22-28703567-C-T

Variant names:

• chr22-28703567-C-T
• rs878854926
• NM_007194.4:c.847-1G>A

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_007194.4(CHEK2):​c.847-1G>A variant causes a splice acceptor, intron change. The variant allele was found at a frequency of 0.000000712 in 1,403,684 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: 31)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: CHEK2 NM_007194.4 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 5.47
• Publications: 1 publications found

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]

CHEK2 Gene-Disease associations (from GenCC):

• CHEK2-related cancer predisposition

  Inheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics
• hereditary breast carcinoma

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
• Li-Fraumeni syndrome 2

  Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
• acute myeloid leukemia

  Inheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
• hereditary nonpolyposis colon cancer

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• familial ovarian cancer

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 5.5, offset of 37, new splice context is: taaaaacttttttgatgcAGaag. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 22-28703567-C-T is Pathogenic according to our data. Variant chr22-28703567-C-T is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 240758.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHEK2	NM_007194.4	c.847-1G>A		splice_acceptor_variant, intron_variant	Intron 7 of 14	ENST00000404276.6	NP_009125.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHEK2	ENST00000404276.6	c.847-1G>A		splice_acceptor_variant, intron_variant	Intron 7 of 14	1	NM_007194.4	ENSP00000385747.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 7.12e-7 AC: 1 AN: 1403684 Hom.: 0 Cov.: 25 AF XY: 0.00000143 AC XY: 1 AN XY: 699182

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 32380

American (AMR) AF: 0.00 AC: 0 AN: 41750

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25422

East Asian (EAS) AF: 0.00 AC: 0 AN: 39310

South Asian (SAS) AF: 0.00 AC: 0 AN: 83082

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52304

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5690

European-Non Finnish (NFE) AF: 9.39e-7 AC: 1 AN: 1065302

Other (OTH) AF: 0.00 AC: 0 AN: 58444

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Pathogenic:2

Aug 09, 2022

Color Diagnostics, LLC DBA Color Health

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant causes a G to A nucleotide substitution at the canonical -1 position of intron 7 splice acceptor site of the CHEK2 gene. Splice site prediction tools predict that this variant may have a significant impact on RNA splicing. Although functional RNA studies have not been reported for this variant, it is expected to disrupt CHEK2 protein function. This variant has not been reported in individuals affected with hereditary cancer in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). A different variant impacting a canonical position c.847-2A>G in intron 7 splice acceptor site is reported to be disease-causing (ClinVar variation ID: 822474). Loss of CHEK2 function is a known mechanism of disease (clinicalgenome.org). Based on the available evidence, this variant is classified as Likely Pathogenic. -

Jul 26, 2024

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.847-1G>A intronic variant results from a G to A substitution one nucleotide upstream from coding exon 7 of the CHEK2 gene. This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice acceptor site. Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -

Familial cancer of breast Pathogenic:2

Jun 27, 2023

Myriad Genetics, Inc.

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Dec 20, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change affects an acceptor splice site in intron 7 of the CHEK2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in CHEK2 are known to be pathogenic (PMID: 21876083, 24713400). This variant is not present in population databases (gnomAD no frequency). Disruption of this splice site has been observed in individual(s) with breast cancer (PMID: 32427313). ClinVar contains an entry for this variant (Variation ID: 240758). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -

Breast carcinoma Pathogenic:1

Aug 21, 2021

Medical Genetics Laboratory, Umraniye Training and Research Hospital, University of Health Sciences

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

Invasive Breast Carcinoma EST= + PRO = + HER2 = + KI = 30% -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.43	D
BayesDel_noAF	Pathogenic	0.37
CADD	Pathogenic	31
DANN	Uncertain	1.0
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	0.96
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		5.5
GERP RS		5.4
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.94
SpliceAI score (max)		0.88		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.88		Position offset: -1

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

Other links and lift over

dbSNP: rs878854926; hg19: chr22-29099555;