rs267607950

Positions:

• chr2-47429942-G-A
• chr2-47429942-G-C
• chr2-47429942-G-T

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000251.3(MSH2):​c.1276+1G>A variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,166 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MSH2 NM_000251.3 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic reviewed by expert panel P:14 O:1
• Conservation: PhyloP100: 9.05

Genes affected

MSH2 (HGNC:7325): (mutS homolog 2) This locus is frequently mutated in hereditary nonpolyposis colon cancer (HNPCC). When cloned, it was discovered to be a human homolog of the E. coli mismatch repair gene mutS, consistent with the characteristic alterations in microsatellite sequences (RER+ phenotype) found in HNPCC. Two transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]

MSH2 (HGNC:):

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47429942-G-A is Pathogenic according to our data. Variant chr2-47429942-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 90590.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47429942-G-A is described in Lovd as [Pathogenic]. Variant chr2-47429942-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.1276+1G>A		splice_donor_variant, intron_variant		ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.1276+1G>A		splice_donor_variant, intron_variant		1	NM_000251.3	ENSP00000233146.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461166 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726918

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:14 Other:1

Revision: reviewed by expert panel

Submissions by phenotype

not provided Pathogenic:4 Other:1

Pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Jul 01, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Institute for Clinical Genetics, University Hospital TU Dresden, University Hospital TU Dresden	Jul 01, 2022	PVS1, PM1, PM2_SUP -
not provided, no classification provided	in vitro	MutSpliceDB: a database of splice sites variants effects on splicing, NIH	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Nov 21, 2022	- -
Pathogenic, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Dec 16, 2022	This variant disrupts a canonical splice-donor site and interferes with normal MSH2 mRNA splicing. It has not been reported in large, multi-ethnic general populations (http://gnomad.broadinstitute.org). In the published literature, the variant has been reported in individuals with hereditary non-polyposis colorectal cancer (HNPCC) (PMID: 19669161 (2010), 15849733 (2005)). This variant has been shown to result in aberrant MSH2 splicing (PMID: 36113988 (2022), 19669161 (2010)). Based on the available information, this variant is classified as pathogenic. -

Lynch syndrome 1 Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Aug 01, 2023	This variant is considered likely pathogenic. This variant occurs within a consensus splice junction and is predicted to result in abnormal mRNA splicing of either an out-of-frame exon or an in-frame exon necessary for protein stability and/or normal function. -
Pathogenic, criteria provided, single submitter	clinical testing	Genetics and Molecular Pathology, SA Pathology	Jun 22, 2021	- -

Lynch syndrome Pathogenic:2

Pathogenic, reviewed by expert panel	research	International Society for Gastrointestinal Hereditary Tumours (InSiGHT)	Sep 05, 2013	Multifactorial likelihood analysis posterior probability >0.99 -
Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Oct 27, 2021	The c.1276+1G>A variant in MSH2 has been reported in at least 2 individuals with Lynch syndrome (Mangold 2005 PMID: 15849733, Betz 2010 PMID: 19669161) and in other clinical laboratories in ClinVar (Variation ID: 90590). It was absent from large population studies. This variant occurs within the canonical splice site (+/- 1,2) and is predicted to cause altered splicing leading to an abnormal or absent protein. In vitro functional studies corroborate this prediction, where PCR on patient RNA has shown to cause aberrant splicing, causes the activation of a cryptic splice site in exon 7 resulting in the in-frame deletion of 16 amino acids in the hMSH3/hMSH6 interaction domain ich is required for proper MSH2 protein function (Betz 2010 PMID: 19669161). In summary, this variant meets criteria to be classified as likely pathogenic for autosomal dominant Lynch syndrome. ACMG/AMP Criteria applied: PS4_Supporting, PM2_Supporting, PP3, PVS1_Strong, PM4. -

Hereditary cancer-predisposing syndrome Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Mar 29, 2022	This variant causes a G to A nucleotide substitution at the +1 position of intron 7 of the MSH2 gene. RNA studies have shown that this variant causes use of a cryptic site in exon 7 resulting in an in-frame deletion of sixteen amino acids in the MSH6/MSH3 interaction domain. This variant has been reported in individuals affected with Lynch syndrome (PMID: 15849733, 16216036, 19669161). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MSH2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	May 08, 2024	The c.1276+1G>A intronic pathogenic mutation results from a G to A substitution one nucleotide after coding exon 7 of the MSH2 gene. This mutation has been identified in multiple Lynch syndrome families and shown to cause abnormal splicing (Mangold E et al, Int. J. Cancer 2005 Sep; 116(5):692-702; Betz B et al, J. Cancer Res. Clin. Oncol. 2010 Jan; 136(1):123-34). This mutation has also been identified in at least one proband who met Amsterdam I/II criteria for Lynch syndrome and tumor demonstrated loss of MSH2/MSH6 expression by immunohistochemistry (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In silico splice site analysis predicts that this alteration will weaken the native splice donor site and may result in the creation or strengthening of a novel splice donor site; however, direct evidence is insufficient at this time (Ambry internal data). In addition to the clinical data presented in the literature, alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as a disease-causing mutation. -

Carcinoma of colon Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The c.1276+1G>A variant was identified in 2 of 908 proband chromosomes (frequency: 0.02) from individuals or families with Lynch syndrome (Mangold 2005). The variant was also identified in dbSNP (ID: rs267607950) “With pathogenic, probable-pathogenic allele”, HGMD, “Mismatch Repair Genes Variant Database”, “InSiGHT Colon Cancer Database”, “Zhejiang Colon Cancer Database”, and the “MMR Gene Unclassified Variants Database”. The c.1276+1G>A variant is predicted to cause abnormal splicing because the nucleotide substitution occurs in the invariant region of the splice consensus sequence. In addition, in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing in all five programs. In a functional study, RT-PCR analysis of the variant allele found that the variant activated a cryptic 5’ splice site in exon 7, resulting in a deletion of 48 nucleotides from this exon, and ultimately an in-frame deletion of 16 amino acids of the hMSH3/hMSH6 interaction domain of the MSH2 protein (Betz 2010). In summary, based on the above information, this variant meets our laboratory’s criteria to be classified as pathogenic. -

Hereditary nonpolyposis colon cancer Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Nov 25, 2022

Variant summary: MSH2 c.1276+1G>A is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. At least two publications report experimental evidence that this variant affects mRNA splicing (Betz_2010, Petersen_2013). The variant was absent in 251052 control chromosomes. c.1276+1G>A has been reported in the literature in multiple individuals affected with Hereditary Nonpolyposis Colorectal Cancer (e.g. Betz_2010, Mangold_2005, Maliaka_1996, Petersen_2013, Kim_2022). These data indicate that the variant is very likely to be associated with disease. Five ClinVar submitters (evaluation after 2014) have classified the variant as pathogenic, and one ClinVar submitter classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Lynch-like syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

clinical testing

Constitutional Genetics Lab, Leon Berard Cancer Center

Jul 01, 2019

- -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 28, 2023

For these reasons, this variant has been classified as Pathogenic. Studies have shown that disruption of this splice site results in the activation of a cryptic splice site in exon 7 (PMID: 19669161). ClinVar contains an entry for this variant (Variation ID: 90590). Disruption of this splice site has been observed in individuals with Lynch syndrome (PMID: 15849733, 19669161, 21520333). It has also been observed to segregate with disease in related individuals. This variant is not present in population databases (gnomAD no frequency). This sequence change affects a donor splice site in intron 7 of the MSH2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in the loss of 16 amino acid residue(s), but is expected to preserve the integrity of the reading-frame. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.30
CADD	Pathogenic	35
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.98
FATHMM_MKL	Uncertain	0.96	D
GERP RS		5.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.44		Position offset: -49
DS_DL_spliceai		1.0		Position offset: -1

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

Publications

LitVar

Other links and lift over

dbSNP: rs267607950; hg19: chr2-47657081;