NM_002485.5:c.1979G>C

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_002485.5(NBN):c.1979G>C(p.Arg660Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000151 in 1,591,830 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R660K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000083 ( 0 hom. )

Consequence

NBN
NM_002485.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9B:1

Conservation

PhyloP100: 2.62

Publications

1 publications found

Variant links:

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]

NBN Gene-Disease associations (from GenCC):

Nijmegen breakage syndrome
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Myriad Women’s Health
rhabdomyosarcoma
Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
idiopathic aplastic anemia
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
prostate cancer
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
hereditary breast carcinoma
Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

NBN links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.20809087).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBN	NM_002485.5 link	c.1979G>C	p.Arg660Thr	missense_variant	Exon 13 of 16	ENST00000265433.8	NP_002476.2	O60934

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8 link	c.1979G>C	p.Arg660Thr	missense_variant	Exon 13 of 16	1	NM_002485.5	ENSP00000265433.4		O60934

Frequencies

GnomAD3 genomes

AF:

0.0000789

AC:

AN:

152110

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000265

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000319

AC:

AN:

251164

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.000369

Gnomad AMR exome

AF:

0.0000578

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.00000834

AC:

AN:

1439604

Hom.:

Cov.:

AF XY:

0.00000697

AC XY:

AN XY:

717420

show subpopulations

African (AFR)

AF:

0.000242

AC:

AN:

32992

American (AMR)

AF:

0.0000448

AC:

AN:

44668

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25988

East Asian (EAS)

AF:

0.00

AC:

AN:

39396

South Asian (SAS)

AF:

0.00

AC:

AN:

85708

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53322

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5710

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1092142

Other (OTH)

AF:

0.0000335

AC:

AN:

59678

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.504

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000788

AC:

AN:

152226

Hom.:

Cov.:

AF XY:

0.0000537

AC XY:

AN XY:

74424

show subpopulations

African (AFR)

AF:

0.000265

AC:

AN:

41564

American (AMR)

AF:

0.0000654

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10592

Middle Eastern (MID)

AF:

0.00

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67978

Other (OTH)

AF:

0.00

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.00

Hom.:

Bravo

AF:

0.0000491

ExAC

AF:

0.0000247

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:9Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency

Uncertain:3

Jan 27, 2020

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Nov 07, 2021

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Apr 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine, which is basic and polar, with threonine, which is neutral and polar, at codon 660 of the NBN protein (p.Arg660Thr). This variant is present in population databases (rs201781110, gnomAD 0.03%). 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: 216567). 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. -

not provided

Uncertain:2

May 15, 2023

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The frequency of this variant in the general population, 0.00032 (8/24962 chromosomes, http://gnomad.broadinstitute.org), is uninformative in assessment of its pathogenicity. In the published literature, the variant was found both in individuals with breast cancer as well as unaffected individuals in a large breast cancer association study (PMID: 33471991 (2021), see also LOVD (https://databases.lovd.nl/shared/variants/NBN)). 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. -

Aug 06, 2024

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

In silico analysis indicates that this missense variant does not alter protein structure/function; Observed in cases and controls in a breast cancer study (PMID: 33471991); This variant is associated with the following publications: (PMID: 36346689, 24894818, 33471991) -

Hereditary cancer-predisposing syndrome

Uncertain:1Benign:1

Nov 01, 2022

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Jul 01, 2021

Sema4, Sema4

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:curation

- -

not specified

Uncertain:1

Jun 23, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: NBN c.1979G>C (p.Arg660Thr) results in a non-conservative amino acid change in 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 3.5e-05 in 282548 control chromosomes (gnomAD). This frequency is not higher than expected for a pathogenic variant in NBN causing Nijmegen Breakage Syndrome (3.5e-05 vs 0.0025), allowing no conclusion about variant significance. In a large study evaluating breast cancer cases and controls in the Breast Cancer Association Consortium (BCAC), the variant was reported in 1/60466 cases, but was also found in 1/53461 controls (Dorling_2021 through LOVD). This report does not provide unequivocal conclusions about association of the variant with Nijmegen Breakage Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication have been ascertained in the context of this evaluation (PMID: 33471991). Eight submitters have cited clinical-significance assessments (VUS: 7; Likely benign: 1) for this variant to ClinVar after 2014. Based on the evidence outlined above, the variant was classified as uncertain significance. -

Aplastic anemia

Uncertain:1

Mar 02, 2024

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

NBN-related disorder

Uncertain:1

Oct 20, 2022

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The NBN c.1979G>C variant is predicted to result in the amino acid substitution p.Arg660Thr. To our knowledge, this variant has not been reported in the literature in individuals with NBN-related disorders. This variant has been observed in 1/60466 cases in a large study evaluating breast cancer (Breast Cancer Association Consortium. et al 2021. PubMed ID: 33471991; https://databases.lovd.nl/shared/variants/0000753532#00014315). This variant is reported in 0.032% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/8-90958459-C-G) and is interpreted as uncertain significance (https://preview.ncbi.nlm.nih.gov/clinvar/variation/216567/). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.33

BayesDel_addAF

Benign

-0.23

BayesDel_noAF

Benign

-0.25

CADD

Benign

(source)

DANN

Benign

0.97

DEOGEN2

Benign

0.40

T;T

Eigen

Benign

-0.15

Eigen_PC

Benign

0.0049

FATHMM_MKL

Uncertain

0.85

LIST_S2

Uncertain

0.88

D;D

M_CAP

Benign

0.057

MetaRNN

Benign

0.21

T;T

MetaSVM

Benign

-0.85

MutationAssessor

Uncertain

2.1

M;.

PhyloP100

2.6

PrimateAI

Benign

0.38

PROVEAN

Benign

-2.1

N;N

REVEL

Benign

0.22

Sift

Uncertain

0.015

D;D

Sift4G

Uncertain

0.011

D;D

Polyphen

0.22

B;.

Vest4

0.60

MVP

0.71

MPC

0.24

ClinPred

0.13

GERP RS

4.8

Varity_R

0.31

gMVP

0.50

Mutation Taster

=88/12

polymorphism

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over