chr22-18170769-A-G

Position:

• chr22-18170769-A-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_017414.4(USP18):​c.740A>G​(p.His247Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000411 in 1,461,396 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 21)
  • Exomes 𝑓: 0.0000041 (0 hom.)
• Consequence: USP18 NM_017414.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.273

Genes affected

USP18 (HGNC:12616): (ubiquitin specific peptidase 18) The protein encoded by this gene belongs to the ubiquitin-specific proteases (UBP) family of enzymes that cleave ubiquitin from ubiquitinated protein substrates. It is highly expressed in liver and thymus, and is localized to the nucleus. This protein efficiently cleaves only ISG15 (a ubiquitin-like protein) fusions, and deletion of this gene in mice results in a massive increase of ISG15 conjugates in tissues, indicating that this protein is a major ISG15-specific protease. Mice lacking this gene are also hypersensitive to interferon, suggesting a function of this protein in downregulating interferon responses, independent of its isopeptidase activity towards ISG15. [provided by RefSeq, Sep 2011]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.060551047).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
USP18	NM_017414.4	c.740A>G	p.His247Arg	missense_variant	8/11	ENST00000215794.8
USP18	XM_006724074.4	c.518A>G	p.His173Arg	missense_variant	7/10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
USP18	ENST00000215794.8	c.740A>G	p.His247Arg	missense_variant	8/11	1	NM_017414.4	P1
USP18	ENST00000699060.1	c.723+830A>G		intron_variant
USP18	ENST00000699061.1	n.486A>G		non_coding_transcript_exon_variant	5/6

Frequencies

GnomAD3 genomes Cov.: 21

GnomAD4 exome AF: 0.00000411 AC: 6 AN: 1461396 Hom.: 0 Cov.: 31 AF XY: 0.00000413 AC XY: 3 AN XY: 727030

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: 0.00000540

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 21

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 23, 2024

The c.740A>G (p.H247R) alteration is located in exon 8 (coding exon 7) of the USP18 gene. This alteration results from a A to G substitution at nucleotide position 740, causing the histidine (H) at amino acid position 247 to be replaced by an arginine (R). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.078
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.63
CADD	Benign	12
DANN	Benign	0.72
DEOGEN2	Benign	0.20	T
Eigen	Benign	-0.99
Eigen_PC	Benign	-0.94
FATHMM_MKL	Benign	0.013	N
LIST_S2	Benign	0.64	T
M_CAP	Benign	0.0077	T
MetaRNN	Benign	0.061	T
MetaSVM	Benign	-1.0	T
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.29	T
PROVEAN	Uncertain	-2.6	D
REVEL	Benign	0.034
Sift	Benign	0.23	T
Sift4G	Benign	0.13	T
Polyphen		0.0070	B
Vest4		0.15
MutPred		0.26		Gain of MoRF binding (P = 0.0066);
MVP		0.15
MPC		2.3
ClinPred		0.15	T
GERP RS		-0.90
Varity_R		0.10
gMVP		0.21

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: rs1929607392; hg19: chr22-18653536;