8-89953398-T-C

Position:

• chr8-89953398-T-C

Variant summary

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

The NM_002485.5(NBN):​c.1691A>G​(p.Glu564Gly) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 12/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E564K) has been classified as Benign.

• 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: 3.62

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=0.22171149).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.1691A>G	p.Glu564Gly	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.1691A>G	p.Glu564Gly	missense_variant	11/16	1	NM_002485.5	ENSP00000265433	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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

Aug 28, 2021

This sequence change replaces glutamic acid with glycine at codon 564 of the NBN protein (p.Glu564Gly). The glutamic acid residue is moderately conserved and there is a moderate physicochemical difference between glutamic acid and glycine. This variant is not present in population databases (ExAC 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: 461519). 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: "Deleterious"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). 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. -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 07, 2023

The p.E564G variant (also known as c.1691A>G), located in coding exon 11 of the NBN gene, results from an A to G substitution at nucleotide position 1691. The glutamic acid at codon 564 is replaced by glycine, an amino acid with similar properties. This amino acid position is well 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	0.097
BayesDel_addAF	Benign	-0.036	T
BayesDel_noAF	Benign	-0.29
CADD	Uncertain	23
DANN	Uncertain	1.0
DEOGEN2	Benign	0.39	T;T
Eigen	Benign	0.13
Eigen_PC	Benign	0.17
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Benign	0.77	T;T
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.22	T;T
MetaSVM	Benign	-0.90	T
MutationAssessor	Benign	2.0	M;.
MutationTaster	Benign	0.91	N;N
PrimateAI	Benign	0.38	T
PROVEAN	Uncertain	-3.4	D;D
REVEL	Benign	0.050
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.018	D;D
Polyphen		0.93	P;.
Vest4		0.28
MutPred		0.30		Gain of loop (P = 0.0079);.;
MVP		0.81
MPC		0.36
ClinPred		0.91	D
GERP RS		4.4
Varity_R		0.30
gMVP		0.39

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: rs1554558323; hg19: chr8-90965626;