3-37012077-A-T

Variant names:

• chr3-37012077-A-T
• rs1799977
• NM_000249.4:c.655A>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.655A>T​(p.Ile219Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,796 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I219V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MLH1 NM_000249.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.05
• Publications: 254 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: G2P, ClinGen, Orphanet
• 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: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, 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

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

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 5 benign, 36 uncertain in NM_000249.4
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.828

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

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH1	NM_000249.4	MANE Select	c.655A>T	p.Ile219Phe	missense	Exon 8 of 19	NP_000240.1
	MLH1	NM_001354628.2		c.655A>T	p.Ile219Phe	missense	Exon 8 of 18	NP_001341557.1
	MLH1	NM_001354629.2		c.556A>T	p.Ile186Phe	missense	Exon 7 of 18	NP_001341558.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MLH1	ENST00000231790.8	TSL:1 MANE Select	c.655A>T	p.Ile219Phe	missense	Exon 8 of 19	ENSP00000231790.3
	MLH1	ENST00000456676.7	TSL:1	c.655A>T	p.Ile219Phe	missense	Exon 8 of 17	ENSP00000416687.3
	MLH1	ENST00000413740.2	TSL:1	c.655A>T	p.Ile219Phe	missense	Exon 8 of 15	ENSP00000416476.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460796 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726800

African (AFR) AF: 0.00 AC: 0 AN: 33460

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.00 AC: 0 AN: 39690

South Asian (SAS) AF: 0.00 AC: 0 AN: 86242

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

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

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111032

Other (OTH) AF: 0.00 AC: 0 AN: 60352

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 30277

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.34
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.16
CADD	Uncertain	24
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.82	D
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.83	D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Pathogenic	3.1	M
PhyloP100		2.0
PrimateAI	Uncertain	0.51	T
PROVEAN	Uncertain	-3.3	D
REVEL	Pathogenic	0.82
Sift	Uncertain	0.0030	D
Sift4G	Uncertain	0.0060	D
Polyphen		0.98	D
Vest4		0.79
MutPred		0.51		Loss of stability (P = 0.1595)
MVP		0.91
MPC		0.48
ClinPred		0.99	D
GERP RS		4.6
Varity_R		0.65
gMVP		0.84
Mutation Taster		=34/66	disease causing

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: rs1799977; hg19: chr3-37053568;