rs1554558393

Positions:

• chr8-89953471-G-A

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_002485.5(NBN):​c.1618C>T​(p.His540Tyr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,440 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 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:3
• Conservation: PhyloP100: 0.0150

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 -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.043924987).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.1618C>T	p.His540Tyr	missense_variant	11/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.1618C>T	p.His540Tyr	missense_variant	11/16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461440 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727040

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

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	Labcorp Genetics (formerly Invitae), Labcorp	Oct 27, 2020	In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. 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 (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with an NBN-related disease. This sequence change replaces histidine with tyrosine at codon 540 of the NBN protein (p.His540Tyr). The histidine residue is weakly conserved and there is a moderate physicochemical difference between histidine and tyrosine. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 30, 2022

The p.H540Y variant (also known as c.1618C>T), located in coding exon 11 of the NBN gene, results from a C to T substitution at nucleotide position 1618. The histidine at codon 540 is replaced by tyrosine, an amino acid with similar properties. In one study, this alteration was observed in 1/3236 cases with invasive epithelial ovarian cancer and 0/3431 controls (Ramus SJ et al. J Natl Cancer Inst, 2015 Nov;107:). This amino acid position is poorly 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	0.066
BayesDel_addAF	Benign	-0.24	T
BayesDel_noAF	Benign	-0.58
CADD	Benign	2.9
DANN	Benign	0.20
DEOGEN2	Benign	0.056	T;T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.4
FATHMM_MKL	Benign	0.028	N
LIST_S2	Benign	0.68	T;T
M_CAP	Benign	0.0083	T
MetaRNN	Benign	0.044	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.69	N;.
PrimateAI	Benign	0.31	T
PROVEAN	Benign	-0.080	N;N
REVEL	Benign	0.028
Sift	Benign	1.0	T;T
Sift4G	Benign	0.16	T;T
Polyphen		0.014	B;.
Vest4		0.15
MutPred		0.16		Gain of methylation at K544 (P = 0.0568);.;
MVP		0.41
MPC		0.078
ClinPred		0.015	T
GERP RS		0.19
Varity_R		0.019
gMVP		0.074

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: rs1554558393; hg19: chr8-90965699; COSMIC: COSV55374312; COSMIC: COSV55374312;