rs863224715

chr8-89970406-C-G

Variant summary

Our verdict is Likely benign. Variant got -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP6

The NM_002485.5(NBN):c.854G>C(p.Cys285Ser) 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. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. C285F) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:1
• 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 Likely_benign. Variant got -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.028358102).
• BP6: Variant 8-89970406-C-G is Benign according to our data. Variant chr8-89970406-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 216569.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=1, Uncertain_significance=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5	c.854G>C	p.Cys285Ser	missense_variant	7/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.854G>C	p.Cys285Ser	missense_variant	7/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Aug 31, 2021	This sequence change replaces cysteine with serine at codon 285 of the NBN protein (p.Cys285Ser). The cysteine residue is weakly conserved and there is a moderate physicochemical difference between cysteine and serine. 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: 216569). Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 10, 2019

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.046
BayesDel_addAF	Benign	-0.31	T
BayesDel_noAF	Benign	-0.68
Cadd	Benign	17
Dann	Benign	0.21
DEOGEN2	Benign	0.065	T;T
Eigen	Benign	-0.90
Eigen_PC	Benign	-0.57
FATHMM_MKL	Benign	0.019	N
LIST_S2	Benign	0.46	T;T
M_CAP	Benign	0.0035	T
MetaRNN	Benign	0.028	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	-2.9	N;.
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.32	T
PROVEAN	Benign	2.7	N;N
REVEL	Benign	0.13
Sift	Benign	1.0	T;T
Sift4G	Benign	1.0	T;T
Polyphen		0.0	B;.
Vest4		0.078
MutPred		0.46		Gain of disorder (P = 0.0016);.;
MVP		0.35
MPC		0.081
ClinPred		0.12	T
GERP RS		4.7
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.068
gMVP		0.31

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: rs863224715; hg19: chr8-90982634;