rs529845940
Variant summary
Our verdict is Uncertain significance. The variant received 0 ACMG points: 0P and 0B.
The NM_002485.5(NBN):c.940G>A(p.Val314Met) variant causes a missense change. The variant allele was found at a frequency of 0.0000403 in 1,612,628 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. V314E) has been classified as Uncertain significance.
Frequency
Consequence
NM_002485.5 missense
Scores
Clinical Significance
Conservation
Publications
- Nijmegen breakage syndromeInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Myriad Women’s Health
- rhabdomyosarcomaInheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
- idiopathic aplastic anemiaInheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
- prostate cancerInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
- hereditary breast carcinomaInheritance: AD Classification: NO_KNOWN Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 0 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152144Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000358 AC: 9AN: 251232 AF XY: 0.0000442 show subpopulations
GnomAD4 exome AF: 0.0000418 AC: 61AN: 1460366Hom.: 0 Cov.: 30 AF XY: 0.0000454 AC XY: 33AN XY: 726630 show subpopulations
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152262Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1AN XY: 74444 show subpopulations
ClinVar
Submissions by phenotype
Microcephaly, normal intelligence and immunodeficiency Uncertain:4
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This sequence change replaces valine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 314 of the NBN protein (p.Val314Met). This variant is present in population databases (rs529845940, gnomAD 0.006%). This variant has not been reported in the literature in individuals affected with NBN-related conditions. ClinVar contains an entry for this variant (Variation ID: 141727). 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 disruptive. 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. -
The NBN c.940G>A (p.Val314Met) missense change has a maximum subpopulation frequency of 0.0079% in gnomAD v2.1.1 (https://gnomad.broadinstitute.org/variant/8-90976692-C-T). Five of seven in silico tools predict a deleterious effect of this variant on protein function (PP3), but to our knowledge these predictions have not been confirmed by functional assays. To our knowledge, this variant has not been reported in individuals with Nijmegan breakage syndrome or breast cancer. In summary, this variant meets criteria to be classified as of uncertain significance based on the ACMG/AMP criteria: PP3. -
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not provided Uncertain:2
In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 24662767, 25186949, 24894818) -
The frequency of this variant in the general population, 0.000079 (9/113574 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. In a large-scale breast cancer association study, the variant was observed in an individual with breast cancer as well as in unaffected study control participants (PMID: 33471991 (2021), see also LOVD (http://databases.lovd.nl/shared/genes/NBN)). 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 benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. -
not specified Uncertain:1
Variant summary: NBN c.940G>A (p.Val314Met) alters a conserved nucleotide that results in a conservative amino acid change located in the Nibrin second BRCT domain (IPR032429) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 2.8e-05 in 245998 control chromosomes (gnomAD). This frequency is not significantly higher than expected for a pathogenic variant in NBN causing Nijmegen Breakage Syndrome (2.8e-05 vs 2.50E-03), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.940G>A in individuals affected with Nijmegen Breakage Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. A co-occurrences with the pathogenic variant MUTYH c.536A>G (p.Y179C) was found in an internal specimen. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Aplastic anemia Uncertain:1
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Hereditary cancer-predisposing syndrome Uncertain:1
The p.V314M variant (also known as c.940G>A), located in coding exon 8 of the NBN gene, results from a G to A substitution at nucleotide position 940. The valine at codon 314 is replaced by methionine, an amino acid with highly similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at