8-89978263-G-T

Position:

• chr8-89978263-G-T

Variant summary

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

The NM_002485.5(NBN):​c.541C>A​(p.Leu181Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000207 in 1,452,274 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 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. L181L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.888

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=0.15807468).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5	c.541C>A	p.Leu181Met	missense_variant	5/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.541C>A	p.Leu181Met	missense_variant	5/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000207 AC: 3 AN: 1452274 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 723204

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: 0.00000272

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 09, 2017

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. 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. 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 leucine with methionine at codon 181 of the NBN protein (p.Leu181Met). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and methionine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	21
DANN	Uncertain	0.97
DEOGEN2	Benign	0.22	T;T;.
Eigen	Benign	-0.19
Eigen_PC	Benign	-0.15
FATHMM_MKL	Benign	0.51	D
LIST_S2	Benign	0.63	T;T;T
M_CAP	Benign	0.010	T
MetaRNN	Benign	0.16	T;T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.9	L;.;.
MutationTaster	Benign	0.72	N;N
PrimateAI	Benign	0.37	T
PROVEAN	Benign	-0.90	N;N;N
REVEL	Benign	0.065
Sift	Benign	0.12	T;T;T
Sift4G	Benign	0.19	T;T;.
Polyphen		0.55	P;.;.
Vest4		0.33
MutPred		0.57		Loss of methylation at K182 (P = 0.0384);.;.;
MVP		0.70
MPC		0.13
ClinPred		0.20	T
GERP RS		0.51
Varity_R		0.17
gMVP		0.36

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: rs1060504930; hg19: chr8-90990491; COSMIC: COSV55375607; COSMIC: COSV55375607;