rs1554569035

chr8-89982744-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_002485.5(NBN):c.149C>T(p.Ala50Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 16/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. A50A) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3 O:1
• Conservation: PhyloP100: 3.19

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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.090242684).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5	c.149C>T	p.Ala50Val	missense_variant	2/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.149C>T	p.Ala50Val	missense_variant	2/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:2 Other:1

not provided, no classification provided	phenotyping only	GenomeConnect - Invitae Patient Insights Network	-	Variant interpreted as Uncertain significance and reported on 06-14-2018 by Invitae. GenomeConnect-Invitae Patient Insights Network assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. Registry team members make no attempt to reinterpret the clinical significance of the variant. Phenotypic details are available under supporting information. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 23, 2022	This sequence change replaces alanine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 50 of the NBN protein (p.Ala50Val). 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: 530745). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The valine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -
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

Apr 14, 2023

The p.A50V variant (also known as c.149C>T), located in coding exon 2 of the NBN gene, results from a C to T substitution at nucleotide position 149. The alanine at codon 50 is replaced by valine, an amino acid with similar properties. This amino acid position is not well conserved in available vertebrate species, and valine is the reference amino acid in other 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	0.12
BayesDel_addAF	Benign	-0.11	T
BayesDel_noAF	Benign	-0.40
Cadd	Benign	17
Dann	Benign	0.85
DEOGEN2	Benign	0.19	T;.
Eigen	Benign	-0.79
Eigen_PC	Benign	-0.51
FATHMM_MKL	Benign	0.30	N
LIST_S2	Benign	0.76	T;T
M_CAP	Benign	0.019	T
MetaRNN	Benign	0.090	T;T
MetaSVM	Benign	-0.84	T
MutationAssessor	Benign	-1.0	N;.
MutationTaster	Benign	1.0	D;N
PrimateAI	Benign	0.34	T
PROVEAN	Benign	1.0	N;N
REVEL	Benign	0.18
Sift	Benign	1.0	T;T
Sift4G	Benign	1.0	T;T
Polyphen		0.0010	B;.
Vest4		0.16
MutPred		0.59		Gain of sheet (P = 0.0827);Gain of sheet (P = 0.0827);
MVP		0.83
MPC		0.068
ClinPred		0.39	T
GERP RS		2.9
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.038
gMVP		0.29

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: rs1554569035; hg19: chr8-90994972;