rs921600020

Variant names:

• chrX-18604122-A-C
• rs921600020
• NM_001323289.2:c.1198A>C

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4 BP6

The NM_001323289.2(CDKL5):​c.1198A>C​(p.Asn400His) variant causes a missense change. The variant allele was found at a frequency of 0.00000182 in 1,098,196 control chromosomes in the GnomAD database, with no homozygous occurrence. There are no hemizygote samples in GnomAD. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 22)
  • Exomes 𝑓: 0.0000018 (0 hom. 0 hem.)
• Consequence: CDKL5 NM_001323289.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:1
• Conservation: PhyloP100: 6.92
• Publications: 1 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 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.37612605).
• BP6: Variant X-18604122-A-C is Benign according to our data. Variant chrX-18604122-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 569644.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
CDKL5	NM_001323289.2	c.1198A>C	p.Asn400His	missense_variant	Exon 12 of 18	ENST00000623535.2	NP_001310218.1
CDKL5	NM_001037343.2	c.1198A>C	p.Asn400His	missense_variant	Exon 13 of 22		NP_001032420.1
CDKL5	NM_003159.3	c.1198A>C	p.Asn400His	missense_variant	Exon 12 of 21		NP_003150.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
CDKL5	ENST00000623535.2	c.1198A>C	p.Asn400His	missense_variant	Exon 12 of 18	1	NM_001323289.2	ENSP00000485244.1

Frequencies

GnomAD3 genomes Cov.: 22

GnomAD4 exome AF: 0.00000182 AC: 2 AN: 1098196 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 363556

African (AFR) AF: 0.00 AC: 0 AN: 26402

American (AMR) AF: 0.00 AC: 0 AN: 35207

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 19386

East Asian (EAS) AF: 0.00 AC: 0 AN: 30206

South Asian (SAS) AF: 0.00 AC: 0 AN: 54148

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 40520

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 4137

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 842097

Other (OTH) AF: 0.0000434 AC: 2 AN: 46093

GnomAD4 genome Cov.: 22

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Inborn genetic diseases Uncertain:1

Apr 24, 2025

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.1198A>C (p.N400H) alteration is located in exon 12 (coding exon 11) of the CDKL5 gene. This alteration results from a A to C substitution at nucleotide position 1198, causing the asparagine (N) at amino acid position 400 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

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

Jan 12, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Uncertain	0.026	T
BayesDel_noAF	Benign	-0.20
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Benign	0.054	T;T;.;T;.;.
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.97	.;D;D;D;D;D
M_CAP	Pathogenic	0.66	D
MetaRNN	Benign	0.38	T;T;T;T;T;T
MetaSVM	Uncertain	-0.14	T
MutationAssessor	Uncertain	2.0	M;.;.;M;.;M
PhyloP100		6.9
PrimateAI	Uncertain	0.75	T
PROVEAN	Benign	-2.0	N;.;.;N;.;.
REVEL	Benign	0.25
Sift	Uncertain	0.0010	D;.;.;D;.;.
Sift4G	Uncertain	0.048	D;.;.;D;D;T
Polyphen		1.0	D;.;.;D;.;.
Vest4		0.74
MutPred		0.16		Loss of stability (P = 0.1219);Loss of stability (P = 0.1219);Loss of stability (P = 0.1219);Loss of stability (P = 0.1219);Loss of stability (P = 0.1219);Loss of stability (P = 0.1219);
MVP		0.88
MPC		0.87
ClinPred		0.89	D
GERP RS		6.1
Varity_R		0.58
gMVP		0.19
Mutation Taster		=73/27	polymorphism

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: rs921600020; hg19: chrX-18622242;