8-89943263-T-C

Variant names:

• chr8-89943263-T-C
• rs878854510
• NM_002485.5:c.2174A>G

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_002485.5(NBN):​c.2174A>G​(p.Gln725Arg) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,490 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 3.73

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.29507542).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBN	NM_002485.5	c.2174A>G	p.Gln725Arg	missense_variant	Exon 14 of 16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.2174A>G	p.Gln725Arg	missense_variant	Exon 14 of 16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000796 AC: 2 AN: 251368 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135858

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000578

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: 0.00000205 AC: 3 AN: 1461490 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 727048

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000671

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 Cov.: 32

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:2

Aug 15, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glutamine, which is neutral and polar, with arginine, which is basic and polar, at codon 725 of the NBN protein (p.Gln725Arg). This variant is present in population databases (no rsID available, 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: 925004). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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

- -

Aplastic anemia Uncertain:1

Feb 03, 2024

Baylor Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Uncertain:1

Jun 14, 2023

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 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

May 06, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Q725R variant (also known as c.2174A>G), located in coding exon 14 of the NBN gene, results from an A to G substitution at nucleotide position 2174. The glutamine at codon 725 is replaced by arginine, an amino acid with highly similar properties. This amino acid position is well 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	0.13
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.28
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T;T;.
Eigen	Benign	0.067
Eigen_PC	Uncertain	0.24
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Benign	0.60	T;T;T
M_CAP	Benign	0.024	T
MetaRNN	Benign	0.30	T;T;T
MetaSVM	Benign	-0.74	T
MutationAssessor	Uncertain	2.3	M;.;.
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-1.9	N;N;.
REVEL	Benign	0.12
Sift	Uncertain	0.020	D;D;.
Sift4G	Benign	0.070	T;T;T
Polyphen		0.020	B;.;.
Vest4		0.14
MutPred		0.61		Gain of disorder (P = 0.193);.;.;
MVP		0.74
MPC		0.11
ClinPred		0.44	T
GERP RS		5.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.10
gMVP		0.26

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

Other links and lift over

dbSNP: rs878854510; hg19: chr8-90955491;