparable to wild-type (Hinrichsen I et al. Clin. Cancer Res. 2013 May;19:2432-41; Takahashi M et al. Cancer Res. 2007 May;67:4595-604).; SCV000911974: Functional studies have shown that this variant reduced MLH1 protein expression (PMID: 9697702, 17510385, 23403630), disrupted PMS2 and EXO1 binding activity (PMID: 10037723, 12810663), and reduced dominant mutator effect (PMID: 9697702, 17510385).; SCV000211106: "Published functional studies demonstrate a damaging effect with respect to a dominant mutator effect, MLH1 expression, and PMS2 and EXO1 binding, while studies assessing mismatch repair activity show results comparable to wild-type (PMID: 9697702, 10037723, 12810663, 17510385, 23403630)"; SCV000601359: "Some indicate a detrimental effect after observing significantly reduced MLH1 protein expression (PMIDs: 9697702 (1998), 17510385 (2007), 23403630 (2013), 31697235 (2019), 36054288 (2022)) and reduced PMS2 interaction (PMIDs: 10037723 (1999), 12810663 (2003), 19250818 (2009))."; SCV000885704: "In vitro functional analyses demonstrate reduced protein expression, but close to wild-type mismatch repair activity (Hinrichsen 2013, Takahashi 2007). Additionally, yeast two hybrid assays have demonstrated reduced functional outputs (Kondo 2003, Shimodaira 1998)."; SCV000543586: Experimental studies have shown that this missense change affects MLH1 function (PMID: 9697702, 10037723, 12810663, 17510385, 23403630).; SCV000919651: "In in vitro functional studies, the variant showed reduced MLH1 expression and altered binding to PMS2 and EXO1, but mismatch repair (MMR) activity close to wild type (Shimodaira_1998, Guerrette_1999, Takahashi_2007, Hinrichsen_2013)."; SCV004111858: "In vitro experimental studies suggest this variant leads to reduced binding to hPMS2, reduced MMR activity, and reduced protein expression (Guerrette et al. 1999. PubMed ID: 10037723; Figure 1, Hinrichsen et al. 2013. PubMed ID: 23403630; Table S1, Ou et al. 2007. PubMed ID: 17594722; Table 1, Takahashi et al. 2007. PubMed ID: 17510385). In vivo experimental studies suggest this variant reduces binding to EXO1 and inactivates the dominant negative phenotype of hMLH1 in some strains of yeast (Table 1, Figure 3b, Shimodaira et al. 1998. PubMed ID: 9697702; Table 1, Kondo et al 2003. PubMed ID: 12810663; Table 1, Takahashi et al. 2007. PubMed ID: 17510385)."
• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 38 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.941
• PP5: Variant 3-37028891-T-C is Pathogenic according to our data. Variant chr3-37028891-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 89757.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000249.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH1	NM_000249.4	MANE Select	c.1517T>C	p.Val506Ala	missense	Exon 13 of 19	NP_000240.1	P40692-1
	MLH1	NM_001354628.2		c.1517T>C	p.Val506Ala	missense	Exon 13 of 18	NP_001341557.1	A0A087WX20
	MLH1	NM_001354629.2		c.1418T>C	p.Val473Ala	missense	Exon 12 of 18	NP_001341558.1	A0AAQ5BGZ2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH1	ENST00000231790.8	TSL:1 MANE Select	c.1517T>C	p.Val506Ala	missense	Exon 13 of 19	ENSP00000231790.3	P40692-1
	MLH1	ENST00000456676.7	TSL:1	c.1517T>C	p.Val506Ala	missense	Exon 13 of 17	ENSP00000416687.3	H0Y818
	MLH1	ENST00000413740.2	TSL:1	c.1517T>C	p.Val506Ala	missense	Exon 13 of 15	ENSP00000416476.2	H0Y806

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152072 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152072 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74294

African (AFR) AF: 0.00 AC: 0 AN: 41394

American (AMR) AF: 0.00 AC: 0 AN: 15266

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4820

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10610

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68000

Other (OTH) AF: 0.00 AC: 0 AN: 2092

Alfa AF: 0.00000534 Hom.: 0

Bravo AF: 0.00000378

ClinVar

ClinVar submissions

Significance: Conflicting classifications of pathogenicity

Revision: criteria provided, conflicting classifications

Pathogenic	VUS	Benign	Condition
4	1	-	not provided (5)
2	-	-	Hereditary cancer-predisposing syndrome (2)
1	-	-	Colorectal cancer, hereditary nonpolyposis, type 2 (1)
1	-	-	Hereditary nonpolyposis colon cancer (1)
1	-	-	Hereditary nonpolyposis colorectal neoplasms (1)
1	-	-	MLH1-related disorder (1)
1	-	-	not specified (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.86
BayesDel_addAF	Pathogenic	0.41	D
BayesDel_noAF	Pathogenic	0.35
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.71
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.88	D
M_CAP	Uncertain	0.095	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Uncertain	2.8	M
PhyloP100		6.2
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.7	D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		0.96	D
Vest4		0.56
MutPred		0.81		Gain of loop (P = 0.002)
MVP		0.97
MPC		0.25
ClinPred		0.98	D
GERP RS		5.9
Varity_R		0.85
gMVP		0.65
Mutation Taster		=5/95	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs63749909; hg19: chr3-37070382;