NM_002485.5:c.442A>G

Variant names:

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM2PP3_Strong

The NM_002485.5(NBN):c.442A>G(p.Thr148Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,188 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. T148S) has been classified as Uncertain significance.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

NBN
NM_002485.5 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 6.08

Publications

3 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_pathogenic. The variant received 6 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

PP3

MetaRNN computational evidence supports a deleterious effect, 0.943

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBN	NM_002485.5 link	c.442A>G	p.Thr148Ala	missense_variant	Exon 4 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.442A>G	p.Thr148Ala	missense_variant	Exon 4 of 16	1	NM_002485.5	ENSP00000265433.4		O60934

Frequencies

GnomAD3 genomes

Cov.:

GnomAD4 exome

AF:

6.84e-7

AC:

AN:

1461188

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726946

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33458

American (AMR)

AF:

0.00

AC:

AN:

44720

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39610

South Asian (SAS)

AF:

0.00

AC:

AN:

86244

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53344

Middle Eastern (MID)

AF:

0.000174

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1111562

Other (OTH)

AF:

0.00

AC:

AN:

60368

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

GnomAD4 genome

Cov.:

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:3

Sep 17, 2021

Natera, Inc.

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

- -

Feb 26, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with alanine, which is neutral and non-polar, at codon 148 of the NBN protein (p.Thr148Ala). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with clinical features of Nijmegen breakage syndrome (PMID: 31729086). ClinVar contains an entry for this variant (Variation ID: 411773). 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. Experimental studies have shown that this missense change affects NBN function (PMID: 31729086). 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:2

Oct 02, 2024

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.442A>G (p.Thr148Ala) results in a non-conservative amino acid change located in the BRCT domain (BRCT domain) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251282 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.442A>G has been reported in the literature in three homozygous individuals affected with infertility (Fivet_2020) but has not been reported in any individuals with Nijmegen Breakage Syndrome. These report(s) do 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: 31729086). ClinVar contains an entry for this variant (Variation ID: 411773). Based on the evidence outlined above, the variant was classified as uncertain significance. -

May 04, 2022

Mendelics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Hereditary cancer-predisposing syndrome

Uncertain:1

Mar 02, 2023

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.T148A variant (also known as c.442A>G), located in coding exon 4 of the NBN gene, results from an A to G substitution at nucleotide position 442. The threonine at codon 148 is replaced by alanine, an amino acid with similar properties. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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

Pathogenic

0.73

BayesDel_addAF

Pathogenic

0.36

BayesDel_noAF

Pathogenic

0.28

CADD

Pathogenic

(source)

DANN

Uncertain

1.0

DEOGEN2

Uncertain

0.58

D;T;.;.

Eigen

Pathogenic

0.83

Eigen_PC

Pathogenic

0.79

FATHMM_MKL

Uncertain

0.95

LIST_S2

Uncertain

0.88

D;T;D;D

M_CAP

Uncertain

0.095

MetaRNN

Pathogenic

0.94

D;D;D;D

MetaSVM

Uncertain

0.32

MutationAssessor

Pathogenic

2.9

M;.;.;.

PhyloP100

6.1

PrimateAI

Uncertain

0.59

PROVEAN

Uncertain

-4.2

D;D;D;D

REVEL

Pathogenic

0.85

Sift

Pathogenic

0.0

D;D;D;D

Sift4G

Pathogenic

0.0

D;D;.;D

Polyphen

1.0

D;.;.;.

Vest4

0.94

MutPred

0.85

Loss of sheet (P = 0.1158);.;.;.;

MVP

0.94

MPC

0.23

ClinPred

0.99

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.1

Varity_R

0.75

gMVP

0.89

Mutation Taster

=15/85

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.080

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

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over