3-37008866-C-T

Variant names:

• chr3-37008866-C-T
• rs63750834
• NM_000249.4:c.506C>T

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP3

The NM_000249.4(MLH1):​c.506C>T​(p.Pro169Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,613,910 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P169Q) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 31)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:6
• Conservation: PhyloP100: 4.26
• Publications: 4 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, G2P, Orphanet
• Lynch syndrome 2

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

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

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

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 40 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.782

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.506C>T	p.Pro169Leu	missense	Exon 6 of 19	NP_000240.1
	MLH1	NM_001354628.2		c.506C>T	p.Pro169Leu	missense	Exon 6 of 18	NP_001341557.1
	MLH1	NM_001354629.2		c.407C>T	p.Pro136Leu	missense	Exon 5 of 18	NP_001341558.1

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH1	ENST00000231790.8	TSL:1 MANE Select	c.506C>T	p.Pro169Leu	missense	Exon 6 of 19	ENSP00000231790.3
	MLH1	ENST00000456676.7	TSL:1	c.506C>T	p.Pro169Leu	missense	Exon 6 of 17	ENSP00000416687.3
	MLH1	ENST00000413740.2	TSL:1	c.506C>T	p.Pro169Leu	missense	Exon 6 of 15	ENSP00000416476.2

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152070 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: 0.00

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

GnomAD2 exomes AF: 0.00000398 AC: 1 AN: 251430 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000879

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461840 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727224

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111976

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0136242), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152070 Hom.: 0 Cov.: 31 AF XY: 0.0000135 AC XY: 1 AN XY: 74280

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41414

American (AMR) AF: 0.00 AC: 0 AN: 15252

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 5198

South Asian (SAS) AF: 0.00 AC: 0 AN: 4826

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10574

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

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68018

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

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.0000198 Hom.: 0

Bravo AF: 0.00000378

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

ClinVar submissions as Germline

Significance: Uncertain significance

Revision: criteria provided, multiple submitters, no conflicts

Pathogenic	VUS	Benign	Condition
-	2	-	Hereditary cancer-predisposing syndrome (2)
-	1	-	Colorectal cancer, hereditary nonpolyposis, type 2 (1)
-	1	-	Hereditary nonpolyposis colorectal neoplasms (1)
-	1	-	Lynch syndrome (1)
-	1	-	not provided (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.75	D
Eigen	Uncertain	0.56
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Benign	0.023	T
MetaRNN	Pathogenic	0.78	D
MetaSVM	Benign	-0.45	T
MutationAssessor	Uncertain	2.3	M
PhyloP100		4.3
PrimateAI	Uncertain	0.79	T
PROVEAN	Pathogenic	-5.4	D
REVEL	Uncertain	0.59
Sift	Uncertain	0.0020	D
Sift4G	Uncertain	0.022	D
Polyphen		0.38	B
Vest4		0.64
MVP		0.93
MPC		0.083
ClinPred		0.98	D
GERP RS		6.2
Varity_R		0.59
gMVP		0.82
Mutation Taster		=16/84	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.21		Position offset: 39

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

Other links and lift over

dbSNP: rs63750834; hg19: chr3-37050357;