22-28694066-G-T

Variant names:

• chr22-28694066-G-T
• rs142763740
• NM_007194.4:c.1427C>A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM2 PM5 PP3_Strong

The NM_007194.4(CHEK2):​c.1427C>A​(p.Thr476Lys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. T476M) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHEK2 NM_007194.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:6
• Conservation: PhyloP100: 3.15

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 Likely_pathogenic. Variant got 8 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr22-28694066-G-A is described in Lovd as [Pathogenic].
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.95

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHEK2	NM_007194.4	c.1427C>A	p.Thr476Lys	missense_variant	Exon 13 of 15	ENST00000404276.6	NP_009125.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHEK2	ENST00000404276.6	c.1427C>A	p.Thr476Lys	missense_variant	Exon 13 of 15	1	NM_007194.4	ENSP00000385747.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Apr 20, 2023	This missense variant replaces threonine with lysine at codon 476 of the CHEK2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Functional studies demonstrated this variant had intermediate activity in a yeast DNA damage response assay (PMID: 22419737) but similar kinase activity to wild-type (PMID: 16835864). This variant has been observed in a prostate tumor sample (PMID: 16835864) and an individual referred for genetic testing (PMID: 31159747). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneKor MSA	Aug 01, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 14, 2023	The p.T476K variant (also known as c.1427C>A), located in coding exon 12 of the CHEK2 gene, results from a C to A substitution at nucleotide position 1427. The threonine at codon 476 is replaced by lysine, an amino acid with similar properties. This alteration has been reported in 1/1197 individuals from Greece, Romania, and Turkey undergoing evaluation for inherited cancer predisposition (Tsaousis GN et al. BMC Cancer, 2019 Jun;19:535). A yeast based complementation assay demonstrated that this alteration produced intermediate growth compared to wild-type and negative controls (Roeb, Higgens, and King. Hum. Mol. Genet. 2012 Jun; 21(12):2738-44). In addition, functional assays of CHEK2 kinase activity demonstrated that this alteration results in partially reduced activity (Wu X et al. Hum. Mutat. 2006 Aug; 27(8):742-7). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	May 19, 2021	- -

Familial cancer of breast Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 12, 2024	This sequence change replaces threonine, which is neutral and polar, with lysine, which is basic and polar, at codon 476 of the CHEK2 protein (p.Thr476Lys). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with prostate cancer (PMID: 16835864). ClinVar contains an entry for this variant (Variation ID: 486833). 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. Experimental studies have shown that this missense change affects CHEK2 function (PMID: 16835864, 22419737). 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Baylor Genetics	Mar 16, 2024	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.22
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Benign	0.31	T;.;T;.;T;.;T;.;.
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.57
FATHMM_MKL	Uncertain	0.84	D
LIST_S2	Uncertain	0.88	.;D;.;D;.;D;D;D;.
M_CAP	Benign	0.016	T
MetaRNN	Pathogenic	0.95	D;D;D;D;D;D;D;D;D
MetaSVM	Benign	-0.47	T
MutationAssessor	Uncertain	2.2	M;.;M;.;M;.;M;.;.
PrimateAI	Uncertain	0.52	T
PROVEAN	Pathogenic	-4.5	D;D;D;.;D;D;.;D;D
REVEL	Uncertain	0.45
Sift	Uncertain	0.0020	D;D;D;.;D;D;.;D;D
Sift4G	Uncertain	0.0040	D;D;D;.;D;D;.;D;D
Polyphen		1.0	D;D;D;.;D;D;D;D;D
Vest4		0.56
MutPred		0.87		Gain of ubiquitination at T476 (P = 0.0247);.;Gain of ubiquitination at T476 (P = 0.0247);.;Gain of ubiquitination at T476 (P = 0.0247);.;Gain of ubiquitination at T476 (P = 0.0247);.;.;
MVP		0.76
MPC		0.035
ClinPred		0.98	D
GERP RS		4.4
Varity_R		0.86
gMVP		0.77

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs142763740; hg19: chr22-29090054;