chrX-100402686-CT-C

Variant names:

• chrX-100402686-CT-C
• rs1555984453
• NM_001184880.2:c.2453delA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_001184880.2(PCDH19):​c.2453delA​(p.Gln818ArgfsTer16) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 23)
• Consequence: PCDH19 NM_001184880.2 frameshift
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 4.50
• Publications: 0 publications found

Genes affected

PCDH19 (HGNC:14270): (protocadherin 19) The protein encoded by this gene is a member of the delta-2 protocadherin subclass of the cadherin superfamily. The encoded protein is thought to be a calcium-dependent cell-adhesion protein that is primarily expressed in the brain. Mutations in this gene on human chromosome X are associated with sporadic infantile epileptic encephalopathy and to a female-restricted form of epilepsy (EFMR; also known as PCDH19RE). Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2017]

PCDH19 Gene-Disease associations (from GenCC):

• developmental and epileptic encephalopathy, 9

  Inheritance: XL, Unknown Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Orphanet, Labcorp Genetics (formerly Invitae), Ambry Genetics
• X-linked complex neurodevelopmental disorder

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• Dravet syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Pathogenic. The variant received 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant X-100402686-CT-C is Pathogenic according to our data. Variant chrX-100402686-CT-C is described in ClinVar as Pathogenic. ClinVar VariationId is 465300.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001184880.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PCDH19	NM_001184880.2	MANE Select	c.2453delA	p.Gln818ArgfsTer16	frameshift	Exon 3 of 6	NP_001171809.1
	PCDH19	NM_001105243.2		c.2312delA	p.Gln771ArgfsTer16	frameshift	Exon 2 of 5	NP_001098713.1
	PCDH19	NM_020766.3		c.2312delA	p.Gln771ArgfsTer16	frameshift	Exon 2 of 5	NP_065817.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	PCDH19	ENST00000373034.8	TSL:1 MANE Select	c.2453delA	p.Gln818ArgfsTer16	frameshift	Exon 3 of 6	ENSP00000362125.4
	PCDH19	ENST00000255531.8	TSL:1	c.2312delA	p.Gln771ArgfsTer16	frameshift	Exon 2 of 5	ENSP00000255531.7
	PCDH19	ENST00000420881.6	TSL:1	c.2312delA	p.Gln771ArgfsTer16	frameshift	Exon 2 of 5	ENSP00000400327.2

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Developmental and epileptic encephalopathy, 9 Pathogenic:1

Nov 12, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln818Argfs*16) in the PCDH19 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PCDH19 are known to be pathogenic (PMID: 21053371). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with PCDH19-related conditions. ClinVar contains an entry for this variant (Variation ID: 465300). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		4.5
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.16		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1555984453; hg19: chrX-99657684;