X-48683905-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_000377.3(WAS):c.52G>A(p.Val18Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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 (★). Synonymous variant affecting the same amino acid position (i.e. V18V) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 22)
• Consequence: WAS NM_000377.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.0610

Genes affected

WAS (HGNC:12731): (WASP actin nucleation promoting factor) The Wiskott-Aldrich syndrome (WAS) family of proteins share similar domain structure, and are involved in transduction of signals from receptors on the cell surface to the actin cytoskeleton. The presence of a number of different motifs suggests that they are regulated by a number of different stimuli, and interact with multiple proteins. Recent studies have demonstrated that these proteins, directly or indirectly, associate with the small GTPase, Cdc42, known to regulate formation of actin filaments, and the cytoskeletal organizing complex, Arp2/3. Wiskott-Aldrich syndrome is a rare, inherited, X-linked, recessive disease characterized by immune dysregulation and microthrombocytopenia, and is caused by mutations in the WAS gene. The WAS gene product is a cytoplasmic protein, expressed exclusively in hematopoietic cells, which show signalling and cytoskeletal abnormalities in WAS patients. A transcript variant arising as a result of alternative promoter usage, and containing a different 5' UTR sequence, has been described, however, its full-length nature is not known. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.18600675).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
WAS	NM_000377.3	c.52G>A	p.Val18Ile	missense_variant	1/12	ENST00000376701.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
WAS	ENST00000376701.5	c.52G>A	p.Val18Ile	missense_variant	1/12	1	NM_000377.3	P2

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Wiskott-Aldrich syndrome;C1839163:Thrombocytopenia 1;C1845987:X-linked severe congenital neutropenia Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 24, 2021

This sequence change replaces valine with isoleucine at codon 18 of the WAS protein (p.Val18Ile). The valine residue is weakly conserved and there is a small physicochemical difference between valine and isoleucine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with WAS-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Not Available"; PolyPhen-2: "Benign"; Align-GVGD: "Not Available". The isoleucine 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. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.079
BayesDel_addAF	Benign	-0.035	T
BayesDel_noAF	Benign	-0.29
Cadd	Benign	5.1
Dann	Benign	0.96
DEOGEN2	Benign	0.011	T;T
FATHMM_MKL	Benign	0.23	N
LIST_S2	Benign	0.41	T;T
M_CAP	Pathogenic	0.54	D
MetaRNN	Benign	0.19	T;T
MetaSVM	Pathogenic	0.99	D
MutationTaster	Benign	1.0	N
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-0.42	N;N
REVEL	Uncertain	0.32
Sift	Benign	0.21	T;T
Sift4G	Benign	0.38	T;T
Polyphen		0.0040	.;B
Vest4		0.071
MutPred		0.13		Gain of helix (P = 0.132);Gain of helix (P = 0.132);
MVP		0.79
MPC		0.52
ClinPred		0.026	T
GERP RS		-2.3
Varity_R		0.057
gMVP		0.37

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: rs1569493676; hg19: chrX-48542294;