chr20-34408687-G-T

Position:

• chr20-34408687-G-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_031483.7(ITCH):​c.107G>T​(p.Trp36Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,494 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: ITCH NM_031483.7 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.56

Genes affected

ITCH (HGNC:13890): (itchy E3 ubiquitin protein ligase) This gene encodes a member of the Nedd4 family of HECT domain E3 ubiquitin ligases. HECT domain E3 ubiquitin ligases transfer ubiquitin from E2 ubiquitin-conjugating enzymes to protein substrates, thus targeting specific proteins for lysosomal degradation. The encoded protein plays a role in multiple cellular processes including erythroid and lymphoid cell differentiation and the regulation of immune responses. Mutations in this gene are a cause of syndromic multisystem autoimmune disease. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, Mar 2012]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), ITCH. . Gene score misZ 3.5832 (greater than the threshold 3.09). Trascript score misZ 4.3516 (greater than threshold 3.09). GenCC has associacion of gene with syndromic multisystem autoimmune disease due to ITCH deficiency.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
ITCH	NM_031483.7	c.107G>T	p.Trp36Leu	missense_variant	4/25	ENST00000374864.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
ITCH	ENST00000374864.10	c.107G>T	p.Trp36Leu	missense_variant	4/25	1	NM_031483.7	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461494 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 727084

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.0000383

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: 0.00

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000936 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Syndromic multisystem autoimmune disease due to ITCH deficiency Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 14, 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 are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Not Available"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Not Available"). This variant has not been reported in the literature in individuals with ITCH-related conditions. This variant is not present in population databases (ExAC no frequency). This sequence change replaces tryptophan with leucine at codon 36 of the ITCH protein (p.Trp36Leu). The tryptophan residue is moderately conserved and there is a small physicochemical difference between tryptophan and leucine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.48
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	29
DANN	Uncertain	0.99
DEOGEN2	Benign	0.41	.;.;T
Eigen	Uncertain	0.53
Eigen_PC	Uncertain	0.62
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.90	D;D;D
M_CAP	Benign	0.036	D
MetaRNN	Uncertain	0.71	D;D;D
MetaSVM	Benign	-0.50	T
MutationAssessor	Benign	1.6	L;.;L
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Pathogenic	0.85	D
PROVEAN	Uncertain	-3.4	D;.;D
REVEL	Uncertain	0.62
Sift	Benign	0.39	T;.;T
Sift4G	Benign	0.47	T;.;T
Polyphen		1.0	.;.;D
Vest4		0.75
MutPred		0.53		Loss of catalytic residue at P39 (P = 0.0267);Loss of catalytic residue at P39 (P = 0.0267);Loss of catalytic residue at P39 (P = 0.0267);
MVP		0.93
MPC		0.84
ClinPred		0.96	D
GERP RS		5.3
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.61
gMVP		0.61

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: rs1978501760; hg19: chr20-32996493;