chr8-89943287-G-C

Variant names:

• chr8-89943287-G-C
• rs1554555764
• NM_002485.5:c.2150C>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002485.5(NBN):​c.2150C>G​(p.Thr717Arg) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign 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. T717I) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 4.93
• 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: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.24479577).

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.2150C>G	p.Thr717Arg	missense	Exon 14 of 16	NP_002476.2
	NBN	NM_001024688.3		c.1904C>G	p.Thr635Arg	missense	Exon 15 of 17	NP_001019859.1
	NBN	NM_001440379.1		c.1904C>G	p.Thr635Arg	missense	Exon 14 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.2150C>G	p.Thr717Arg	missense	Exon 14 of 16	ENSP00000265433.4
	NBN	ENST00000697309.1		c.2150C>G	p.Thr717Arg	missense	Exon 14 of 15	ENSP00000513244.1
	NBN	ENST00000697293.1		c.2150C>G	p.Thr717Arg	missense	Exon 14 of 17	ENSP00000513230.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:1

Apr 14, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. 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 tolerated. This sequence change replaces threonine, which is neutral and polar, with arginine, which is basic and polar, at codon 717 of the NBN protein (p.Thr717Arg). This variant is not present in population databases (gnomAD no frequency). 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: 1786740).

Hereditary cancer-predisposing syndrome Uncertain:1

Nov 12, 2021

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.T717R variant (also known as c.2150C>G), located in coding exon 14 of the NBN gene, results from a C to G substitution at nucleotide position 2150. The threonine at codon 717 is replaced by arginine, an amino acid with similar properties. This amino acid position is conserved. 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 v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.16	T
BayesDel_noAF	Benign	-0.47
CADD	Benign	21
DANN	Uncertain	0.98
DEOGEN2	Benign	0.16	T
Eigen	Benign	-0.48
Eigen_PC	Benign	-0.37
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Benign	0.76	T
M_CAP	Benign	0.021	T
MetaRNN	Benign	0.24	T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	0.90	L
PhyloP100		4.9
PrimateAI	Benign	0.35	T
PROVEAN	Benign	-1.4	N
REVEL	Benign	0.079
Sift	Benign	0.053	T
Sift4G	Uncertain	0.0070	D
Polyphen		0.0020	B
Vest4		0.12
MutPred		0.49		Loss of helix (P = 0.0093)
MVP		0.62
MPC		0.079
ClinPred		0.53	D
GERP RS		3.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.092
gMVP		0.36
Mutation Taster		=92/8	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: rs1554555764; hg19: chr8-90955515;