X-100407579-T-G

Position:

• chrX-100407579-T-G

Variant summary

Our verdict is Pathogenic. Variant got 16 ACMG points: 16P and 0B. PM1 PM2 PP3_Strong PP5_Very_Strong

The NM_001184880.2(PCDH19):​c.1019A>C​(p.Asn340Thr) variant causes a missense 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. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 25)
• Consequence: PCDH19 NM_001184880.2 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 8.02

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]

ACMG classification

Verdict is Pathogenic. Variant got 16 ACMG points.

• PM1: In a domain Cadherin 3 (size 107) in uniprot entity PCD19_HUMAN there are 5 pathogenic changes around while only 0 benign (100%) in NM_001184880.2
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.96
• PP5: Variant X-100407579-T-G is Pathogenic according to our data. Variant chrX-100407579-T-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 429996.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PCDH19	NM_001184880.2	c.1019A>C	p.Asn340Thr	missense_variant	1/6	ENST00000373034.8	NP_001171809.1
PCDH19	NM_001105243.2	c.1019A>C	p.Asn340Thr	missense_variant	1/5		NP_001098713.1
PCDH19	NM_020766.3	c.1019A>C	p.Asn340Thr	missense_variant	1/5		NP_065817.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PCDH19	ENST00000373034.8	c.1019A>C	p.Asn340Thr	missense_variant	1/6	1	NM_001184880.2	ENSP00000362125	A1
PCDH19	ENST00000255531.8	c.1019A>C	p.Asn340Thr	missense_variant	1/5	1		ENSP00000255531	P5
PCDH19	ENST00000420881.6	c.1019A>C	p.Asn340Thr	missense_variant	1/5	1		ENSP00000400327	A1

Frequencies

GnomAD3 genomes Cov.: 25

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 25

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 25, 2018

A variant that is likely pathogenic has been identified in the PCDH19 gene. The N340T variant has not been published as a pathogenic variant, nor has it been reported as a benign variant to our knowledge. A different substitution at the same position (N340S) has been reported previously multiple times in association with PCDH19-related disorders (Depienne et al., 2009; Depienne et al., 2012). The N340T variant is not observed in large population cohorts (Lek et al., 2016; 1000 Genomes Consortium et al., 2015; Exome Variant Server). This substitution occurs at a position that is conserved across species. In silico analysis predicts this variant is probably damaging to the protein structure/function. However, the N340T variant is a conservative amino acid substitution, which is not likely to impact secondary protein structure as these residues share similar properties. Therefore, this variant is likely pathogenic; however, the possibility that it is benign cannot be excluded. -

Developmental and epileptic encephalopathy, 9 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 29, 2022

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant disrupts the p.Asn340 amino acid residue in PCDH19. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19214208, 20713952, 21480887, 21519002). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt PCDH19 protein function. ClinVar contains an entry for this variant (Variation ID: 429996). This variant has not been reported in the literature in individuals affected with PCDH19-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces asparagine, which is neutral and polar, with threonine, which is neutral and polar, at codon 340 of the PCDH19 protein (p.Asn340Thr). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.070
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Uncertain	0.61	.;D;.
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.95	D;D;D
M_CAP	Pathogenic	0.77	D
MetaRNN	Pathogenic	0.96	D;D;D
MetaSVM	Uncertain	0.56	D
MutationAssessor	Pathogenic	3.9	H;H;H
MutationTaster	Benign	1.0	D;D;D
PrimateAI	Uncertain	0.68	T
PROVEAN	Pathogenic	-5.5	D;D;D
REVEL	Pathogenic	0.68
Sift	Uncertain	0.0010	D;D;D
Sift4G	Pathogenic	0.0	D;D;D
Polyphen		1.0, 0.97	.;D;D
Vest4		0.92
MutPred		0.77		Gain of glycosylation at N340 (P = 0.0275);Gain of glycosylation at N340 (P = 0.0275);Gain of glycosylation at N340 (P = 0.0275);
MVP		0.95
MPC		2.0
ClinPred		1.0	D
GERP RS		5.7
Varity_R		0.98
gMVP		0.97

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: rs796052839; hg19: chrX-99662577;