chr8-89981403-T-G

Position:

• chr8-89981403-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_002485.5(NBN):​c.292A>C​(p.Thr98Pro) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar 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: 4.22

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 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.938

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.292A>C	p.Thr98Pro	missense_variant	3/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.292A>C	p.Thr98Pro	missense_variant	3/16	1	NM_002485.5	ENSP00000265433	P1

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 03, 2022

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. 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: "Probably Damaging"; Align-GVGD: "Class C0"). ClinVar contains an entry for this variant (Variation ID: 411740). This variant has not been reported in the literature in individuals affected with NBN-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces threonine, which is neutral and polar, with proline, which is neutral and non-polar, at codon 98 of the NBN protein (p.Thr98Pro). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 29, 2017

The p.T98P variant (also known as c.292A>C), located in coding exon 3 of the NBN gene, results from an A to C substitution at nucleotide position 292. The threonine at codon 98 is replaced by proline, 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 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	0.75
BayesDel_addAF	Pathogenic	0.30	D
BayesDel_noAF	Pathogenic	0.19
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.60	D;T;.;.;.
Eigen	Pathogenic	0.71
Eigen_PC	Uncertain	0.63
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.86	D;T;D;D;D
M_CAP	Uncertain	0.14	D
MetaRNN	Pathogenic	0.94	D;D;D;D;D
MetaSVM	Pathogenic	0.89	D
MutationAssessor	Pathogenic	3.7	H;.;.;.;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.36	T
PROVEAN	Uncertain	-3.8	D;D;D;D;D
REVEL	Pathogenic	0.76
Sift	Uncertain	0.0030	D;D;D;D;T
Sift4G	Uncertain	0.010	D;D;D;.;D
Polyphen		1.0	D;.;.;.;.
Vest4		0.49
MutPred		0.77		Loss of phosphorylation at T98 (P = 0.0523);.;Loss of phosphorylation at T98 (P = 0.0523);.;.;
MVP		0.98
MPC		0.45
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.96
gMVP		0.77

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

Publications

LitVar

Other links and lift over

dbSNP: rs1060503453; hg19: chr8-90993631;