chr22-28725251-T-G
Variant summary
Our verdict is Uncertain significance. The variant received 3 ACMG points: 4P and 1B. PM1PM2BP4
The NM_007194.4(CHEK2):c.436A>C(p.Ile146Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00000248 in 1,613,938 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. I146V) has been classified as Uncertain significance.
Frequency
Consequence
NM_007194.4 missense
Scores
Clinical Significance
Conservation
Publications
- CHEK2-related cancer predispositionInheritance: AD Classification: DEFINITIVE Submitted by: Ambry Genetics
- hereditary breast carcinomaInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), ClinGen
- Li-Fraumeni syndrome 2Inheritance: AD Classification: DEFINITIVE Submitted by: G2P
- acute myeloid leukemiaInheritance: AD Classification: MODERATE Submitted by: Genomics England PanelApp
- hereditary nonpolyposis colon cancerInheritance: AD Classification: LIMITED Submitted by: ClinGen
- familial ovarian cancerInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 3 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| CHEK2 | NM_007194.4 | c.436A>C | p.Ile146Leu | 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.436A>C | p.Ile146Leu | missense_variant | Exon 3 of 15 | 1 | NM_007194.4 | ENSP00000385747.1 |
Frequencies
GnomAD3 genomes AF: 0.00000657 AC: 1AN: 152118Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000119 AC: 3AN: 251306 AF XY: 0.0000221 show subpopulations
GnomAD4 exome AF: 0.00000205 AC: 3AN: 1461820Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3AN XY: 727210 show subpopulations
GnomAD4 genome AF: 0.00000657 AC: 1AN: 152118Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74308 show subpopulations
ClinVar
Submissions by phenotype
Hereditary cancer-predisposing syndrome Uncertain:3
This missense variant replaces isoleucine with leucine at codon 146 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). To our knowledge, functional studies have not been reported for this variant. In a large breast cancer case-control study conducted by the BRIDGES consortium, this variant was reported in 2/60466 cases and 3/53461 unaffected controls (PMID: 33471991; Leiden Open Variation Database DB-ID CHEK2_000226). This variant has been identified in 3/251306 chromosomes 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.
The p.I146L variant (also known as c.436A>C), located in coding exon 2 of the CHEK2 gene, results from an A to C substitution at nucleotide position 436. The isoleucine at codon 146 is replaced by leucine, an amino acid with highly similar properties. This variant was reported as functional in a study assessing CHEK2-complementation through quantification of KAP1 phosphorylation and CHK2 autophosphorylation in human RPE1-CHEK2-knockout cells (Stolarova L et al. Clin Cancer Res, 2023 Aug;29:3037-3050). 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.
PM1, PM2_Supporting c.436A>C, located in exon 3 of the CHEK2 gene, is predicted to result in the substitution of Ile by Leu at codon 146, p.(Ile146Leu). This variant affects a highly conserved amino acid of the FHA-domain (115-175 aa) (PM1). This variant is found in 3/268178 alleles at a frequency of 0.0011% in the gnomAD v2.1.1 database, non-cancer dataset (PM2_Supporting). The SpliceAI algorithm predicts no significant impact on splicing and the REVEL meta-predictor score (0,403) for this variant is indeterminate regarding the effect that it may have on protein function according Pejaver 2022 thresholds (PMID: 36413997). To our knowledge, no relevant clinical data have been reported for this variant. A recent CHEK2-complementation assay quantifying KAP1 phosphorylation and CHK2 autophosphorylation in human RPE1–CHEK2-knockout cells has shown that this missense change does not affect CHEK2 function (PMID: 37449874). There are no reports of pathogenic missense variants in the same codon. This variant has been reported in individuals undergoing hereditary cancer panel testing (PMID: 32906215), as well as in breast cancer cases and control individuals in a large scale breast cancer association study (PMID: 33471991). This variant has been reported in ClinVar (7x uncertain significance) and LOVD (1x uncertain significance) databases. Based on currently available information, the variant c.436A>C should be considered an uncertain significance variant.
not provided Uncertain:2
In the published literature, this variant has been reported in individuals undergoing hereditary cancer panel testing (PMID: 32906215 (2020)), as well as in breast cancer cases and control individuals in a large scale breast cancer association study (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared/genes/CHEK2)). The frequency of this variant in the general population, 0.000026 (3/113604 chromosomes (Genome Aggregation Database, http://gnomad.broadinstitute.org)), is uninformative in the assessment of its pathogenicity. Analysis of this variant using bioinformatics tools for the prediction of the effect of amino acid changes on protein structure and function yielded conflicting predictions that this variant is deleterious or benign. Based on the available information, we are unable to determine the clinical significance of this variant.
Observed in a cohort of individuals with suspected hereditary cancer (PMID: 32906215); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 22419737, 19782031, 32906215)
Familial cancer of breast Uncertain:2
This sequence change replaces isoleucine, which is neutral and non-polar, with leucine, which is neutral and non-polar, at codon 146 of the CHEK2 protein (p.Ile146Leu). This variant is present in population databases (rs781678896, gnomAD 0.003%). 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: 479549). 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. 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.
Familial cancer of breast;C0376358:Prostate cancer;C0585442:Bone osteosarcoma;C5882668:CHEK2-related cancer predisposition Uncertain:1
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at