8-89953293-G-C

Variant names:

• chr8-89953293-G-C
• rs775848374
• NM_002485.5:c.1796C>G

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_002485.5(NBN):​c.1796C>G​(p.Thr599Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,460,998 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T599I) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 0.268
• Publications: 0 publications found

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

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.034479767).
• BP6: Variant 8-89953293-G-C is Benign according to our data. Variant chr8-89953293-G-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 233713.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002485.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NBN	NM_002485.5	MANE Select	c.1796C>G	p.Thr599Arg	missense	Exon 11 of 16	NP_002476.2
	NBN	NM_001024688.3		c.1550C>G	p.Thr517Arg	missense	Exon 12 of 17	NP_001019859.1
	NBN	NM_001440379.1		c.1550C>G	p.Thr517Arg	missense	Exon 11 of 16	NP_001427308.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NBN	ENST00000265433.8	TSL:1 MANE Select	c.1796C>G	p.Thr599Arg	missense	Exon 11 of 16	ENSP00000265433.4
	NBN	ENST00000697309.1		c.1796C>G	p.Thr599Arg	missense	Exon 11 of 15	ENSP00000513244.1
	NBN	ENST00000697293.1		c.1796C>G	p.Thr599Arg	missense	Exon 11 of 17	ENSP00000513230.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250800 AF XY: 0.00000737

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000544

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1460998 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726850

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26116

East Asian (EAS) AF: 0.000101 AC: 4 AN: 39642

South Asian (SAS) AF: 0.00 AC: 0 AN: 86244

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52932

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111742

Other (OTH) AF: 0.00 AC: 0 AN: 60370

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:3

Nov 07, 2021

Genome-Nilou Lab

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Apr 14, 2020

Natera, Inc.

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

Feb 03, 2025

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 arginine, which is basic and polar, at codon 599 of the NBN protein (p.Thr599Arg). This variant is present in population databases (rs775848374, gnomAD 0.01%). This missense change has been observed in individual(s) with breast cancer (PMID: 34326862). ClinVar contains an entry for this variant (Variation ID: 233713). An algorithm developed to predict the effect of missense changes on protein structure and function outputs the following: PolyPhen-2: "Benign". The arginine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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.

Ovarian cancer Benign:1

Jan 01, 2022

Laboratory of Molecular Epidemiology of Birth Defects, West China Second University Hospital, Sichuan University

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Hereditary cancer-predisposing syndrome Benign:1

Mar 21, 2024

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.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.078
BayesDel_addAF	Benign	-0.36	T
BayesDel_noAF	Benign	-0.52
CADD	Benign	16
DANN	Benign	0.90
DEOGEN2	Benign	0.071	T
Eigen	Benign	-0.84
Eigen_PC	Benign	-0.68
FATHMM_MKL	Benign	0.051	N
LIST_S2	Benign	0.63	T
M_CAP	Benign	0.0091	T
MetaRNN	Benign	0.034	T
MetaSVM	Benign	-0.97	T
MutationAssessor	Benign	1.3	L
PhyloP100		0.27
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-0.30	N
REVEL	Benign	0.070
Sift	Benign	0.90	T
Sift4G	Benign	0.69	T
Polyphen		0.0010	B
Vest4		0.10
MutPred		0.19		Loss of glycosylation at T599 (P = 0.0437)
MVP		0.62
MPC		0.076
ClinPred		0.027	T
GERP RS		3.3
PromoterAI		-0.0085	Neutral
Varity_R		0.024
gMVP		0.11
Mutation Taster		=91/9	polymorphism

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

Other links and lift over

dbSNP: rs775848374; hg19: chr8-90965521;