7-5982890-G-T

Position:

• chr7-5982890-G-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000535.7(PMS2):​c.2108C>A​(p.Thr703Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000689 in 1,451,658 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T703M) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: PMS2 NM_000535.7 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 10.0

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 Likely_pathogenic. Variant got 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 16 uncertain in NM_000535.7
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.877

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PMS2	NM_000535.7	c.2108C>A	p.Thr703Lys	missense_variant	12/15	ENST00000265849.12

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PMS2	ENST00000265849.12	c.2108C>A	p.Thr703Lys	missense_variant	12/15	1	NM_000535.7	P3

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.89e-7 AC: 1 AN: 1451658 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 721822

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: 9.04e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Sep 19, 2016

This variant is denoted PMS2 c.2108C>A at the cDNA level, p.Thr703Lys (T703K) at the protein level, and results in the change of a Threonine to a Lysine (ACG>AAG). This variant has not, to our knowledge, been published in the literature as pathogenic or benign. PMS2 Thr703Lys was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, suggesting it is not a common benign variant in these populations. Since Threonine and Lysine differ in some properties, this is considered a semi-conservative amino acid substitution. PMS2 Thr703Lys occurs at a position that is not conserved and is located within the nuclease domain (Guarne 2001). In silico analyses predict that this variant is probably damaging to protein structure and function. Based on currently available evidence, it is unclear whether PMS2 Thr703Lys is a pathogenic or benign variant. We consider it to be a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 19, 2016

The p.T703K variant (also known as c.2108C>A), located in coding exon 12 of the PMS2 gene, results from a C to A substitution at nucleotide position 2108. The threonine at codon 703 is replaced by lysine, an amino acid with similar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6475 samples (12950 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.001% (greater than 150000 alleles tested) in our clinical cohort. This amino acid position is not well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. 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
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Benign	0.37	T;.;.;.;.;.
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.42
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D;.;D;.;D
M_CAP	Uncertain	0.13	D
MetaRNN	Pathogenic	0.88	D;D;D;D;D;D
MetaSVM	Uncertain	0.33	D
MutationAssessor	Uncertain	2.5	M;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;N
PrimateAI	Uncertain	0.55	T
PROVEAN	Uncertain	-3.5	D;D;.;.;.;D
REVEL	Pathogenic	0.65
Sift	Uncertain	0.014	D;D;.;.;.;D
Sift4G	Uncertain	0.0060	D;D;.;.;.;D
Polyphen		0.94	P;D;.;.;D;P
Vest4		0.73
MutPred		0.71		Gain of ubiquitination at T703 (P = 0.017);.;.;.;.;.;
MVP		0.87
MPC		3.5
ClinPred		0.98	D
GERP RS		4.7
Varity_R		0.91
gMVP		0.78

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Publications

LitVar

Other links and lift over

dbSNP: rs370196722; hg19: chr7-6022521;