rs587782297

Positions:

• chr8-89947867-C-A
• chr8-89947867-C-G
• chr8-89947867-C-T

Variant summary

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

The NM_002485.5(NBN):​c.1871G>T​(p.Arg624Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000702 in 1,423,664 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: 7.0e-7 (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=0.03912565).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.1871G>T	p.Arg624Leu	missense_variant	12/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.1871G>T	p.Arg624Leu	missense_variant	12/16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 7.02e-7 AC: 1 AN: 1423664 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 708784

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: 0.00

Gnomad4 OTH exome AF: 0.0000170

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	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 04, 2019	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 (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 and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with NBN-related conditions. ClinVar contains an entry for this variant (Variation ID: 480051). This variant is not present in population databases (ExAC no frequency). This sequence change replaces arginine with leucine at codon 624 of the NBN protein (p.Arg624Leu). The arginine residue is weakly conserved and there is a moderate physicochemical difference between arginine and leucine. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 19, 2016

The p.R624L variant (also known as c.1871G>T), located in coding exon 12 of the NBN gene, results from a G to T substitution at nucleotide position 1871. The arginine at codon 624 is replaced by leucine, an amino acid with dissimilar properties. This variant was not reported in population based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), NHLBI Exome Sequencing Project (ESP), and 1000 Genomes Project. In the ESP, this variant was not observed in 6491 samples (12982 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.001% (greater than 175000 alleles tested) in our clinical cohort. 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	0.080
BayesDel_addAF	Benign	-0.26	T
BayesDel_noAF	Benign	-0.61
CADD	Benign	6.1
DANN	Benign	0.25
DEOGEN2	Benign	0.054	T;T;.
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.1
FATHMM_MKL	Benign	0.44	N
LIST_S2	Benign	0.34	T;T;T
M_CAP	Benign	0.0093	T
MetaRNN	Benign	0.039	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	0.0	N;.;.
PrimateAI	Benign	0.23	T
PROVEAN	Benign	-0.16	N;N;.
REVEL	Benign	0.040
Sift	Benign	0.83	T;T;.
Sift4G	Benign	0.54	T;T;T
Polyphen		0.0010	B;.;.
Vest4		0.23
MutPred		0.25		Loss of helix (P = 0.0237);.;.;
MVP		0.30
MPC		0.082
ClinPred		0.042	T
GERP RS		0.22
Varity_R		0.032
gMVP		0.085

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.13		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: rs587782297; hg19: chr8-90960095;