rs587781939

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_002485.5(NBN):c.52C>A(p.Leu18Ile) variant causes a missense change. The variant allele was found at a frequency of 0.00000806 in 1,613,318 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. L18L) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000048 ( 0 hom. )

Consequence

NBN
NM_002485.5 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:7

Conservation

PhyloP100: 3.83

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.22601774).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5 linkuse as main transcript	c.52C>A	p.Leu18Ile	missense_variant	2/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8 linkuse as main transcript	c.52C>A	p.Leu18Ile	missense_variant	2/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes

AF:

0.0000394

AC:

AN:

152110

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000145

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251306

Hom.:

AF XY:

0.00000736

AC XY:

AN XY:

135822

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS 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:

0.00000479

AC:

AN:

1461208

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

726938

show subpopulations

Gnomad4 AFR exome

AF:

0.000209

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000394

AC:

AN:

152110

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74316

show subpopulations

Gnomad4 AFR

AF:

0.000145

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000991

Hom.:

Bravo

AF:

0.0000642

ExAC

AF:

0.0000247

AC:

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, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Jul 29, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Nov 01, 2022	This sequence change replaces leucine, which is neutral and non-polar, with isoleucine, which is neutral and non-polar, at codon 18 of the NBN protein (p.Leu18Ile). This variant is present in population databases (rs587781939, 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: 141689). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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 specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Jul 13, 2023

Variant summary: NBN c.52C>A (p.Leu18Ile) results in a conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251306 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.52C>A has been reported in the literature in a setting of muligene panel testing in an individual affected with breast cancer, without strong evidence for causality (George_2021). This report does not provide unequivocal conclusions about association of the variant with Hereditary Breast And Ovarian Cancer Syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Six submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and all classified 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

Aug 25, 2023

- -

not provided

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Feb 14, 2020

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 -

Hereditary cancer-predisposing syndrome

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 01, 2023

The p.L18I variant (also known as c.52C>A), located in coding exon 2 of the NBN gene, results from a C to A substitution at nucleotide position 52. The leucine at codon 18 is replaced by isoleucine, an amino acid with highly similar properties. This variant was identified in an individual from Barbados who was diagnosed with breast cancer at age 39 (George SHL et al. JAMA Netw Open, 2021 Mar;4:e210307). 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: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.11

BayesDel_addAF

Benign

-0.36

BayesDel_noAF

Benign

-0.46

Cadd

Uncertain

Dann

Uncertain

0.99

DEOGEN2

Benign

0.16

T;.

Eigen

Uncertain

0.25

Eigen_PC

Uncertain

0.29

FATHMM_MKL

Uncertain

0.86

LIST_S2

Benign

0.81

T;T

M_CAP

Benign

0.016

MetaRNN

Benign

0.23

T;T

MetaSVM

Benign

-0.99

MutationAssessor

Benign

1.9

M;.

MutationTaster

Benign

1.0

D;D

PrimateAI

Uncertain

0.71

PROVEAN

Benign

-1.2

N;N

REVEL

Benign

0.16

Sift

Benign

0.072

T;T

Sift4G

Benign

0.12

T;T

Polyphen

0.98

D;.

Vest4

0.40

MVP

0.61

MPC

0.34

ClinPred

0.46

GERP RS

5.1

Varity_R

0.19

gMVP

0.45

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over