3-37025629-TA-TAAA

Variant names:

• chr3-37025629-T-TAA
• rs1553650466
• NM_000249.4:c.1039-7_1039-6dupAA

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP6

The NM_000249.4(MLH1):​c.1039-7_1039-6dupAA variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 19)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: MLH1 NM_000249.4 splice_region, intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• Conservation: PhyloP100: 0.0980
• Publications: 0 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: Likely_benign. The variant received -1 ACMG points.

• BP6: Variant 3-37025629-T-TAA is Benign according to our data. Variant chr3-37025629-T-TAA is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 2053422.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MLH1	NM_000249.4	c.1039-7_1039-6dupAA		splice_region_variant, intron_variant	Intron 11 of 18	ENST00000231790.8	NP_000240.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MLH1	ENST00000231790.8	c.1039-8_1039-7insAA		splice_region_variant, intron_variant	Intron 11 of 18	1	NM_000249.4	ENSP00000231790.3

Frequencies

GnomAD3 genomes Cov.: 19

GnomAD4 exome AF: 0.00000997 AC: 11 AN: 1103212 Hom.: 0 Cov.: 20 AF XY: 0.00000734 AC XY: 4 AN XY: 545228

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

African (AFR) AF: 0.0000947 AC: 2 AN: 21110

American (AMR) AF: 0.00 AC: 0 AN: 17426

Ashkenazi Jewish (ASJ) AF: 0.0000569 AC: 1 AN: 17588

East Asian (EAS) AF: 0.00 AC: 0 AN: 29082

South Asian (SAS) AF: 0.00 AC: 0 AN: 38368

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 36848

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 3212

European-Non Finnish (NFE) AF: 0.00000893 AC: 8 AN: 895804

Other (OTH) AF: 0.00 AC: 0 AN: 43774

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 19

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:1

Aug 23, 2024

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MLH1 c.1039-7_1039-6dup variant has not been reported in individuals with MLH1-related conditions in the published literature. It also has not been reported in large, multi-ethnic general populations (Genome Aggregation Database, http://gnomad.broadinstitute.org). Analysis of this variant using software algorithms for the prediction of the effect of nucleotide changes on splicing yielded predictions that this variant may affect proper MLH1 mRNA splicing. Based on the available information, we are unable to determine the clinical significance of this variant. -

Muir-Torré syndrome Uncertain:1

May 13, 2022

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Hereditary nonpolyposis colorectal neoplasms Benign:1

Jan 14, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.098

Splicing

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

Other links and lift over

dbSNP: rs1553650466; hg19: chr3-37067120;