8-89970554-T-C

Position:

• chr8-89970554-T-C

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 0P and 1B. BP4

The NM_002485.5(NBN):​c.706A>G​(p.Lys236Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,460,890 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 3.55

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -1 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.35628852).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.706A>G	p.Lys236Glu	missense_variant	7/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.706A>G	p.Lys236Glu	missense_variant	7/16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1460890 Hom.: 0 Cov.: 31 AF XY: 0.00000275 AC XY: 2 AN XY: 726796

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

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

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Sep 15, 2023	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. ClinVar contains an entry for this variant (Variation ID: 411778). This missense change has been observed in individual(s) with breast cancer, bone marrow failure and/or myelodysplastic syndrome (PMID: 25239263, 35039564). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with glutamic acid, which is acidic and polar, at codon 236 of the NBN protein (p.Lys236Glu). -

Hereditary cancer-predisposing syndrome Uncertain:2

Uncertain significance, criteria provided, single submitter	curation	Sema4, Sema4	Sep 16, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	May 23, 2024	The p.K236E variant (also known as c.706A>G), located in coding exon 7 of the NBN gene, results from an A to G substitution at nucleotide position 706. The lysine at codon 236 is replaced by glutamic acid, an amino acid with similar properties. In a study of patients with idiopathic bone marrow failure or myelodysplastic syndrome, this variant was seen in an 18-year-old male with bone marrow failure (Zhang MY et al. Haematologica. 2015 Jan;100:42-8)This amino acid position is well conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on the available evidence, the clinical significance of this variant remains unclear. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jun 14, 2019

Not observed in large population cohorts (Lek et al., 2016); In silico analysis, which includes protein predictors and evolutionary conservation, supports a deleterious effect; This variant is associated with the following publications: (PMID: 25239263) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.35
BayesDel_addAF	Uncertain	0.073	D
BayesDel_noAF	Benign	-0.13
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.14	T;T;.;.
Eigen	Uncertain	0.58
Eigen_PC	Uncertain	0.58
FATHMM_MKL	Uncertain	0.87	D
LIST_S2	Uncertain	0.89	D;D;D;D
M_CAP	Benign	0.053	D
MetaRNN	Benign	0.36	T;T;T;T
MetaSVM	Uncertain	-0.097	T
MutationAssessor	Pathogenic	3.0	M;.;.;.
PrimateAI	Uncertain	0.52	T
PROVEAN	Uncertain	-2.5	D;N;D;N
REVEL	Benign	0.25
Sift	Uncertain	0.0050	D;D;D;D
Sift4G	Uncertain	0.022	D;D;D;.
Polyphen		1.0	D;.;.;.
Vest4		0.51
MutPred		0.40		Loss of MoRF binding (P = 0.0068);.;.;.;
MVP		0.87
MPC		0.21
ClinPred		0.97	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.43
gMVP		0.57

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: rs1060503482; hg19: chr8-90982782;