chr22-28725036-C-T

Position:

• chr22-28725036-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The ENST00000404276.6(CHEK2):​c.533G>A​(p.Gly178Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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. G178R) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: CHEK2 ENST00000404276.6 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.03

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 4 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 4 benign, 17 uncertain in ENST00000404276.6
• 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.533G>A	p.Gly178Glu	missense_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.533G>A	p.Gly178Glu	missense_variant	4/15	1	NM_007194.4	ENSP00000385747	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1461822 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727210

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: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Malignant tumor of breast Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

Department of Pathology and Laboratory Medicine, Sinai Health System

-

The CHEK2 p.Gly178Glu variant was not identified in the literature nor was it identified in the Cosmic, MutDB, or Zhejiang University databases. The variant was identified in dbSNP (ID: rs864622691) as "With Uncertain significance allele", and in ClinVar database (classified as uncertain significance by Invitae). The variant was not identified in the following control databases: the Exome Aggregation Consortium (August 8th 2016), or the Genome Aggregation Database (Feb 27, 2017). The p.Gly178 residue is conserved in mammals but not in more distantly related organisms, and four out of five computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) suggest that the variant may impact the protein; however, this information is not predictive enough to assume pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 24, 2020

The p.G178E variant (also known as c.533G>A), located in coding exon 3 of the CHEK2 gene, results from a G to A substitution at nucleotide position 533. The glycine at codon 178 is replaced by glutamic acid, an amino acid with similar properties. This amino acid position is 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. -

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Oct 18, 2023

This sequence change replaces glycine, which is neutral and non-polar, with glutamic acid, which is acidic and polar, at codon 178 of the CHEK2 protein (p.Gly178Glu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CHEK2-related conditions. ClinVar contains an entry for this variant (Variation ID: 220904). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The glutamic acid amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.53
BayesDel_addAF	Uncertain	0.068	T
BayesDel_noAF	Benign	-0.14
CADD	Uncertain	25
DANN	Benign	0.96
DEOGEN2	Uncertain	0.59	D;.;D;D;.;D;.;.;D
Eigen	Benign	-0.0090
Eigen_PC	Benign	0.025
FATHMM_MKL	Uncertain	0.86	D
LIST_S2	Benign	0.81	.;T;.;.;T;T;.;T;T
M_CAP	Uncertain	0.16	D
MetaRNN	Uncertain	0.67	D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.67	D
MutationAssessor	Uncertain	2.1	M;M;M;M;.;M;M;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-5.2	D;D;D;D;D;.;D;D;.
REVEL	Uncertain	0.54
Sift	Uncertain	0.018	D;D;D;D;D;.;D;D;.
Sift4G	Uncertain	0.048	D;T;D;D;T;.;T;T;T
Polyphen		0.59	P;B;P;P;P;P;B;.;.
Vest4		0.47
MutPred		0.70		Gain of solvent accessibility (P = 0.012);Gain of solvent accessibility (P = 0.012);Gain of solvent accessibility (P = 0.012);Gain of solvent accessibility (P = 0.012);.;Gain of solvent accessibility (P = 0.012);Gain of solvent accessibility (P = 0.012);.;Gain of solvent accessibility (P = 0.012);
MVP		0.96
MPC		0.059
ClinPred		0.98	D
GERP RS		3.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.84
gMVP		0.59

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: rs864622691; hg19: chr22-29121024; COSMIC: COSV105899903; COSMIC: COSV105899903;