X-18604218-AAGT-A

Variant names:

• chrX-18604218-AAGT-A
• rs1555951997
• NM_001323289.2:c.1296_1298delGTA

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2_Supporting PM4_Supporting

This summary comes from the ClinGen Evidence Repository: The p.Lys432_Tyr433delinsAsn variant in CDKL5 is absent from gnomAD (PM2_supporting). The p.Lys432_Tyr433delinsAsn variant causes a change in the length of 1 amino acid in the protein due to an in-frame deletion or insertion in a non-repeat region of CDKL5 (PM4_supporting). In summary, p.Lys432_Tyr433delinsAsn variant in CDKL5 is classified as a variant of uncertain significance based on the ACMG/AMP criteria (PM2_supporting, PM4_supporting). LINK:https://erepo.genome.network/evrepo/ui/classification/CA645373290/MONDO:0100039/016

• Frequency: Genomes: not found (cov: 22)
• Consequence: CDKL5 NM_001323289.2 disruptive_inframe_deletion
• Clinical Significance: Uncertain significance reviewed by expert panel U:3
• Conservation: PhyloP100: 8.94
• Publications: 0 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: Uncertain_significance. The variant received 2 ACMG points.

• PM2: For more information check the summary or visit ClinGen Evidence Repository.
• PM4: For more information check the summary or visit ClinGen Evidence Repository.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001323289.2. 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
	CDKL5	NM_001323289.2	MANE Select	c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 12 of 18	NP_001310218.1
	CDKL5	NM_001037343.2		c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 13 of 22	NP_001032420.1
	CDKL5	NM_003159.3		c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 12 of 21	NP_003150.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	CDKL5	ENST00000623535.2	TSL:1 MANE Select	c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 12 of 18	ENSP00000485244.1
	CDKL5	ENST00000379989.6	TSL:1	c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 13 of 22	ENSP00000369325.3
	CDKL5	ENST00000379996.7	TSL:1	c.1296_1298delGTA	p.Lys432_Tyr433delinsAsn	disruptive_inframe_deletion	Exon 12 of 21	ENSP00000369332.3

Frequencies

GnomAD3 genomes Cov.: 22

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 22

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: reviewed by expert panel

Submissions by phenotype

not specified Uncertain:1

Nov 12, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

CDKL5 disorder Uncertain:1

Aug 27, 2025

ClinGen Rett and Angelman-like Disorders Variant Curation Expert Panel

Significance: Uncertain significance

Review Status: reviewed by expert panel

Collection Method: curation

The p.Lys432_Tyr433delinsAsn variant in CDKL5 is absent from gnomAD v4.1 (PM2_supporting). The p.Lys432_Tyr433delinsAsn variant causes a change in the length of 1 amino acid in the protein due to an in-frame deletion or insertion in a non-repeat region of CDKL5 (PM4_supporting). In summary, p.Lys432_Tyr433delinsAsn variant in CDKL5 is classified as a variant of uncertain significance based on the ACMG/AMP criteria (PM2_supporting, PM4_supporting). (CDKL5 Specifications v.5; curation approved on 8/27/25)

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

May 15, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant, c.1296_1298del, results in the deletion of one amino acid(s) of the CDKL5 protein (p.Lys432_Tyr433delinsAsn), but otherwise preserves the integrity of the reading frame. This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with CDKL5-related conditions. ClinVar contains an entry for this variant (Variation ID: 434662). Experimental studies and prediction algorithms are not available or were not evaluated, and the functional significance of this variant is currently unknown. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		8.9

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: rs1555951997; hg19: chrX-18622338;