rs1553351554

Positions:

• chr2-47412413-GATA-G

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM1 PM2 PM4_Supporting PP3_Moderate

The NM_000251.3(MSH2):​c.648_650del​(p.Ile217del) variant causes a inframe deletion, splice region change. 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 Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MSH2 NM_000251.3 inframe_deletion, splice_region
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 5.99

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 7 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 6 benign, 15 uncertain in NM_000251.3
• PM2: Very rare variant in population databases, with high coverage
• PM4: Nonframeshift variant in NON repetitive region in NM_000251.3. Strenght limited to Supporting due to length of the change: 1aa.
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MSH2	NM_000251.3	c.648_650del	p.Ile217del	inframe_deletion, splice_region_variant	4/16	ENST00000233146.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MSH2	ENST00000233146.7	c.648_650del	p.Ile217del	inframe_deletion, splice_region_variant	4/16	1	NM_000251.3	P1

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: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Aug 26, 2022	This variant causes a deletion of one amino acid in the MSH2 protein. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a family in the Colon Cancer Family Registry (PMID: 28944238). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	May 06, 2022	The c.648_650delAAT variant (also known as p.I217del) is located in coding exon 4 of the MSH2 gene. This variant results from an in-frame AAT deletion at nucleotide positions 648 to 650. This results in the deletion of an isoleucine at codon 217. This variant has been identified in a proband(s) whose Lynch syndrome-associated tumor demonstrated loss of MSH2/MSH6 expression by immunohistochemistry (Ambry internal data). This amino acid position is highly conserved through mammals but not in all available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis (Choi Y et al., PLoS ONE 2012; 7(10):e46688). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Carcinoma of colon Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The MSH2 p.Ile217del variant was identified in 1 of 2462 proband chromosomes (frequency: 0.0004) from individuals or families with colorectal cancer and was not identified in 186 control chromosomes from healthy individuals (DeRycke 2017). The variant was also identified in ClinVar (classified as uncertain significance by Color). The variant was not identified in dbSNP, COGR, Cosmic, UMD-LSDB, Zhejiang University Database, Mismatch Repair Genes Variant Database, or Insight Hereditary Tumors databases. The variant was not identified in the following control databases: the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). This variant is an in-frame deletion resulting in the removal of an isoleucine (Ile) residue at codon 217; the impact of this alteration on MSH2 protein function is not known. The variant occurs outside of the splicing consensus sequence and 1 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict a greater than 10% difference in splicing; this is not very predictive of pathogenicity. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

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		1.0		Position offset: 4
DS_AL_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: rs1553351554; hg19: chr2-47639552;