rs1131691608

Variant names:

• chrX-41346503-A-G
• rs1131691608
• NM_001356.5:c.1498-2A>G

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001356.5(DDX3X):​c.1498-2A>G variant causes a splice acceptor, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 2/2 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★★).

• Frequency: Genomes: not found (cov: 22)
• Consequence: DDX3X NM_001356.5 splice_acceptor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.27
• Publications: 0 publications found

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]

DDX3X Gene-Disease associations (from GenCC):

• intellectual disability, X-linked 102

  Inheritance: XL Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• X-linked syndromic intellectual disability

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen, Illumina
• Toriello-Carey syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• X-linked intellectual disability-hypotonia-movement disorder syndrome

  Inheritance: XL Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, Cryptic splice site detected, with MaxEntScore 4.7, offset of -31, new splice context is: agtatttgttttcttttaAGtgg. Cryptic site results in frameshift change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-41346503-A-G is Pathogenic according to our data. Variant chrX-41346503-A-G is described in ClinVar as Pathogenic. ClinVar VariationId is 429815.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DDX3X	NM_001356.5	c.1498-2A>G		splice_acceptor_variant, intron_variant	Intron 13 of 16	ENST00000644876.2	NP_001347.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DDX3X	ENST00000644876.2	c.1498-2A>G		splice_acceptor_variant, intron_variant	Intron 13 of 16		NM_001356.5	ENSP00000494040.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome Cov.: 29

GnomAD4 genome Cov.: 22

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Inborn genetic diseases Pathogenic:1

Jul 30, 2015

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Pathogenic:1

Sep 14, 2015

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1498-2A>G variant in the DDX3X gene has not been reported previously as a pathogenic variant nor as a benign polymorphism, to our knowledge. This splice site variant destroys the canonical splice acceptor site in intron 13. It is predicted to cause abnormal gene splicing, either leading to an abnormal message that is subject to nonsense-mediated mRNA decay, or to an abnormal protein product if the message is used for protein translation. The c.1498-2A>G variant was not observed in approximately 6500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. We interpret c.1498-2A>G as a pathogenic variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.25
BayesDel_addAF	Pathogenic	0.73	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	32
DANN	Uncertain	0.99
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.3
GERP RS		5.2
PromoterAI		0.086	Neutral
Mutation Taster		=0/100	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.72		Position offset: 9
DS_AL_spliceai		0.99		Position offset: 2

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

Other links and lift over

dbSNP: rs1131691608; hg19: chrX-41205756; COSMIC: COSV106114753; COSMIC: COSV106114753;