8-89981505-G-C

Variant summary

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

The NM_002485.5(NBN):c.190C>G(p.Pro64Ala) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. 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)
• Consequence: NBN NM_002485.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• 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>G	p.Pro64Ala	missense_variant	3/16	ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8	c.190C>G	p.Pro64Ala	missense_variant	3/16	1	NM_002485.5	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

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

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 20, 2021

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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals with NBN-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces proline with alanine at codon 64 of the NBN protein (p.Pro64Ala). The proline residue is weakly conserved and there is a small physicochemical difference between proline and alanine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.16
BayesDel_addAF	Uncertain	0.10	D
BayesDel_noAF	Benign	-0.090
Cadd	Uncertain	24
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.52	D;.
Eigen	Uncertain	0.67
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.89	D
LIST_S2	Benign	0.84	T;T
M_CAP	Benign	0.070	D
MetaRNN	Uncertain	0.74	D;D
MetaSVM	Uncertain	0.52	D
MutationAssessor	Uncertain	2.0	M;.
MutationTaster	Benign	0.99	D;D
PrimateAI	Benign	0.38	T
PROVEAN	Uncertain	-4.1	D;D
REVEL	Uncertain	0.56
Sift	Uncertain	0.015	D;T
Sift4G	Uncertain	0.056	T;T
Polyphen		1.0	D;.
Vest4		0.44
MutPred		0.64		Gain of sheet (P = 0.0101);Gain of sheet (P = 0.0101);
MVP		0.97
MPC		0.29
ClinPred		0.99	D
GERP RS		5.8
Varity_R		0.28
gMVP		0.44

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: chr8-90993733;