8-89970462-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3

The NM_002485.5(NBN):c.798G>A(p.Pro266Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000229 in 1,613,832 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P266P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000025 ( 0 hom. )

Consequence

NBN
NM_002485.5 synonymous

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:6

Conservation

PhyloP100: 0.684

Publications

2 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: Uncertain_significance. The variant received 1 ACMG points.

PP3

Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBN	NM_002485.5 link	c.798G>A	p.Pro266Pro	synonymous_variant	Exon 7 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.798G>A	p.Pro266Pro	synonymous_variant	Exon 7 of 16	1	NM_002485.5	ENSP00000265433.4		O60934

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.0000147

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000119

AC:

AN:

251280

AF XY:

0.0000221

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00000880

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000246

AC:

AN:

1461702

Hom.:

Cov.:

AF XY:

0.0000316

AC XY:

AN XY:

727162

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33472

American (AMR)

AF:

0.00

AC:

AN:

44710

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39676

South Asian (SAS)

AF:

0.000128

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53410

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000189

AC:

AN:

1111898

Other (OTH)

AF:

0.0000331

AC:

AN:

60384

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.463

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:

0.00000657

AC:

AN:

152130

Hom.:

Cov.:

AF XY:

0.0000135

AC XY:

AN XY:

74318

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41420

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5206

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10602

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68012

Other (OTH)

AF:

0.00

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Alfa

AF:

0.0000329

Hom.:

Bravo

AF:

0.0000151

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:6

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency

Uncertain:2

Dec 22, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change affects codon 266 of the NBN mRNA. It is a 'silent' change, meaning that it does not change the encoded amino acid sequence of the NBN protein. This variant is present in population databases (rs368786672, 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: 382019). Studies have shown that this variant is associated with inconclusive levels of altered splicing (Invitae). 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. -

Nov 07, 2021

Genome-Nilou Lab

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Feb 25, 2025

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.798G>A alters a non-conserved nucleotide resulting in a synonymous change. Several computational tools predict a significant impact on normal splicing: Three predict the variant creates a 3' acceptor site. While internal RNA splicing data have been obtained for this variant (Labcorp Genetics, formerly Invitae) at this time the results are inconclusive. The variant allele was found at a frequency of 1.2e-05 in 251280 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.798G>A in individuals affected with Nijmegen Breakage Syndrome have been reported. The following publications have been ascertained in the context of this evaluation (PMID: 30287823, 36243179). ClinVar contains an entry for this variant (Variation ID: 382019). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:1

Dec 22, 2022

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis suggests this variant may impact gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; Observed in an individual with breast cancer but also in an unaffected control (Momozawa et al., 2018); This variant is associated with the following publications: (PMID: 30287823) -

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.Pro266= variant was not identified in the literature. The variant was identified in dbSNP (rs368786672) as â€šÃ„Ãºwith other alleleâ€šÃ„Ã¹, ClinVar (classified as likely benign by GeneDx and Ambry Genetics; and as uncertain significance by Invitae and Ambry Genetics) and LOVD 3.0 (observed 2x). The variant was identified in control databases in 3 of 246,064 chromosomes at a frequency of 0.000012 (Genome Aggregation Database Feb 27, 2017). The variant was observed in the following populations: European in 1 of 111,586 chromosomes (freq: 0.000009) and South Asian in 2 of 30,780 chromosomes (freq: 0.00007), but not in the African, Other, Latino, Ashkenazi Jewish, East Asian or Finnish populations. The p.Pro266= variant is not expected to have clinical significance because it does not result in a change of amino acid and it occurs at a non-conserved nucleotide outside of the splicing consensus sequence. However, 3 of 4 in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) predict the introduction of a cryptic splice site; this information is not predictive enough to assume 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. -

Hereditary cancer-predisposing syndrome

Uncertain:1

Apr 17, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.798G>A variant (also known as p.P266P), located in coding exon 7 of the NBN gene, results from a G to A substitution at nucleotide position 798. This nucleotide substitution does not change the amino acid at codon 266. This alteration was observed with an allele frequency of 0.00014 in 7,051 unselected female breast cancer patients and was not observed in 11,241 female controls of Japanese ancestry. In addition, it was not observed in unselected male breast cancer patients and was observed with an allele frequency of 0.0001 in 12490 male controls of Japanese ancestry (Momozawa Y et al. Nat Commun, 2018 10;9:4083). This nucleotide position is poorly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will result in the creation or strengthening of a novel splice acceptor site; however, direct evidence is insufficient at this time (Ambry internal data). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.49

CADD

Benign

(source)

DANN

Benign

0.43

PhyloP100

0.68

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Mutation Taster

=100/0

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.70

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.70

Position offset: -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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over