rs1555926708

Positions:

• chr22-28724977-C-G
• chr22-28724977-C-T

Variant summary

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

The NM_007194.4(CHEK2):​c.592G>C​(p.Val198Leu) variant causes a missense, splice region change. The variant was absent in control chromosomes in GnomAD project. 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 Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHEK2 NM_007194.4 missense, splice_region
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:3
• Conservation: PhyloP100: 5.65

Genes affected

CHEK2 (HGNC:16627): (checkpoint kinase 2) In response to DNA damage and replication blocks, cell cycle progression is halted through the control of critical cell cycle regulators. The protein encoded by this gene is a cell cycle checkpoint regulator and putative tumor suppressor. It contains a forkhead-associated protein interaction domain essential for activation in response to DNA damage and is rapidly phosphorylated in response to replication blocks and DNA damage. When activated, the encoded protein is known to inhibit CDC25C phosphatase, preventing entry into mitosis, and has been shown to stabilize the tumor suppressor protein p53, leading to cell cycle arrest in G1. In addition, this protein interacts with and phosphorylates BRCA1, allowing BRCA1 to restore survival after DNA damage. Mutations in this gene have been linked with Li-Fraumeni syndrome, a highly penetrant familial cancer phenotype usually associated with inherited mutations in TP53. Also, mutations in this gene are thought to confer a predisposition to sarcomas, breast cancer, and brain tumors. This nuclear protein is a member of the CDS1 subfamily of serine/threonine protein kinases. Several 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
CHEK2	NM_007194.4	c.592G>C	p.Val198Leu	missense_variant, splice_region_variant	4/15	ENST00000404276.6	NP_009125.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHEK2	ENST00000404276.6	c.592G>C	p.Val198Leu	missense_variant, splice_region_variant	4/15	1	NM_007194.4	ENSP00000385747.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000468 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:1 Uncertain:1

Pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Sep 24, 2021	The c.592G>C variant (also known as p.V198L), located in coding exon 3 of the CHEK2 gene, results from a G to C substitution at nucleotide position 592. The amino acid change results in valine to leucine at codon 198, an amino acid with highly similar properties. However, this change occurs in the last base pair of coding exon 3, which makes it likely to have some effect on normal mRNA splicing. In silico splice site analysis predicts that this alteration will weaken the native splice donor site and RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). Another alteration impacting the same donor site (c.592+1G>A) has been shown to have a similar impact on splicing (Ambry internal data). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -
Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Dec 29, 2021	- -

CHEK2-related disorder Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 04, 2023

The CHEK2 c.592G>C variant is predicted to result in the amino acid substitution p.Val198Leu. This variant is located at the last nucleotide of the exon and is predicted to abolish the canonical splice donor site (SpliceAI, Jaganathan et al. 2019. PubMed ID: 30661751). To our knowledge, this variant has not been reported in the literature or in a large population database (http://gnomad.broadinstitute.org), indicating this variant is rare. In ClinVar, this variant has conflicting interpretations of uncertain and pathogenic (https://www.ncbi.nlm.nih.gov/clinvar/variation/481730/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 16, 2023

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. Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown this missense change is associated with multiple alternative transcripts involving intronic insertion, but one or more of the resulting mRNA isoform(s) may be naturally occurring (Invitae). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant  is likely to be tolerated. ClinVar contains an entry for this variant (Variation ID: 481730). This variant has not been reported in the literature in individuals affected with CHEK2-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 198 of the CHEK2 protein (p.Val198Leu). This variant also falls at the last nucleotide of exon 4, which is part of the consensus splice site for this exon. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Benign	-0.20	T
BayesDel_noAF	Uncertain	-0.080
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Benign	0.013	T
Eigen	Uncertain	0.44
Eigen_PC	Uncertain	0.47
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.32	T
M_CAP	Benign	0.059	D
MetaRNN	Benign	0.22	T
Sift4G	Benign	0.36	T
Vest4		0.14
MVP		0.33
ClinPred		0.76	D
GERP RS		5.9

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.99
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.99		Position offset: 0

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

Publications

LitVar

Other links and lift over

dbSNP: rs1555926708; hg19: chr22-29120965; COSMIC: COSV60420741; COSMIC: COSV60420741;