8-89937072-G-T

Variant names:

• chr8-89937072-G-T
• NM_002485.5:c.2188C>A

Variant summary

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

The NM_002485.5(NBN):​c.2188C>A​(p.Gln730Lys) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,459,796 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.31

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 rank	MANE	Protein	UniProt
NBN	NM_002485.5	c.2188C>A	p.Gln730Lys	missense_variant	Exon 15 of 16	ENST00000265433.8	NP_002476.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.2188C>A	p.Gln730Lys	missense_variant	Exon 15 of 16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459796 Hom.: 0 Cov.: 29 AF XY: 0.00000138 AC XY: 1 AN XY: 726252

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:1

Jul 17, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is not present in population databases (ExAC no frequency). This sequence change replaces glutamine with lysine at codon 730 of the NBN protein (p.Gln730Lys). The glutamine residue is moderately conserved and there is a small physicochemical difference between glutamine and lysine. 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 sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with NBN-related conditions. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.26
BayesDel_addAF	Uncertain	0.014	T
BayesDel_noAF	Benign	-0.22
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Benign	0.26	T;T;.
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.28
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.85	D;T;T
M_CAP	Benign	0.058	D
MetaRNN	Uncertain	0.67	D;D;D
MetaSVM	Benign	-0.37	T
MutationAssessor	Uncertain	2.3	M;.;.
PrimateAI	Uncertain	0.50	T
PROVEAN	Benign	-1.9	N;N;.
REVEL	Uncertain	0.36
Sift	Uncertain	0.0050	D;D;.
Sift4G	Uncertain	0.017	D;D;D
Polyphen		1.0	D;.;.
Vest4		0.73
MutPred		0.68		Gain of ubiquitination at Q730 (P = 0.0069);.;.;
MVP		0.81
MPC		0.45
ClinPred		0.95	D
GERP RS		4.5
Varity_R		0.42
gMVP		0.45

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.10		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr8-90949300;