rs775848374

Positions:

• chr8-89953293-G-A
• chr8-89953293-G-C

Variant summary

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

The ENST00000265433.8(NBN):​c.1796C>T​(p.Thr599Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,460,998 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. T599R) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: NBN ENST00000265433.8 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:2
• Conservation: PhyloP100: 0.268

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 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=0.06585926).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.1796C>T	p.Thr599Ile	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.1796C>T	p.Thr599Ile	missense_variant	11/16	1	NM_002485.5	ENSP00000265433	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1460998 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 726850

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

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: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, single submitter

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 26, 2018	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 disease. This variant is not present in population databases (ExAC no frequency). This sequence change replaces threonine with isoleucine at codon 599 of the NBN protein (p.Thr599Ile). The threonine residue is weakly conserved and there is a moderate physicochemical difference between threonine and isoleucine. -
Uncertain significance, no assertion criteria provided	clinical testing	Natera, Inc.	Aug 06, 2020	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.13
BayesDel_addAF	Benign	-0.15	T
BayesDel_noAF	Benign	-0.45
CADD	Benign	17
DANN	Uncertain	0.98
DEOGEN2	Benign	0.077	T;T;.
Eigen	Benign	-0.60
Eigen_PC	Benign	-0.48
FATHMM_MKL	Benign	0.067	N
LIST_S2	Benign	0.73	T;T;T
M_CAP	Benign	0.011	T
MetaRNN	Benign	0.066	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.8	L;.;.
MutationTaster	Benign	0.99	N;N
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-1.1	N;N;.
REVEL	Benign	0.036
Sift	Benign	0.14	T;T;.
Sift4G	Benign	0.23	T;T;T
Polyphen		0.022	B;.;.
Vest4		0.10
MutPred		0.18		Loss of glycosylation at T599 (P = 0.0437);.;.;
MVP		0.71
MPC		0.077
ClinPred		0.11	T
GERP RS		3.3
Varity_R		0.038
gMVP		0.099

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: rs775848374; hg19: chr8-90965521;