Genetic Variant MLH1:p.Ser556Thr (chr3-37040294-G-C) – ACMG Classification: Pathogenic (11 pts)

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PM1PM2PM5PP3_StrongPP5

The NM_000249.4(MLH1):c.1667G>C(p.Ser556Thr) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000311 in 1,608,450 control chromosomes in the GnomAD database, with no homozygous occurrence. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S556I) has been classified as Pathogenic.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000027 ( 0 hom. )

Consequence

MLH1
NM_000249.4 missense, splice_region

Scores

Splicing: ADA: 1.000

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:8U:1

Conservation

PhyloP100: 9.74

Publications

15 publications found

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 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

MLH1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 11 ACMG points.

PM1

In a hotspot region, there are 13 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 29 uncertain in NM_000249.4

PM2

Very rare variant in population databases, with high coverage;

PM5

Other missense variant is known to change same aminoacid residue: Variant chr3-37040294-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 89825.Status of the report is reviewed_by_expert_panel, 3 stars.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 3-37040294-G-C is Pathogenic according to our data. Variant chr3-37040294-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 185187.

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

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MLH1	NM_000249.4	MANE Select	c.1667G>C	p.Ser556Thr	missense splice_region	Exon 14 of 19	NP_000240.1	P40692-1
MLH1	NM_001354628.2		c.1667G>C	p.Ser556Thr	missense splice_region	Exon 14 of 18	NP_001341557.1	A0A087WX20
MLH1	NM_001354629.2		c.1568G>C	p.Ser523Thr	missense splice_region	Exon 13 of 18	NP_001341558.1	A0AAQ5BGZ2

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
MLH1	ENST00000231790.8	TSL:1 MANE Select	c.1667G>C	p.Ser556Thr	missense splice_region	Exon 14 of 19	ENSP00000231790.3	P40692-1
MLH1	ENST00000456676.7	TSL:1	c.1667G>C	p.Ser556Thr	missense splice_region	Exon 14 of 17	ENSP00000416687.3	H0Y818
MLH1	ENST00000413740.2	TSL:1	c.1667G>C	p.Arg556Thr	missense splice_region	Exon 14 of 15	ENSP00000416476.2	H0Y806

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152106

Hom.:

Cov.:

show subpopulations

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:

AN:

251200

AF XY:

0.00000737

show subpopulations

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:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000275

AC:

AN:

1456344

Hom.:

Cov.:

AF XY:

0.00000552

AC XY:

AN XY:

724946

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33362

American (AMR)

AF:

0.00

AC:

AN:

44704

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26084

East Asian (EAS)

AF:

0.00

AC:

AN:

39650

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86162

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53370

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.00000181

AC:

AN:

1107026

Other (OTH)

AF:

0.00

AC:

AN:

60228

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152106

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74284

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41424

American (AMR)

AF:

0.00

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5186

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10600

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68014

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.525

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00000497

Hom.:

Bravo

AF:

0.00000756

ExAC

AF:

0.00000824

AC:

ClinVar

ClinVar submissions

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

Hereditary cancer-predisposing syndrome (2)

not provided (2)

Familial cancer of breast (1)

Hereditary nonpolyposis colon cancer (1)

Hereditary nonpolyposis colorectal neoplasms (1)

Lynch syndrome (1)

Muir-Torré syndrome (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.12

BayesDel_addAF

Pathogenic

0.27

BayesDel_noAF

Pathogenic

0.16

CADD

Pathogenic

(source)

DANN

Benign

0.93

DEOGEN2

Benign

0.37

Eigen

Uncertain

0.44

Eigen_PC

Uncertain

0.36

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.29

M_CAP

Pathogenic

0.30

MetaRNN

Uncertain

0.51

MetaSVM

Benign

-0.36

PhyloP100

9.7

PROVEAN

Benign

1.5

REVEL

Uncertain

0.44

Sift

Benign

0.11

Sift4G

Pathogenic

0.0

MutPred

0.42

Loss of helix (P = 0.0123)

MVP

0.94

ClinPred

0.63

GERP RS

4.5

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Varity_R

0.64

Mutation Taster

=0/100

disease causing (ClinVar)

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.99

SpliceAI score (max)

0.92

Details are displayed if max score is > 0.2

DS_DL_spliceai

0.92

Position offset: 0

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over