7-5999277-T-C

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PVS1_Moderate PM2 PP3_Strong PP5_Very_Strong

The NM_000535.7(PMS2):c.538-2A>G variant causes a splice acceptor change. The variant allele was found at a frequency of 0.00000205 in 1,460,788 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 Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: PMS2 NM_000535.7 splice_acceptor
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:12
• Conservation: PhyloP100: 6.24

Genes affected

PMS2 (HGNC:9122): (PMS1 homolog 2, mismatch repair system component) The protein encoded by this gene is a key component of the mismatch repair system that functions to correct DNA mismatches and small insertions and deletions that can occur during DNA replication and homologous recombination. This protein forms heterodimers with the gene product of the mutL homolog 1 (MLH1) gene to form the MutL-alpha heterodimer. The MutL-alpha heterodimer possesses an endonucleolytic activity that is activated following recognition of mismatches and insertion/deletion loops by the MutS-alpha and MutS-beta heterodimers, and is necessary for removal of the mismatched DNA. There is a DQHA(X)2E(X)4E motif found at the C-terminus of the protein encoded by this gene that forms part of the active site of the nuclease. Mutations in this gene have been associated with hereditary nonpolyposis colorectal cancer (HNPCC; also known as Lynch syndrome) and Turcot syndrome. [provided by RefSeq, Apr 2016]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PVS1: Splicing variant, NOT destroyed by nmd, known LOF gene, truncates exone, which is 0.06450367 fraction of the gene. Cryptic splice site detected, with MaxEntScore 5.8, offset of 49, new splice context is: tgcatactgtatcatttcAGcag. Cryptic site results in frameshift 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 7-5999277-T-C is Pathogenic according to our data. Variant chr7-5999277-T-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 411028.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PMS2	NM_000535.7	c.538-2A>G		splice_acceptor_variant		ENST00000265849.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PMS2	ENST00000265849.12	c.538-2A>G		splice_acceptor_variant		1	NM_000535.7	P3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000119 AC: 3 AN: 251470 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135916

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000867

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1460788 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 726788

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:12

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Lynch syndrome Pathogenic:3

Likely pathogenic, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Jul 19, 2023	This variant causes an A to G nucleotide substitution at the -2 position of intron 5 of the PMS2 gene. Splice site prediction tools suggest that this variant may have a significant impact on RNA splicing. Although this prediction has not been confirmed in published RNA studies, this variant is expected to abolish the acceptor site at exon 6 and result in an absent or disrupted protein product. This variant has been reported in individuals affected with Lynch syndrome (PMID: 28640387, 31101557, 31992580). This variant has been identified in 3/251470 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Loss of PMS2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Apr 10, 2020	Variant summary: PMS2 c.538-2A>G 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. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 3 acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 1.2e-05 in 251470 control chromosomes (gnomAD). c.538-2A>G has been reported in the literature in individuals affected with Lynch syndrome and colorectal cancer (Sunga_2017, Ricker_2017, Mork_2019). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Five ClinVar submitters (evaluation after 2014) cite the variant as pathogenic (2x) and likely pathogenic (3x). Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Dec 27, 2017	The c.538-2A>G variant in PMS2 has been reported in at least 1 Hispanic individu al with PMS2-associated cancer and absence of PMS2 staining via IHC in their tum or sample (Sunga 2017, Ricker 2017). It has also been identified in 3/33582 of L atino chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broa dinstitute.org/; dbSNP rs758304323). This frequency is low enough to be consiste nt with the frequency of Lynch syndrome in the general population. This variant occurs in the invariant region (+/- 1,2) of the splice consensus sequence and is predicted to cause altered splicing leading to an abnormal or absent protein. A nother variant (c.538-3C>G) impacting the same splice region was shown to result in two aberrant RNA transcripts (in-frame skipping of exon 6 and a 49-bp deleti on producing a frameshift) in an affected carrier (Borras 2013). Furthermore, a large deletion resulting in the in-frame loss of exon 6 was classified as pathog enic on September 5, 2013 by the ClinGen-approved InSiGHT expert panel (ClinVar SCV000108368.2). In summary, although additional studies are required to fully e stablish its clinical significance, the c.538-2A>G variant is likely pathogenic. ACMG/AMP Criteria applied: PM4, PM5, PP3, PP4. -

Hereditary cancer-predisposing syndrome Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Feb 27, 2024	The c.538-2A>G intronic pathogenic mutation results from an A to G substitution two nucleotides upstream from coding exon 6 in the PMS2 gene. This mutation has been identified in a proband who met Amsterdam II criteria for Lynch syndrome and tumor demonstrated loss of PMS2 expression by immunohistochemistry (IHC) (Ambry internal data). This alteration was also detected in a proband with colorectal cancer diagnosed at age 28, whose tumor demonstrated high microsatellite instability with non-interpretable PMS2 expression by IHC (Wang Q et al. J Med Genet, 2020 07;57:487-499). Another alteration impacting the same acceptor site (c.538-1G>C) has been reported in a child with constitutional mismatch repair deficiency syndrome in conjunction with a PMS2 gross deletion (Bakry D et al. Eur J Cancer. 2014 Mar;50(5):987-96). Alterations that disrupt the canonical splice site are expected to result in aberrant splicing. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). The resulting transcript is predicted to be in-frame and is not expected to trigger nonsense-mediated mRNA decay. The exact functional effect of the missing amino acids is unknown; however, the impacted region is critical for protein function (Ambry internal data). Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Likely pathogenic, criteria provided, single submitter	curation	Sema4, Sema4	Feb 17, 2022	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	May 31, 2023	This variant causes an A to G nucleotide substitution at the -2 position of intron 5 of the PMS2 gene. Splice site prediction tools suggest that this variant may have a significant impact on RNA splicing. Although this prediction has not been confirmed in published RNA studies, this variant is expected to abolish the acceptor site at exon 6 and result in an absent or disrupted protein product. This variant has been reported in individuals affected with Lynch syndrome (PMID: 28640387, 31101557, 31992580). This variant has been identified in 3/251470 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Loss of PMS2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Lynch syndrome 4 Pathogenic:3

Pathogenic, criteria provided, single submitter	clinical testing	Counsyl	May 17, 2018	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Baylor Genetics	Oct 18, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Myriad Genetics, Inc.	Apr 03, 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. -

Gastric cancer Pathogenic:1

Pathogenic, no assertion criteria provided

research

Laboratory for Genotyping Development, RIKEN

Jul 01, 2021

- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 24, 2022

Canonical splice site variant predicted to result in aberrant splicing leading to in-frame loss of the adjacent exon 6, which would disrupt the ATPase domain (Guarne 2001); Observed in individuals with Lynch-associated cancers and tumor studies consistent with pathogenic variants in this gene (Ricker 2017, Mork 2019, Wang 2020); This variant is associated with the following publications: (PMID: 28640387, 28449805, 31101557, 31992580, 29922827, 27535533, 11574484) -

Hereditary nonpolyposis colorectal neoplasms Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jan 09, 2024

This sequence change affects an acceptor splice site in intron 5 of the PMS2 gene. RNA analysis indicates that disruption of this splice site induces altered splicing and may result in an absent or disrupted protein product. This variant is present in population databases (rs758304323, gnomAD 0.009%). Disruption of this splice site has been observed in individual(s) with clinical features of Lynch syndrome and/or constitutional mismatch repair deficiency syndrome (PMID: 24440087, 28449805, 28640387, 31101557, 31992580; Invitae). In at least one individual the data is consistent with being in trans (on the opposite chromosome) from a pathogenic variant. ClinVar contains an entry for this variant (Variation ID: 411028). Studies have shown that disruption of this splice site results in partial deletion of exon 6 and introduces a premature termination codon (Invitae). The resulting mRNA is expected to undergo nonsense-mediated decay. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Pathogenic	0.32
Cadd	Pathogenic	31
Dann	Uncertain	0.99
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	1.0	D
MutationTaster	Benign	1.0	D;D;D;D;D
GERP RS		5.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.67		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.67		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: rs758304323; hg19: chr7-6038908; COSMIC: COSV56220281; COSMIC: COSV56220281;