22-28725251-T-C

Position:

• chr22-28725251-T-C

Variant summary

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

The NM_007194.4(CHEK2):​c.436A>G​(p.Ile146Val) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: CHEK2 NM_007194.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.47

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 domain FHA (size 62) in uniprot entity CHK2_HUMAN there are 10 pathogenic changes around while only 2 benign (83%) in NM_007194.4
• 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.436A>G	p.Ile146Val	missense_variant	3/15	ENST00000404276.6	NP_009125.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
CHEK2	ENST00000404276.6	c.436A>G	p.Ile146Val	missense_variant	3/15	1	NM_007194.4	ENSP00000385747	P2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial cancer of breast Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Apr 05, 2022

This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 146 of the CHEK2 protein (p.Ile146Val). 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: 946163). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Benign"; Align-GVGD: "Class C25"). 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

May 10, 2024

The p.I146V variant (also known as c.436A>G), located in coding exon 2 of the CHEK2 gene, results from an A to G substitution at nucleotide position 436. The isoleucine at codon 146 is replaced by valine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Uncertain	24
DANN	Uncertain	0.98
DEOGEN2	Benign	0.37	T;.;T;T;.;T;.;.;.;T;.;.
Eigen	Uncertain	0.28
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.94	.;D;.;.;D;D;.;D;D;D;D;D
M_CAP	Benign	0.085	D
MetaRNN	Uncertain	0.69	D;D;D;D;D;D;D;D;D;D;D;D
MetaSVM	Uncertain	0.73	D
MutationAssessor	Uncertain	2.4	M;M;M;M;.;M;M;.;.;.;.;.
MutationTaster	Benign	1.0	D;D;D;D;D;D;D;D;D;D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Benign	-0.87	N;N;N;N;N;.;N;N;N;.;.;.
REVEL	Uncertain	0.63
Sift	Benign	0.040	D;D;D;D;D;.;D;D;D;.;.;.
Sift4G	Uncertain	0.029	D;D;D;D;D;.;D;D;T;D;.;.
Polyphen		0.68	P;P;P;P;P;P;P;.;.;.;.;.
Vest4		0.59
MutPred		0.66		Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);.;Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);.;Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);Loss of methylation at K142 (P = 0.1168);
MVP		0.94
MPC		0.047
ClinPred		0.77	D
GERP RS		4.8
Varity_R		0.52
gMVP		0.36

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: rs781678896; hg19: chr22-29121239;