rs117221851
Variant summary
Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2
The NM_000249.4(MLH1):c.1990-6G>A variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000173 in 1,604,360 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).
Frequency
Consequence
NM_000249.4 splice_region, intron
Scores
Clinical Significance
Conservation
Publications
- Lynch syndromeInheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: G2P, ClinGen, Orphanet
- Lynch syndrome 2Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, Genomics England PanelApp
- Muir-Torre syndromeInheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Genomics England PanelApp, Ambry Genetics, G2P, Orphanet
- mismatch repair cancer syndrome 1Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae), Orphanet, ClinGen
- Lynch syndrome 1Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae)
- ovarian cancerInheritance: AD Classification: STRONG Submitted by: Genomics England PanelApp
- malignant pancreatic neoplasmInheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- rhabdomyosarcomaInheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
- prostate cancerInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
- breast cancerInheritance: AD Classification: NO_KNOWN Submitted by: Ambry Genetics
- hereditary breast carcinomaInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Benign. The variant received -20 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000723 AC: 11AN: 152112Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000637 AC: 16AN: 250998 AF XY: 0.0000590 show subpopulations
GnomAD4 exome AF: 0.000184 AC: 267AN: 1452130Hom.: 3 Cov.: 30 AF XY: 0.000177 AC XY: 128AN XY: 723170 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000723 AC: 11AN: 152230Hom.: 0 Cov.: 32 AF XY: 0.0000806 AC XY: 6AN XY: 74424 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
Colorectal cancer, hereditary nonpolyposis, type 2 Uncertain:1Benign:2
This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -
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This variant is considered benign. This variant is intronic and is not expected to impact mRNA splicing. This variant is strongly associated with less severe personal and family histories of cancer, typical for individuals without pathogenic variants in this gene [PMID: 27363726]. -
not specified Benign:3
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Variant summary: MLH1 c.1990-6G>A alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 4/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 6.4e-05 in 250998 control chromosomes, predominantly at a frequency of 0.00076 within the East Asian subpopulation in the gnomAD database. However, the variant was reported in some East Asian subpopulations with an even higher allele frequency, e.g. in the Japanese, with an allele frequency of 0.0112 (in the jMorp database). This frequency is about 16-fold higher than the maximum expected for a pathogenic variant in MLH1 causing Hereditary Nonpolyposis Colorectal Cancer phenotype (0.00071), strongly suggesting that the variant is a benign polymorphism found primarily in populations of East Asian origin. The variant, c.1990-6G>A, has been reported in the literature in 4 Japanese individuals affected with colorectal cancer (Kiyozumi_2019), however two of the associated tumors were analyzed, and microsatellites were found to be stable and all MMR proteins were present. This report therefore does not support the association of the variant with Lynch Syndrome. Co-occurrences with other (likely) pathogenic variants have been reported (e.g. APC c.3184_3187delCAAA (p.Gln1062ValfsX63), in an internal LCA sample; MEN1 c.974C>T (p.Pro325Leu) in Shinriki_2020), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Two laboratories classified the variant as benign, three as likely benign, while one laboratory classified it as uncertain significance. Based on the evidence outlined above, the variant was classified as benign. -
Hereditary cancer-predisposing syndrome Benign:3
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This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Lynch syndrome Benign:1
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MLH1-related disorder Benign:1
This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
not provided Benign:1
This variant is associated with the following publications: (PMID: 31386297, 29338689) -
Hereditary nonpolyposis colorectal neoplasms Benign:1
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Familial cancer of breast Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at