8-89984563-G-T

Position:

• chr8-89984563-G-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_Strong BP6

The NM_002485.5(NBN):​c.-2C>A variant causes a 5 prime UTR change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000992 in 1,612,992 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000053 (1 hom., cov: 33)
  • Exomes 𝑓: 0.0000055 (0 hom.)
• Consequence: NBN NM_002485.5 5_prime_UTR
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:2
• Conservation: PhyloP100: 0.356

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 (HGNC:):

ACMG classification

Verdict is Likely_benign. Variant got -5 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.68).
• BP6: Variant 8-89984563-G-T is Benign according to our data. Variant chr8-89984563-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 142021.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=5}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
NBN	NM_002485.5	c.-2C>A		5_prime_UTR_variant	1/16	ENST00000265433.8	NP_002476.2
NBN	NM_001024688.3	c.-298C>A		5_prime_UTR_variant	1/17		NP_001019859.1
NBN	XM_011517046.2	c.-2C>A		5_prime_UTR_variant	1/11		XP_011515348.1
NBN	XM_047421796.1	c.-2C>A		5_prime_UTR_variant	1/10		XP_047277752.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
NBN	ENST00000265433.8	c.-2C>A		5_prime_UTR_variant	1/16	1	NM_002485.5	ENSP00000265433.4

Frequencies

GnomAD3 genomes AF: 0.0000525 AC: 8 AN: 152252 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000523

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: 0.0000123 AC: 3 AN: 244888 Hom.: 0 AF XY: 0.0000149 AC XY: 2 AN XY: 133794

Gnomad AFR exome AF: 0.00

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: 0.0000475

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000334

GnomAD4 exome AF: 0.00000548 AC: 8 AN: 1460740 Hom.: 0 Cov.: 30 AF XY: 0.00000413 AC XY: 3 AN XY: 726738

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: 0.00

Gnomad4 OTH exome AF: 0.000133

GnomAD4 genome AF: 0.0000525 AC: 8 AN: 152252 Hom.: 1 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74380

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000523

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: 0.0000189

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Feb 26, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 24, 2020	Variant summary: NBN c.-2C>A is located in the untranslated mRNA region upstream of the initiation codon. The variant allele was found at a frequency of 1.2e-05 in 244888 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.-2C>A has been reported in the literature in at-least one individual undergoing clinical genetic testing based on a history of Lynch syndrome-associated cancer and/or polyps (Yurgelun_2015). This report does not provide unequivocal conclusions about association of the variant with Nijmegen Breakage Syndrome and/or NBN related cancer predisposition syndrome. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments and limited evidence (VUS, n=2, likely benign, n=2). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Microcephaly, normal intelligence and immunodeficiency Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 20, 2024	This variant occurs in a non-coding region of the NBN gene. It does not change the encoded amino acid sequence of the NBN protein. This variant is present in population databases (rs202104448, gnomAD 0.0009%). 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: 142021). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	Genome-Nilou Lab	Nov 07, 2021	- -

not provided Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Quest Diagnostics Nichols Institute San Juan Capistrano	Nov 04, 2019	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 10, 2019	This variant is associated with the following publications: (PMID: 25980754, 24168161) -

Hereditary cancer-predisposing syndrome Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 23, 2019

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.68
CADD	Benign	11
DANN	Benign	0.83
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.0

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

LitVar

Other links and lift over

dbSNP: rs202104448; hg19: chr8-90996791;