chrX-41334258-T-TC

Variant names:

• chrX-41334258-T-TC
• NM_001356.5:c.7dupC

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_001356.5(DDX3X):​c.7dupC​(p.His3ProfsTer24) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 24)
• Consequence: DDX3X NM_001356.5 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 6.61

Genes affected

DDX3X (HGNC:2745): (DEAD-box helicase 3 X-linked) The protein encoded by this gene is a member of the large DEAD-box protein family, that is defined by the presence of the conserved Asp-Glu-Ala-Asp (DEAD) motif, and has ATP-dependent RNA helicase activity. This protein has been reported to display a high level of RNA-independent ATPase activity, and unlike most DEAD-box helicases, the ATPase activity is thought to be stimulated by both RNA and DNA. This protein has multiple conserved domains and is thought to play roles in both the nucleus and cytoplasm. Nuclear roles include transcriptional regulation, mRNP assembly, pre-mRNA splicing, and mRNA export. In the cytoplasm, this protein is thought to be involved in translation, cellular signaling, and viral replication. Misregulation of this gene has been implicated in tumorigenesis. This gene has a paralog located in the nonrecombining region of the Y chromosome. Pseudogenes sharing similarity to both this gene and the DDX3Y paralog are found on chromosome 4 and the X chromosome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Oct 2014]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 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 7 pathogenic variants in the truncated region.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-41334258-T-TC is Pathogenic according to our data. Variant chrX-41334258-T-TC is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2584424.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DDX3X	NM_001356.5	c.7dupC	p.His3ProfsTer24	frameshift_variant	Exon 1 of 17	ENST00000644876.2	NP_001347.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DDX3X	ENST00000644876.2	c.7dupC	p.His3ProfsTer24	frameshift_variant	Exon 1 of 17		NM_001356.5	ENSP00000494040.1

Frequencies

GnomAD3 genomes Cov.: 24

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 24

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

DDX3X-Related Neurodevelopmental Disorder Pathogenic:1

-

Rady Children's Institute for Genomic Medicine, Rady Children's Hospital San Diego

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This frameshifting variant in exon 1 of 17 introduces a premature stop codon and is therefore predicted to result in loss of normal protein function through either protein truncation or nonsense-mediated mRNA decay (NMD). This variant has not been previously reported or functionally characterized in the literature to our knowledge. Loss-of-function variation in DDX3X is an established mechanism of disease (PMID: 26235985). The c.7dup (p.His3ProfsTer24) variant is absent from the gnomAD population database and thus is presumed to be rare. Based on the available evidence, the c.7dup (p.His3ProfsTer24) variant is classified as Likely Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chrX-41193511;