NM_000251.3:c.646-1_648delGATA

Variant names:

• chr2-47412409-AATAG-A
• rs1553351549
• NM_000251.3:c.646-1_648delGATA

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PVS1_Moderate PM2 PP5_Moderate

The NM_000251.3(MSH2):​c.646-1_648delGATA​(p.Ile216_Ile217del) variant causes a splice acceptor, conservative inframe deletion, splice region, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MSH2 NM_000251.3 splice_acceptor, conservative_inframe_deletion, splice_region, intron
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 9.62

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 Likely_pathogenic. Variant got 6 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.052406415 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.5, offset of -24, new splice context is: tattccttttctcatagtAGttt. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-47412409-AATAG-A is Pathogenic according to our data. Variant chr2-47412409-AATAG-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 433877.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MSH2	NM_000251.3	c.646-1_648delGATA	p.Ile216_Ile217del	splice_acceptor_variant, conservative_inframe_deletion, splice_region_variant, intron_variant	Exon 4 of 16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.646-4_646-1delATAG		splice_acceptor_variant, splice_region_variant, intron_variant	Intron 3 of 15	1	NM_000251.3	ENSP00000233146.2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Carcinoma of colon Pathogenic:1

-

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The MSH2 c.646-1_648del variant was not identified in the literature nor was it identified in in dbSNP, NHLBI GO Exome Sequencing Project, the Exome Aggregation Consortium, Clinvitae, COSMIC, Mismatch Repair Genes Variant Database, MMR Gene Unclassified Variants Database, InSiGHT Colon Cancer Gene Variant Database (LOVD), Zhejiang Colon Cancer Database (LOVD), ClinVar database, GeneInsight - COGR database and UMD database. The c.646-1_648del variant is predicted to cause abnormal splicing because the nucleotide substitution occurs in the invariant region of the splice consensus sequence. In addition, 5 of 5 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer, HumanSpliceFinder) predict a greater than 10% difference in splicing. This alteration is then predicted to result in a truncated or absent protein and loss of function. Loss of function variants of the MSH2 gene are an established mechanism of disease in Lynch syndrome and this is the type of variant expected to cause the disorder. In summary, based on the above information, this variant meets our laboratory’s criteria to be classified as pathogenic. -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Jan 09, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (gnomAD no frequency). This variant has been observed in individual(s) with clinical features of Lynch syndrome (Invitae). ClinVar contains an entry for this variant (Variation ID: 433877). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant results in the deletion of part of exon 4 (c.646-1_648del) of the MSH2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in MSH2 are known to be pathogenic (PMID: 15849733, 24362816). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.88		Position offset: -22
DS_AL_spliceai		1.0		Position offset: 5

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553351549; hg19: chr2-47639548;