rs587779183

Positions:

• chr2-47412560-G-A
• chr2-47412560-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The ENST00000233146.7(MSH2):​c.792G>A​(p.Gln264=) variant causes a splice region, synonymous change. The variant allele was found at a frequency of 0.000000693 in 1,442,210 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MSH2 ENST00000233146.7 splice_region, synonymous
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 6.61

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MSH2	NM_000251.3	c.792G>A	p.Gln264=	splice_region_variant, synonymous_variant	4/16	ENST00000233146.7	NP_000242.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MSH2	ENST00000233146.7	c.792G>A	p.Gln264=	splice_region_variant, synonymous_variant	4/16	1	NM_000251.3	ENSP00000233146	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.93e-7 AC: 1 AN: 1442210 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 718558

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: 9.13e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary nonpolyposis colorectal neoplasms Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 21, 2019

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with MSH2-related conditions. ClinVar contains an entry for this variant (Variation ID: 237409). This variant is not present in population databases (ExAC no frequency). This sequence change affects codon 264 of the MSH2 mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the MSH2 protein. This variant also falls at the last nucleotide of exon 4 of the MSH2 coding sequence, which is part of the consensus splice site for this exon. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 30, 2022

The c.792G>A variant (also known as p.Q264Q) is located in coding exon 4 of the MSH2 gene. This variant results from a G to A substitution at nucleotide position 792. This nucleotide substitution does not change the glutamine at codon 264. However, this change occurs in the last base pair of coding exon 4, which makes it likely to have some effect on normal mRNA splicing. This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice donor site; however, direct evidence is insufficient at this time (Ambry internal data). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.33
CADD	Uncertain	24
DANN	Benign	0.90

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.98
SpliceAI score (max)		0.55		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.55		Position offset: 17

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

Publications

LitVar

Other links and lift over

dbSNP: rs587779183; hg19: chr2-47639699;