chr8-89947864-T-C

Position:

• chr8-89947864-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.1874A>G​(p.Glu625Gly) 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. 14/21 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. E625K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.67

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=0.19250101).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5	c.1874A>G	p.Glu625Gly	missense_variant	12/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.1874A>G	p.Glu625Gly	missense_variant	12/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1427148 Hom.: 0 Cov.: 26 AF XY: 0.00 AC XY: 0 AN XY: 710436

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: 0.00

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 16, 2022

This variant has not been reported in the literature in individuals affected with NBN-related conditions. 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 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"). ClinVar contains an entry for this variant (Variation ID: 530723). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glutamic acid, which is acidic and polar, with glycine, which is neutral and non-polar, at codon 625 of the NBN protein (p.Glu625Gly). -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 18, 2021

The p.E625G variant (also known as c.1874A>G), located in coding exon 12 of the NBN gene, results from an A to G substitution at nucleotide position 1874. The glutamic acid at codon 625 is replaced by glycine, an amino acid with similar properties. This amino acid position is conserved. 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	0.081
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.46
CADD	Benign	19
DANN	Uncertain	0.99
DEOGEN2	Benign	0.32	T;T;.
Eigen	Benign	-0.55
Eigen_PC	Benign	-0.60
FATHMM_MKL	Benign	0.56	D
LIST_S2	Benign	0.57	T;T;T
M_CAP	Benign	0.030	D
MetaRNN	Benign	0.19	T;T;T
MetaSVM	Benign	-0.88	T
MutationAssessor	Benign	1.9	L;.;.
MutationTaster	Benign	0.67	D;D
PrimateAI	Benign	0.44	T
PROVEAN	Benign	-1.6	N;N;.
REVEL	Benign	0.027
Sift	Uncertain	0.0050	D;D;.
Sift4G	Uncertain	0.042	D;T;T
Polyphen		0.80	P;.;.
Vest4		0.32
MutPred		0.33		Loss of stability (P = 0.0156);.;.;
MVP		0.79
MPC		0.24
ClinPred		0.42	T
GERP RS		1.4
Varity_R		0.047
gMVP		0.20

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		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: rs1554556929; hg19: chr8-90960092;