rs1554564219

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_002485.5(NBN):​c.677C>T​(p.Thr226Ile) variant causes a missense change. The variant allele was found at a frequency of 0.000000685 in 1,460,614 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. T226A) 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

Scores

3
11
5

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 3.77

Publications

0 publications found
Variant links:
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]
NBN Gene-Disease associations (from GenCC):
  • Nijmegen breakage syndrome
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Myriad Women’s Health
  • rhabdomyosarcoma
    Inheritance: AR Classification: MODERATE Submitted by: Genomics England PanelApp
  • idiopathic aplastic anemia
    Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)
  • prostate cancer
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
  • hereditary breast carcinoma
    Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 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
NBNNM_002485.5 linkc.677C>T p.Thr226Ile missense_variant Exon 6 of 16 ENST00000265433.8 NP_002476.2 O60934

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
NBNENST00000265433.8 linkc.677C>T p.Thr226Ile missense_variant Exon 6 of 16 1 NM_002485.5 ENSP00000265433.4 O60934

Frequencies

GnomAD3 genomes
Cov.:
32
GnomAD4 exome
AF:
6.85e-7
AC:
1
AN:
1460614
Hom.:
0
Cov.:
30
AF XY:
0.00000138
AC XY:
1
AN XY:
726598
show subpopulations
⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
33416
American (AMR)
AF:
0.00
AC:
0
AN:
44644
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26102
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39574
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86226
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53280
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5756
European-Non Finnish (NFE)
AF:
9.00e-7
AC:
1
AN:
1111310
Other (OTH)
AF:
0.00
AC:
0
AN:
60306
⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.325
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
Cov.:
32

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:4
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency Uncertain:3
Sep 16, 2021
Natera, Inc.
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Nov 07, 2021
Genome-Nilou Lab
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 25, 2023
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This sequence change replaces threonine, which is neutral and polar, with isoleucine, which is neutral and non-polar, at codon 226 of the NBN protein (p.Thr226Ile). This variant is not present in population databases (gnomAD 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: 490060). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be disruptive. 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. -

Hereditary cancer-predisposing syndrome Uncertain:1
May 02, 2019
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.T226I variant (also known as c.677C>T), located in coding exon 6 of the NBN gene, results from a C to T substitution at nucleotide position 677. The threonine at codon 226 is replaced by isoleucine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious 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
0.14
BayesDel_addAF
Pathogenic
0.29
D
BayesDel_noAF
Pathogenic
0.17
CADD
Benign
23
DANN
Uncertain
1.0
DEOGEN2
Benign
0.40
T;T;.;.
Eigen
Uncertain
0.62
Eigen_PC
Uncertain
0.59
FATHMM_MKL
Uncertain
0.88
D
LIST_S2
Benign
0.85
T;T;D;D
M_CAP
Benign
0.078
D
MetaRNN
Uncertain
0.60
D;D;D;D
MetaSVM
Uncertain
0.070
D
MutationAssessor
Pathogenic
2.9
M;.;.;.
PhyloP100
3.8
PrimateAI
Uncertain
0.65
T
PROVEAN
Uncertain
-3.9
D;D;D;D
REVEL
Uncertain
0.56
Sift
Uncertain
0.013
D;D;D;D
Sift4G
Uncertain
0.038
D;D;T;.
Polyphen
1.0
D;.;.;.
Vest4
0.53
MVP
0.95
MPC
0.29
ClinPred
0.99
D
GERP RS
5.0
Varity_R
0.20
gMVP
0.75
Mutation Taster
=75/25
polymorphism

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

Other links and lift over

dbSNP: rs1554564219; hg19: chr8-90983426; COSMIC: COSV108098413; API