X-18507154-G-C

Variant names:

• chrX-18507154-G-C
• rs267608418
• NM_001323289.2:c.58G>C

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Very_Strong

The NM_001323289.2(CDKL5):​c.58G>C​(p.Gly20Arg) 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. 13/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G20V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 23)
• Consequence: CDKL5 NM_001323289.2 missense
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 8.37
• Publications: 4 publications found

Genes affected

CDKL5 (HGNC:11411): (cyclin dependent kinase like 5) This gene is a member of Ser/Thr protein kinase family and encodes a phosphorylated protein with protein kinase activity. Mutations in this gene have been associated with X-linked infantile spasm syndrome (ISSX), also known as X-linked West syndrome, and Rett syndrome (RTT). Alternate transcriptional splice variants have been characterized. [provided by RefSeq, Jul 2008]

CDKL5 Gene-Disease associations (from GenCC):

• CDKL5 disorder

  Inheritance: XL Classification: DEFINITIVE Submitted by: ClinGen
• developmental and epileptic encephalopathy, 2

  Inheritance: XL Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• atypical Rett syndrome

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• genetic developmental and epileptic encephalopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• infantile spasms

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• precocious puberty

  Inheritance: XL Classification: LIMITED Submitted by: Ambry Genetics

ACMG classification

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

• PM1: In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_001323289.2
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chrX-18507155-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 918032.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.991
• PP5: Variant X-18507154-G-C is Pathogenic according to our data. Variant chrX-18507154-G-C is described in ClinVar as Pathogenic. ClinVar VariationId is 143828.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
CDKL5	NM_001323289.2	c.58G>C	p.Gly20Arg	missense_variant	Exon 2 of 18	ENST00000623535.2	NP_001310218.1
CDKL5	NM_001037343.2	c.58G>C	p.Gly20Arg	missense_variant	Exon 3 of 22		NP_001032420.1
CDKL5	NM_003159.3	c.58G>C	p.Gly20Arg	missense_variant	Exon 2 of 21		NP_003150.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKL5	ENST00000623535.2	c.58G>C	p.Gly20Arg	missense_variant	Exon 2 of 18	1	NM_001323289.2	ENSP00000485244.1

Frequencies

GnomAD3 genomes Cov.: 23

GnomAD4 exome Cov.: 25

GnomAD4 genome Cov.: 23

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Developmental and epileptic encephalopathy, 2 Pathogenic:1

Mar 13, 2014

RettBASE

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: curation

In silico prediction: SIFT = deleterious, MutationTaster = disease-causing, PolyPhen2 = probably damaging, AlignGVGD = benign (C0)

CDKL5 disorder Pathogenic:1

Aug 21, 2024

Centre for Population Genomics, CPG

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: curation

This variant has been collected from RettBASE and curated to current modified ACMG/AMP criteria. Based on the classification scheme defined by the ClinGen Rett/Angelman-like Expert Panel for Rett/AS-like Disorders Specifications to the ACMG/AMP Variant Interpretation Guidelines VCEP 3.0, this variant is classified as pathogenic. At least the following criteria are met: >=2 different missense variants in the same codon have been classified as pathogenic (PM5_Strong). Occurs in the well-characterized ATP binding region of CDKL5 (PM1). This variant has been identified as a de novo occurrence in an individual with CDKL5 disorder without confirmation of paternity and maternity (PM6). PMID 30776697 Has been observed in at least 2 individuals with phenotypes consistent with CDKL5 disorder (PS4_Supporting). (PMID: 20397747, 30776697, Variation ID: 143828) Computational prediction analysis tools suggests a deleterious impact (REVEL score>= 0.75) (PP3). At least one individual with this variant has been reported with a clinical phenotype consistent with CDKL5- related condition (PP4).PMID: 30776697 This variant is absent from gnomAD (PM2_Supporting).

Developmental and epileptic encephalopathy, 2;CN128785:Angelman syndrome-like Pathogenic:1

Nov 11, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 20 of the CDKL5 protein (p.Gly20Arg). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with CDKL5-related conditions (PMID: 20397747, 30776697). In at least one individual the variant was observed to be de novo. ClinVar contains an entry for this variant (Variation ID: 143828). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt CDKL5 protein function with a positive predictive value of 95%. For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	30
DANN	Pathogenic	1.0
DEOGEN2	Benign	0.22	T;T;.;T;.;.;.;.
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.0	.;D;D;D;D;D;D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.99	D;D;D;D;D;D;D;D
MetaSVM	Pathogenic	0.90	D
MutationAssessor	Pathogenic	3.9	H;.;.;H;.;.;.;H
PhyloP100		8.4
PrimateAI	Pathogenic	0.92	D
PROVEAN	Pathogenic	-6.3	D;.;.;D;.;.;.;.
REVEL	Pathogenic	0.93
Sift	Pathogenic	0.0	D;.;.;D;.;.;.;.
Sift4G	Uncertain	0.0030	D;.;.;D;D;D;D;D
Vest4		0.96
ClinPred		1.0	D
GERP RS		4.7
Varity_R		0.99
gMVP		0.97
Mutation Taster		=3/97	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs267608418; hg19: chrX-18525274;