8-89937034-A-T
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Variant summary
Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2
The NM_002485.5(NBN):c.2226T>A(p.Asp742Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,610,586 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★).
Frequency
Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000021 ( 0 hom. )
Consequence
NBN
NM_002485.5 missense
NM_002485.5 missense
Scores
3
5
11
Clinical Significance
Conservation
PhyloP100: 0.269
Genes affected
NBN (HGNC:7652): (nibrin) Mutations in this gene are associated with Nijmegen breakage syndrome, an autosomal recessive chromosomal instability syndrome characterized by microcephaly, growth retardation, immunodeficiency, and cancer predisposition. The encoded protein is a member of the MRE11/RAD50 double-strand break repair complex which consists of 5 proteins. This gene product is thought to be involved in DNA double-strand break repair and DNA damage-induced checkpoint activation. [provided by RefSeq, Jul 2008]
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ACMG classification
Classification made for transcript
Verdict is Uncertain_significance. Variant got 2 ACMG points.
PM2
Very rare variant in population databases, with high coverage;
Transcripts
RefSeq
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | MANE | Protein | UniProt |
---|---|---|---|---|---|---|---|---|
NBN | NM_002485.5 | c.2226T>A | p.Asp742Glu | missense_variant | 15/16 | ENST00000265433.8 | NP_002476.2 |
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | #exon/exons | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
NBN | ENST00000265433.8 | c.2226T>A | p.Asp742Glu | missense_variant | 15/16 | 1 | NM_002485.5 | ENSP00000265433.4 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152204Hom.: 0 Cov.: 32
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GnomAD3 exomes AF: 0.0000160 AC: 4AN: 249956Hom.: 0 AF XY: 0.0000222 AC XY: 3AN XY: 135112
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GnomAD4 exome AF: 0.00000206 AC: 3AN: 1458382Hom.: 0 Cov.: 29 AF XY: 0.00000276 AC XY: 2AN XY: 725728
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GnomAD4 genome AF: 0.0000131 AC: 2AN: 152204Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1AN XY: 74364
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ClinVar
Significance: Uncertain significance
Submissions summary: Uncertain:7
Revision: criteria provided, multiple submitters, no conflicts
LINK: link
Submissions by phenotype
Microcephaly, normal intelligence and immunodeficiency Uncertain:3
Uncertain significance, no assertion criteria provided | clinical testing | Natera, Inc. | May 04, 2021 | - - |
Uncertain significance, criteria provided, single submitter | clinical testing | Labcorp Genetics (formerly Invitae), Labcorp | Aug 24, 2022 | This sequence change replaces aspartic acid, which is acidic and polar, with glutamic acid, which is acidic and polar, at codon 742 of the NBN protein (p.Asp742Glu). This variant is present in population databases (rs767523514, gnomAD 0.02%). 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: 230832). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0". The glutamic acid amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. - |
Uncertain significance, criteria provided, single submitter | clinical testing | Genome-Nilou Lab | Nov 07, 2021 | - - |
not specified Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Women's Health and Genetics/Laboratory Corporation of America, LabCorp | May 19, 2021 | Variant summary: NBN c.2226T>A (p.Asp742Glu) results in a conservative amino acid change located in the DNA repair Nbs1, C-terminal domain (IPR013908) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 1.6e-05 in 249956 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. To our knowledge, no occurrence of c.2226T>A in individuals affected with Nijmegen Breakage Syndrome and no experimental evidence demonstrating its impact on protein function have been reported. Two ClinVar submitters (evaluation after 2014) have cited the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. - |
Aplastic anemia Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Baylor Genetics | Nov 02, 2023 | - - |
not provided Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Quest Diagnostics Nichols Institute San Juan Capistrano | Aug 26, 2024 | The NBN c.2226T>A (p.Asp742Glu) variant has been reported in the published literature in a cohort of individuals with unspecified cancer (PMID: 36346689 (2023)). The frequency of this variant in the general population, 0.00016 (4/24682 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 benign or damaging. Based on the available information, we are unable to determine the clinical significance of this variant. - |
Hereditary cancer-predisposing syndrome Uncertain:1
Uncertain significance, criteria provided, single submitter | clinical testing | Ambry Genetics | Mar 31, 2024 | The p.D742E variant (also known as c.2226T>A), located in coding exon 15 of the NBN gene, results from a T to A substitution at nucleotide position 2226. The aspartic acid at codon 742 is replaced by glutamic acid, 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 tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. - |
Computational scores
Source:
Name
Calibrated prediction
Score
Prediction
AlphaMissense
Pathogenic
BayesDel_addAF
Benign
T
BayesDel_noAF
Benign
CADD
Benign
DANN
Uncertain
DEOGEN2
Benign
T;T;.
Eigen
Benign
Eigen_PC
Benign
FATHMM_MKL
Benign
D
LIST_S2
Benign
T;T;T
M_CAP
Benign
D
MetaRNN
Uncertain
T;T;T
MetaSVM
Benign
T
MutationAssessor
Uncertain
M;.;.
PrimateAI
Uncertain
T
PROVEAN
Benign
N;N;.
REVEL
Uncertain
Sift
Pathogenic
D;D;.
Sift4G
Pathogenic
D;D;D
Polyphen
D;.;.
Vest4
MutPred
Gain of loop (P = 0);.;.;
MVP
MPC
ClinPred
D
GERP RS
Varity_R
gMVP
Splicing
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SpliceAI score (max)
Details are displayed if max score is > 0.2
Find out detailed SpliceAI scores and Pangolin per-transcript scores at