8-89943252-C-A

Position:

chr8-89943252-C-A

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_ModeratePP3_StrongPP5

The NM_002485.5(NBN):c.2184+1G>T variant causes a splice donor change. The variant allele was found at a frequency of 0.00000434 in 1,613,440 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000034 ( 0 hom. )

Consequence

NBN
NM_002485.5 splice_donor

Scores

Splicing: ADA: 1.000

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:8U:1

Conservation

PhyloP100: 5.21

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 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

PVS1

Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.049889624 fraction of the gene. Cryptic splice site detected, with MaxEntScore 3.7, offset of 11, new splice context is: gaaGTgagg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in inframe change.

PP3

Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

PP5

Variant 8-89943252-C-A is Pathogenic according to our data. Variant chr8-89943252-C-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 233424.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=8, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
NBN	NM_002485.5 linkuse as main transcript	c.2184+1G>T		splice_donor_variant		ENST00000265433.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
NBN	ENST00000265433.8 linkuse as main transcript	c.2184+1G>T		splice_donor_variant		1	NM_002485.5	P1

Frequencies

GnomAD3 genomes

AF:

0.0000132

AC:

AN:

152078

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.00000796

AC:

AN:

251284

Hom.:

AF XY:

0.0000147

AC XY:

AN XY:

135826

show subpopulations

Gnomad AFR exome

AF:

0.000123

Gnomad AMR exome

AF:

0.00

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:

0.00000342

AC:

AN:

1461362

Hom.:

Cov.:

AF XY:

0.00000275

AC XY:

AN XY:

727002

show subpopulations

Gnomad4 AFR exome

AF:

0.000149

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:

0.00

Gnomad4 OTH exome

AF:

0.00

GnomAD4 genome

AF:

0.0000132

AC:

AN:

152078

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74284

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Bravo

AF:

0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:8Uncertain:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

Microcephaly, normal intelligence and immunodeficiency

Pathogenic:5

Likely pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 19, 2024	This sequence change affects a donor splice site in intron 14 of the NBN gene. RNA analysis indicates that disruption of this splice site induces altered splicing and likely results in a shortened protein product. This variant is present in population databases (no rsID available, gnomAD 0.01%). Disruption of this splice site has been observed in individual(s) with breast and/or ovarian cancer (PMID: 28888541, 30130155). ClinVar contains an entry for this variant (Variation ID: 233424). Studies have shown that disruption of this splice site results in skipping of exon 14, but is expected to preserve the integrity of the reading-frame (Invitae). In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Dec 14, 2023	Variant summary: NBN c.2184+1G>T is located in a canonical splice-site and is predicted to affect mRNA splicing resulting in a significantly altered protein due to either exon skipping, shortening, or inclusion of intronic material. Several computational tools predict a significant impact on normal splicing: Four predict the variant abolishes a 5 splicing donor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 1.6e-05 in 256404 control chromosomes (gnomAD and publication data). c.2184+1G>T has been reported in the literature in individuals affected with ovarian cancer, breast cancer or osteosarcoma (Lilyquist_2017, Zheng_2018, Mirabello_2020). These data indicate that the variant may be associated with disease. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 35654374, 29922827, 28888541, 32191290, 30130155). Seven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as likely pathogenic. Based on the evidence outlined above, the variant was classified as likely pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	St. Jude Molecular Pathology, St. Jude Children's Research Hospital	May 27, 2021	The NBN c.2184+1G>T intronic change results from a a G to T substitution at the +1 position of intron 14 of the NBN gene. This variant is predicted to result in loss of the native splice donor site (PP3) and skipping of exon 14 has been confirmed by RNA studies (PVS1_Strong; internal data). This variant has a maximum subpopulation frequency of 0.012% in gnomAD v2.1.1 (PM2_Supporting; https://gnomad.broadinstitute.org/variant/8-90955480-C-A?dataset=gnomad_r2_1). This variant is absent in the FLOSSIES database which contains genetic variants from women older than 70 years of age who have never had cancer (https://whi.color.com/). In summary, this variant meets criteria to be classified as likely pathogenic based on the ACMG/AMP criteria: PVS1_Strong, PM2_Supporting, PP3. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Counsyl	Aug 04, 2016	- -

not provided

Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Mar 01, 2023	Canonical splice site variant reported to result in aberrant splicing (ClinVar SCV000553125.7, SCV001737449.2), disrupting the critical MRE11 interaction domain (Damiola et al., 2014); Not observed at significant frequency in large population cohorts (gnomAD); Observed in individuals with breast or ovarian cancer (Lilyquist et al., 2017; Zheng et al., 2018); This variant is associated with the following publications: (PMID: 29922827, 28888541, 30130155, 24894818) -
Likely pathogenic, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 04, 2019	- -

Hereditary cancer-predisposing syndrome

Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 18, 2023

The c.2184+1G>T intronic variant results from a G to T substitution one nucleotide after coding exon 14 of the NBN gene. One study detected this alteration in 0/3030 pancreatic cancer cases and 2/123136 population controls (Hu C et al. JAMA, 2018 06;319:2401-2409). This alteration was detected in 1/1136 cases and 0/997 controls in a Nigeran breast cancer study (Zheng Y et al. J Clin Oncol, 2018 Oct;36:2820-2825), and was also detected in cohort of 1004 patients with osteosarcoma (Mirabello L et al. JAMA Oncol, 2020 May;6:724-734). This nucleotide position is highly conserved in available vertebrate species. In silico splice site analysis predicts that this alteration will weaken the native splice donor site. RNA studies have demonstrated that this alteration results in abnormal splicing in the set of samples tested (Ambry internal data). Alterations that disrupt the canonical splice site are expected to cause aberrant splicing, resulting in an abnormal protein or a transcript that is subject to nonsense-mediated mRNA decay. As such, this alteration is classified as likely pathogenic. -

Aplastic anemia

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Baylor Genetics

Mar 19, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.45

BayesDel_noAF

Pathogenic

0.43

CADD

Pathogenic

DANN

Uncertain

1.0

Eigen

Pathogenic

1.1

Eigen_PC

Pathogenic

0.98

FATHMM_MKL

Uncertain

0.95

MutationTaster

Benign

1.0

D;D

GERP RS

5.8

RBP_binding_hub_radar

0.0

RBP_regulation_power_radar

1.7

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Pathogenic

1.0

dbscSNV1_RF

Pathogenic

0.94

SpliceAI score (max)

1.0

Details are displayed if max score is > 0.2

DS_DL_spliceai

1.0

Position offset: 1

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

Publications

LitVar

Below is the list of publications found by LitVar. It may be empty.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over