chr8-89970533-C-A

Position:

• chr8-89970533-C-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.727G>T​(p.Val243Phe) 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 (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -0.819

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 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=0.22761264).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.727G>T	p.Val243Phe	missense_variant	7/16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.727G>T	p.Val243Phe	missense_variant	7/16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Oct 30, 2014

The p.V243F variant (also known as c.727G>T), located in coding exon 7 of the NBN gene, results from a G to T substitution at nucleotide position 727. The valine at codon 243 is replaced by phenylalanine, an amino acid with highly similar 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 6503 samples (13006 alleles) with coverage at this position. To date, this alteration has been detected with an allele frequency of approximately 0.005% (greater than 22,000 alleles tested) in our clinical cohort. This amino acid position is not 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 p.V243F remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.025	T
BayesDel_noAF	Benign	-0.27
CADD	Benign	13
DANN	Benign	0.96
DEOGEN2	Benign	0.17	T;T;.;.
Eigen	Benign	-0.69
Eigen_PC	Benign	-0.86
FATHMM_MKL	Benign	0.072	N
LIST_S2	Uncertain	0.89	D;T;D;D
M_CAP	Benign	0.053	D
MetaRNN	Benign	0.23	T;T;T;T
MetaSVM	Benign	-0.74	T
MutationAssessor	Uncertain	2.0	M;.;.;.
PrimateAI	Benign	0.32	T
PROVEAN	Benign	-2.1	N;N;N;N
REVEL	Benign	0.25
Sift	Uncertain	0.029	D;D;T;D
Sift4G	Benign	0.31	T;T;T;.
Polyphen		0.95	P;.;.;.
Vest4		0.44
MutPred		0.37		Loss of helix (P = 0.0626);.;.;.;
MVP		0.71
MPC		0.17
ClinPred		0.33	T
GERP RS		-4.0
Varity_R		0.12
gMVP		0.58

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs786203253; hg19: chr8-90982761;