22-28725290-T-C

Variant names:

• chr22-28725290-T-C
• rs1060502703
• NM_007194.4:c.397A>G

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 4P and 2B. PM1 PM2 BP4_Moderate

The NM_007194.4(CHEK2):​c.397A>G​(p.Thr133Ala) 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 benign 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. T133R) has been classified 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:5
• Conservation: PhyloP100: 3.35
• Publications: 3 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: Uncertain_significance. The variant received 2 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 54 uncertain in NM_007194.4
• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.2518201).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CHEK2	NM_007194.4	c.397A>G	p.Thr133Ala	missense_variant	Exon 3 of 15	ENST00000404276.6	NP_009125.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CHEK2	ENST00000404276.6	c.397A>G	p.Thr133Ala	missense_variant	Exon 3 of 15	1	NM_007194.4	ENSP00000385747.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial cancer of breast Uncertain:4

Oct 31, 2023

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 08, 2023

Myriad Genetics, Inc.

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is classified as a variant of uncertain significance as there is insufficient evidence to determine its impact on protein function and/or cancer risk. -

Aug 17, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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: 410035). 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 threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 133 of the CHEK2 protein (p.Thr133Ala). -

Feb 16, 2018

Counsyl

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

This submission and the accompanying classification are no longer maintained by the submitter. For more information on current observations and classification, please contact variantquestions@myriad.com. -

Hereditary cancer-predisposing syndrome Uncertain:1

Aug 11, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T133A variant (also known as c.397A>G), located in coding exon 2 of the CHEK2 gene, results from an A to G substitution at nucleotide position 397. The threonine at codon 133 is replaced by alanine, an amino acid with similar properties. This alteration was detected in an individual with melanoma (Stolarova L et al. Biomedicines, 2020 Oct;8). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Benign	22
DANN	Uncertain	0.98
DEOGEN2	Benign	0.41	T;.;T;T;.;T;.;.;.;T;.;.
Eigen	Benign	-0.083
Eigen_PC	Benign	0.044
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Benign	0.85	.;T;.;.;T;T;.;T;T;T;T;T
M_CAP	Benign	0.063	D
MetaRNN	Benign	0.25	T;T;T;T;T;T;T;T;T;T;T;T
MetaSVM	Uncertain	-0.0039	T
MutationAssessor	Benign	1.1	L;L;L;L;.;L;L;.;.;.;.;.
PhyloP100		3.4
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-1.2	N;N;N;N;N;.;N;N;N;.;.;.
REVEL	Uncertain	0.58
Sift	Benign	0.15	T;T;T;T;T;.;T;T;T;.;.;.
Sift4G	Benign	0.16	T;T;T;T;T;.;T;T;D;D;.;.
Polyphen		0.056	B;P;B;B;B;B;P;.;.;.;.;.
Vest4		0.59
MutPred		0.37		Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);.;Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);.;Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);Loss of phosphorylation at T133 (P = 0.0223);
MVP		0.96
MPC		0.032
ClinPred		0.50	D
GERP RS		4.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.37
gMVP		0.44
Mutation Taster		=69/31	polymorphism

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

Other links and lift over

dbSNP: rs1060502703; hg19: chr22-29121278;