2-15167055-C-CA

Variant names:

• chr2-15167055-C-CA
• NM_015909.4:c.7108dupT

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_Moderate PM2

The NM_015909.4(NBAS):​c.7108dupT​(p.Trp2370LeufsTer12) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (no stars).

• Frequency: Genomes: not found (cov: 33)
• Consequence: NBAS NM_015909.4 frameshift
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 6.88
• Publications: 0 publications found

Genes affected

NBAS (HGNC:15625): (NBAS subunit of NRZ tethering complex) This gene encodes a protein with two leucine zipper domains, a ribosomal protein S14 signature domain and a Sec39 like domain. The protein is thought to be involved in Golgi-to-ER transport. Mutations in this gene are associated with short stature, optic nerve atrophy, and Pelger-Huet anomaly. [provided by RefSeq, Oct 2012]

NBAS Gene-Disease associations (from GenCC):

• infantile liver failure syndrome 2

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), G2P
• short stature-optic atrophy-Pelger-Huët anomaly syndrome

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Illumina, Labcorp Genetics (formerly Invitae), G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.00112 CDS is truncated, and there are 0 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
NBAS	NM_015909.4	c.7108dupT	p.Trp2370LeufsTer12	frameshift_variant	Exon 52 of 52	ENST00000281513.10	NP_056993.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
NBAS	ENST00000281513.10	c.7108dupT	p.Trp2370LeufsTer12	frameshift_variant	Exon 52 of 52	1	NM_015909.4	ENSP00000281513.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

NBAS-related disorder Uncertain:1

Jul 18, 2024

PreventionGenetics, part of Exact Sciences

Significance: Uncertain significance

Review Status: no assertion criteria provided

Collection Method: clinical testing

The NBAS c.7108dupT variant is predicted to result in a frameshift and premature protein termination (p.Trp2370Leufs*12). To our knowledge, this variant has not been reported in the literature or in a large population database, indicating this variant is rare. While frameshift variants are a known mechanism of disease, this frameshift variant is located in the terminal exon and therefore the transcript is not expected to undergo nonsense mediated decay, and no loss of function variants have been reported downstream of this variant. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		6.9

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

Other links and lift over

hg19: chr2-15307179;