rs267607949

Positions:

• chr2-47445546-A-C
• chr2-47445546-A-G
• chr2-47445546-A-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.1277-2A>C variant causes a splice acceptor change. The variant was absent in control chromosomes in GnomAD project. 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 Likely pathogenic (★★★).

• Frequency: Genomes: not found (cov: 33)
• Consequence: MSH2 NM_000251.3 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic reviewed by expert panel P:3
• Conservation: PhyloP100: 6.72

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]

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 2-47445546-A-C is Pathogenic according to our data. Variant chr2-47445546-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 90604.Status of the report is reviewed_by_expert_panel, 3 stars. Variant chr2-47445546-A-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.1277-2A>C		splice_acceptor_variant		ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.1277-2A>C		splice_acceptor_variant		1	NM_000251.3	ENSP00000233146	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 27

GnomAD4 genome Cov.: 33

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: reviewed by expert panel

Submissions by phenotype

Lynch syndrome 1 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Myriad Genetics, Inc.

Dec 11, 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. -

Lynch syndrome Pathogenic:1

Likely pathogenic, reviewed by expert panel

curation

International Society for Gastrointestinal Hereditary Tumours (InSiGHT)

Jun 21, 2019

Interrupts canonical donor splice site -

Hereditary cancer-predisposing syndrome Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

May 13, 2022

The c.1277-2A>C intronic pathogenic mutation results from an A to C substitution two nucleotides upstream from coding exon 8 in the MSH2 gene. This variant has been identified in a proband who met Amsterdam II criteria for Lynch syndrome (Cravo M et al. Gut, 2002 Mar;50:405-12; Lage PA et al. Cancer, 2004 Jul;101:172-7). Other alterations impacting the same acceptor site (c.1277-1G>A and c.1277-2A>G) have been detected in individuals meeting either Amsterdam criteria or Bethesda guidelines for hereditary non-polyposis colorectal cancer (HNPCC)/Lynch syndrome (Sheng JQ et al. Chin J Dig Dis, 2006;7:197-205; Sjursen W et al. J. Med. Genet., 2010 Sep;47:579-85). In addition, this variant has been identified in probands whose Lynch syndrome-associated tumor demonstrated high microsatellite instability and loss of MSH2 expression by immunohistochemistry (Cravo M et al. Gut, 2002 Mar;50:405-12; 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 acceptor site and will result in the creation or strengthening of a novel splice acceptor site. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Uncertain	0.10
CADD	Pathogenic	35
DANN	Benign	0.97
Eigen	Pathogenic	0.97
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
MutationTaster	Benign	1.0	D;D;D
GERP RS		4.2

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.92
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.93		Position offset: 13
DS_AL_spliceai		1.0		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs267607949; hg19: chr2-47672685;