rs199749372
Variant summary
Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate
The NM_007194.4(CHEK2):c.661A>G(p.Ile221Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000113 in 1,591,400 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_007194.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Likely_benign. Variant got -2 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000197 AC: 3AN: 152172Hom.: 0 Cov.: 32
GnomAD3 exomes AF: 0.0000131 AC: 3AN: 229264Hom.: 0 AF XY: 0.00 AC XY: 0AN XY: 123858
GnomAD4 exome AF: 0.0000104 AC: 15AN: 1439110Hom.: 0 Cov.: 27 AF XY: 0.0000126 AC XY: 9AN XY: 715084
GnomAD4 genome AF: 0.0000197 AC: 3AN: 152290Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74484
ClinVar
Submissions by phenotype
not provided Uncertain:3Benign:1
The CHEK2 c.661A>G (p.Ile221Val) variant has been reported in the published literature in individuals with breast cancer (PMIDs: 33471991 (2021), 31206626 (2019), 28779002 (2017)), colorectal cancer (PMIDs: 28944238 (2017), 27978560 (2016)), and in reportedly healthy individuals (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared)). Experimental studies indicate this variant has neutral to partial effect on CHEK2 protein function (PMIDs: 37449874 (2023), 30851065 (2019)). The frequency of this variant in the general population, 0.000026 (3/117518 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 predictions that this variant is benign. Based on the available information, we are unable to determine the clinical significance of this variant. -
CHEK2: BP1, BP4, BS3:Supporting -
The CHEK2 c.661A>G; p.Ile221Val variant (rs199749372), to our knowledge, is not reported in the medical literature but is reported by multiple laboratories in ClinVar (Variation ID: 140835). This variant is found in the general population with an overall allele frequency of 0.003% (1/30956 alleles) in the Genome Aggregation Database. The isoleucine at codon 221 is moderately conserved but computational analyses (SIFT, PolyPhen-2) predict that this variant is tolerated. However, given the lack of clinical and functional data, the significance of the p.Ile221Val variant is uncertain at this time. -
Published functional study demonstrates no damaging effect: normal cell growth after MMS-induced DNA damage (Delimitsou et al., 2019); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Also known as c.790A>G, p.Ile264Val; This variant is associated with the following publications: (PMID: 27978560, 31398194, 31241222, 31106920, 30851065, 19782031, 22419737, 29769011) -
Hereditary cancer-predisposing syndrome Uncertain:2
This missense variant replaces isoleucine with valine at codon 221 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 have shown this variant to have a neutral effect on CHEK2 DNA damage repair activity in a yeast complementation assay (PMID: 30851065), and intermediate impact on KAP1 phosphorylation and neutral impact CHEK2 autophosphorylation in a mammalian cell complementation assay (PMID: 37449874). This variant has been reported in an individual affected with colorectal cancer (PMID: 27978560). In a large breast cancer case-control meta-analysis, this variant was reported in 4/73048 cases and 2/88658 unaffected controls (PMID: 37449874). This variant has been identified in 4/260646 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.I221V variant (also known as c.661A>G), located in coding exon 4 of the CHEK2 gene, results from an A to G substitution at nucleotide position 661. The isoleucine at codon 221 is replaced by valine, an amino acid with highly similar properties. This alteration behaved as functional in an in vivo, yeast-based growth rate assay (Delimitsou A et al. Hum Mutat, 2019 05;40:631-648). In another functional study assessing CHEK2-complementation in human RPE1-CHEK2-knockout cells, this alteration was reported as functional through quantification of CHK2 autophosphorylation but intermediate in KAP1 phosphorylation (Stolarova L et al. Clin Cancer Res, 2023 Aug;29:3037-3050). This variant has been reported in cohorts of individuals with early onset colon cancer (Pearlman R et al. JAMA Oncol, 2017 Apr;3:464-471; DeRycke MS et al. Mol Genet Genomic Med, 2017 Sep;5:553-569), African American males with prostate cancer (Matejcic M et al. JCO Precis Oncol, 2020 Jan;4:32-43), and breast cancer cases and controls (Decker B et al. J Med Genet, 2017 11;54:732-741, Weitzel JN et al. Cancer, 2019 Aug;125:2829-2836; Dorling L et al. N Engl J Med, 2021 Feb4;384(5):428-39). This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Familial cancer of breast Uncertain:2
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This sequence change replaces isoleucine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 221 of the CHEK2 protein (p.Ile221Val). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individual(s) with breast cancer, colorectal cancer, and/or prostate cancer (PMID: 27978560, 28779002, 28944238, 31206626, 32832836). ClinVar contains an entry for this variant (Variation ID: 140835). 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 are conflicting or provide insufficient evidence to determine the effect of this variant on CHEK2 function (PMID: 30851065, 37449874). 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. -
CHEK2-related disorder Uncertain:1
The CHEK2 c.661A>G variant is predicted to result in the amino acid substitution p.Ile221Val. This variant has been reported in an individual with colorectal cancer and in a breast cancer cohort study (eTable 2, Pearlman et al. 2017. PubMed ID: 27978560; Table S5, Decker et al. 2017. PubMed ID: 28779002). Experimental studies using a yeast-based assay suggest this variant is benign (Table 1, Delimitsou et al. 2019. PubMed ID: 30851065). This variant is reported in 0.0031% of alleles in individuals of Latino descent in gnomAD (http://gnomad.broadinstitute.org/variant/22-29115405-T-C). It is interpreted as uncertain significance in ClinVar (https://preview.ncbi.nlm.nih.gov/clinvar/variation/140835/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at