1-1014053-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_005101.4(ISG15):c.73G>T(p.Val25Leu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,410 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/23 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ISG15 NM_005101.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: -2.56

Genes affected

ISG15 (HGNC:4053): (ISG15 ubiquitin like modifier) The protein encoded by this gene is a ubiquitin-like protein that is conjugated to intracellular target proteins upon activation by interferon-alpha and interferon-beta. Several functions have been ascribed to the encoded protein, including chemotactic activity towards neutrophils, direction of ligated target proteins to intermediate filaments, cell-to-cell signaling, and antiviral activity during viral infections. While conjugates of this protein have been found to be noncovalently attached to intermediate filaments, this protein is sometimes secreted. [provided by RefSeq, Dec 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ISG15	NM_005101.4	c.73G>T	p.Val25Leu	missense_variant	2/2	ENST00000649529.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ISG15	ENST00000649529.1	c.73G>T	p.Val25Leu	missense_variant	2/2		NM_005101.4	P1
ISG15	ENST00000624697.4	c.49G>T	p.Val17Leu	missense_variant	3/3	3
ISG15	ENST00000624652.1	c.49G>T	p.Val17Leu	missense_variant	3/3	3

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460410 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726278

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: 9.00e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 35

ExAC AF: 0.00000824 AC: 1

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Mendelian susceptibility to mycobacterial diseases due to complete ISG15 deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Oct 10, 2020

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. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Benign"; Align-GVGD: "Class C0". The leucine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies and their clinical significance is uncertain. This variant has not been reported in the literature in individuals with ISG15-related conditions. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the ExAC database. This sequence change replaces valine with leucine at codon 25 of the ISG15 protein (p.Val25Leu). The valine residue is moderately conserved and there is a small physicochemical difference between valine and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Benign	-0.19	T
BayesDel_noAF	Benign	-0.51
Cadd	Benign	0.075
Dann	Benign	0.76
DEOGEN2	Benign	0.031	T;T;T;T
Eigen	Benign	-1.4
Eigen_PC	Benign	-1.6
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.57	T;T;.;T
M_CAP	Uncertain	0.19	D
MetaRNN	Benign	0.29	T;T;T;T
MetaSVM	Benign	-0.67	T
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.35	T
Sift4G	Benign	0.092	T;T;T;.
Polyphen		0.011	.;.;B;B
Vest4		0.072
MutPred		0.71		.;.;Loss of catalytic residue at V25 (P = 0.0056);Loss of catalytic residue at V25 (P = 0.0056);
MVP		0.12
MPC		0.20
ClinPred		0.21	T
GERP RS		-7.8
Varity_R		0.25
gMVP		0.69

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.39		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.39		Position offset: 7

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

Publications

LitVar

Other links and lift over

dbSNP: rs775288454; hg19: chr1-949433;