rs267602038

chr8-89981505-G-Achr8-89981505-G-Cchr8-89981505-G-T

Variant summary

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

The NM_002485.5(NBN):c.190C>T(p.Pro64Ser) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,622 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. P64L) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.87

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 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5	c.190C>T	p.Pro64Ser	missense_variant	3/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.190C>T	p.Pro64Ser	missense_variant	3/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251252 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135814

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460622 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726724

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

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

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.00000756

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	May 07, 2023	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 output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The serine amino acid residue is found in multiple mammalian species, which suggests that this missense change does not adversely affect protein function. ClinVar contains an entry for this variant (Variation ID: 77458). This variant has not been reported in the literature in individuals affected with NBN-related conditions. This variant is present in population databases (rs267602038, gnomAD 0.003%). This sequence change replaces proline, which is neutral and non-polar, with serine, which is neutral and polar, at codon 64 of the NBN protein (p.Pro64Ser). -
Uncertain significance, criteria provided, single submitter	clinical testing	Counsyl	Nov 09, 2017	- -

Hereditary cancer-predisposing syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 28, 2019

The p.P64S variant (also known as c.190C>T), located in coding exon 3 of the NBN gene, results from a C to T substitution at nucleotide position 190. The proline at codon 64 is replaced by serine, an amino acid with similar properties. This amino acid position is highly 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 this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.30
BayesDel_addAF	Benign	-0.028	T
BayesDel_noAF	Benign	-0.19
Cadd	Benign	23
Dann	Uncertain	1.0
DEOGEN2	Benign	0.39	T;.
Eigen	Uncertain	0.42
Eigen_PC	Uncertain	0.49
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Uncertain	0.86	D;T
M_CAP	Benign	0.044	D
MetaRNN	Uncertain	0.46	T;T
MetaSVM	Uncertain	-0.080	T
MutationAssessor	Benign	0.86	L;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Benign	0.39	T
PROVEAN	Uncertain	-3.6	D;D
REVEL	Uncertain	0.50
Sift	Benign	0.21	T;T
Sift4G	Benign	0.30	T;T
Polyphen		0.98	D;.
Vest4		0.17
MutPred		0.59		Gain of sheet (P = 0.0101);Gain of sheet (P = 0.0101);
MVP		0.96
MPC		0.15
ClinPred		0.68	D
GERP RS		5.8
Varity_R		0.28
gMVP		0.50

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs267602038; hg19: chr8-90993733; COSMIC: COSV105039095; COSMIC: COSV105039095;