NM_002485.5:c.1317A>G

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS1

The NM_002485.5(NBN):c.1317A>G(p.Ile439Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000191 in 1,613,870 control chromosomes in the GnomAD database, including 1 homozygotes. 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. I439V) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0010 ( 1 hom., cov: 32)

Exomes 𝑓: 0.00010 ( 0 hom. )

Consequence

NBN
NM_002485.5 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:9

Conservation

PhyloP100: 0.0150

Publications

5 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: Benign. The variant received -9 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.004268855).

BP6

Variant 8-89955363-T-C is Benign according to our data. Variant chr8-89955363-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 127858.

BS1

Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00103 (157/152274) while in subpopulation AFR AF = 0.00359 (149/41560). AF 95% confidence interval is 0.00312. There are 1 homozygotes in GnomAd4. There are 59 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBN	NM_002485.5 link	c.1317A>G	p.Ile439Met	missense_variant	Exon 10 of 16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8 link	c.1317A>G	p.Ile439Met	missense_variant	Exon 10 of 16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes

AF:

0.00103

AC:

156

AN:

152156

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00357

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000393

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:

0.000955

GnomAD2 exomes

AF:

0.000271

AC:

AN:

251276

AF XY:

0.000133

show subpopulations

Gnomad AFR exome

AF:

0.00412

Gnomad AMR exome

AF:

0.0000289

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:

0.000103

AC:

151

AN:

1461596

Hom.:

Cov.:

AF XY:

0.0000811

AC XY:

AN XY:

727108

show subpopulations

African (AFR)

AF:

0.00406

AC:

136

AN:

33466

American (AMR)

AF:

0.000112

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26120

East Asian (EAS)

AF:

0.00

AC:

AN:

39688

South Asian (SAS)

AF:

0.00

AC:

AN:

86246

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

8.99e-7

AC:

AN:

1111806

Other (OTH)

AF:

0.000149

AC:

AN:

60386

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.497

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:

0.00103

AC:

157

AN:

152274

Hom.:

Cov.:

AF XY:

0.000792

AC XY:

AN XY:

74462

show subpopulations

African (AFR)

AF:

0.00359

AC:

149

AN:

41560

American (AMR)

AF:

0.000392

AC:

AN:

15288

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5190

South Asian (SAS)

AF:

0.00

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10624

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67996

Other (OTH)

AF:

0.000945

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.485

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Genome Hom

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:

0.000414

Hom.:

Bravo

AF:

0.00114

ESP6500AA

AF:

0.00567

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000387

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:9

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency

Uncertain:1Benign:2

Nov 07, 2021

Genome-Nilou Lab

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 13, 2018

Illumina Laboratory Services, Illumina

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

not specified

Benign:3

Jun 21, 2022

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

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: NBN c.1317A>G (p.Ile439Met) results in a conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00027 in 251276 control chromosomes, predominantly at a frequency of 0.0041 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 1.64 fold of the estimated maximal expected allele frequency for a pathogenic variant in NBN causing Nijmegen Breakage Syndrome phenotype (0.0025), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. In addition, the variant was reported in 23/2559 African American women including 1 homozygote (i.e. with a frequency of 0.009), who were older than 70 years of age, and never had cancer (FLOSSIES database). These data strongly suggest that the variant is a benign polymorphism found primarily in populations of African origin. c.1317A>G has been reported in the literature as a VUS in settings of multigene panel testing among individuals affected with various tumor phenotypes (example, Yurgelun 2015, Ring 2016, Haiman 2013) including one homozygous germline occurrence in a colorectal cancer patient who was diagnosed over the age of 50 (Hampel 2018). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Eight clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with a predominant consensus as benign/likely benign (n=6); (VUS, n=2). Based on the evidence outlined above, the variant was classified as benign. -

Oct 21, 2019

Quest Diagnostics Nichols Institute San Juan Capistrano

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 16, 2014

Eurofins Ntd Llc (ga)

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Benign:2

Apr 20, 2018

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. -

Mar 03, 2021

Sema4, Sema4

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:curation

- -

Aplastic anemia

Uncertain:1

Jan 13, 2019

Baylor Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was determined to be of uncertain significance according to ACMG Guidelines, 2015 [PMID:25741868]. -

Malignant tumor of breast

Uncertain:1

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The NBN p.Ile439Met variant was identified in 2 of 3282 proband chromosomes (frequency: 0.0006) from individuals or families with Lynch syndrome or endometrial carcinoma (Yurgelun 2015, Ring 2016). The variant was also identified in dbSNP (ID: rs28538230) as "With Likely benign allele", ClinVar (classified as likely benign by GeneDx, Ambry Genetics, Invitae, and three other clinical laboratories), and the Zhejiang University Databse (1x). The variant was not identified in Cosmic or LOVD 3.0 databases. The variant was identified in control databases in 96 of 277020 chromosomes at a frequency of 0.0004, increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: African in 95 of 24024 chromosomes (freq: 0.004), Latino in 1 of 34398 chromosomes (freq: 0.00003), while the variant was not observed in the Other, European, Ashkenazi Jewish, East Asian, Finnish, or South Asian populations. The p.Ile439 residue is not conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; however, this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence but 2 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict a greater than 10% difference in splicing; however, this is not very predictive of pathogenicity. In summary, based on the above information, the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

not provided

Benign:1

Nov 04, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 27443514, 25980754, 23555315, 26979391) -

NBN-related disorder

Benign:1

Apr 30, 2024

PreventionGenetics, part of Exact Sciences

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

This variant is classified as likely benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.063

BayesDel_addAF

Benign

-0.60

BayesDel_noAF

Benign

-0.64

CADD

Benign

(source)

DANN

Benign

0.30

DEOGEN2

Benign

0.068

T;T

Eigen

Benign

-1.3

Eigen_PC

Benign

-1.3

FATHMM_MKL

Benign

0.028

LIST_S2

Benign

0.63

T;T

M_CAP

Benign

0.013

MetaRNN

Benign

0.0043

T;T

MetaSVM

Benign

-1.1

MutationAssessor

Benign

1.4

L;.

PhyloP100

0.015

PrimateAI

Benign

0.27

PROVEAN

Benign

-0.15

N;N

REVEL

Benign

0.010

Sift

Benign

0.098

T;T

Sift4G

Benign

0.16

T;T

Polyphen

0.0010

B;.

Vest4

0.073

MVP

0.42

MPC

0.069

ClinPred

0.0030

GERP RS

-1.0

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.034

gMVP

0.11

Mutation Taster

=97/3

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