chr16-58001543-CG-C

Variant names:

• chr16-58001543-CG-C
• rs747958554
• NM_024598.4:c.63delG

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PVS1_Strong PM2 PP5_Very_Strong

The NM_024598.4(USB1):​c.63delG​(p.Met22CysfsTer29) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000317 in 1,609,456 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000034 (0 hom.)
• Consequence: USB1 NM_024598.4 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: -0.0670

Genes affected

USB1 (HGNC:25792): (U6 snRNA biogenesis phosphodiesterase 1) This gene encodes a protein with several conserved domains, however, its exact function is not known. Mutations in this gene are associated with poikiloderma with neutropenia (PN), which shows phenotypic overlap with Rothmund-Thomson syndrome (RTS) caused by mutations in the RECQL4 gene. It is believed that this gene product interacts with RECQL4 protein via SMAD4 proteins, explaining the partial clinical overlap between PN and RTS. Alternatively spliced transcript variants encoding different isoforms have been noted for this gene. [provided by RefSeq, Mar 2011]

ACMG classification

Verdict is Pathogenic. Variant got 14 ACMG points.

• PVS1: Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 11 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 16-58001543-CG-C is Pathogenic according to our data. Variant chr16-58001543-CG-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1071879.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
USB1	NM_024598.4	c.63delG	p.Met22CysfsTer29	frameshift_variant	Exon 1 of 7	ENST00000219281.8	NP_078874.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
USB1	ENST00000219281.8	c.63delG	p.Met22CysfsTer29	frameshift_variant	Exon 1 of 7	1	NM_024598.4	ENSP00000219281.3

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152150 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000127 AC: 3 AN: 236236 Hom.: 0 AF XY: 0.0000232 AC XY: 3 AN XY: 129156

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: 0.00

Gnomad NFE exome AF: 0.0000285

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000336 AC: 49 AN: 1457306 Hom.: 0 Cov.: 32 AF XY: 0.0000290 AC XY: 21 AN XY: 724574

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: 0.0000432

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152150 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74326

Gnomad4 AFR AF: 0.00

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: 0.0000294

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000434 Hom.: 0

Bravo AF: 0.0000113

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Poikiloderma with neutropenia Pathogenic:1

Apr 29, 2022

Fulgent Genetics, Fulgent Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Sep 19, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Met22Cysfs*29) in the USB1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in USB1 are known to be pathogenic (PMID: 20817924, 25044170). This variant is present in population databases (rs747958554, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with USB1-related conditions. ClinVar contains an entry for this variant (Variation ID: 1071879). For these reasons, this variant has been classified as Pathogenic. -

USB1-related disorder Pathogenic:1

Mar 21, 2024

PreventionGenetics, part of Exact Sciences

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

The USB1 c.63delG variant is predicted to result in a frameshift and premature protein termination (p.Met22Cysfs*29). To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0029% of alleles in individuals of European (Non-Finnish) descent in gnomAD and interpreted as likely pathogenic or pathogenic in ClinVar (https://www.ncbi.nlm.nih.gov/clinvar/variation/1071879/). Frameshift variants in USB1 are expected to be pathogenic. This variant is interpreted as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

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: rs747958554; hg19: chr16-58035447;