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Reviewed December 2013

What is the official name of the CDKL5 gene?

The official name of this gene is “cyclin dependent kinase like 5.”

CDKL5 is the gene's official symbol. The CDKL5 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the CDKL5 gene?

The CDKL5 gene provides instructions for making a protein that is essential for normal brain development and function. The CDKL5 protein acts as a kinase, which is an enzyme that changes the activity of other proteins by adding a cluster of oxygen and phosphorus atoms (a phosphate group) at specific positions. One of the proteins targeted by the CDKL5 protein is MeCP2, which is produced from the MECP2 gene. The MeCP2 protein plays important roles in the function of nerve cells (neurons) and other brain cells and in the maintenance of connections (synapses) between neurons. Researchers have not determined which other proteins are targeted by the CDKL5 protein.

Does the CDKL5 gene share characteristics with other genes?

The CDKL5 gene belongs to a family of genes called CDK (cyclin-dependent kinases).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.

How are changes in the CDKL5 gene related to health conditions?

X-linked infantile spasm syndrome - caused by mutations in the CDKL5 gene

Mutations in the CDKL5 gene can cause a disorder known as X-linked infantile spasm syndrome, which is characterized by recurrent seizures called infantile spasms that begin in the first year of life. Children with this condition also have intellectual disability. X-linked infantile spasm syndrome caused by CDKL5 gene mutations occurs more often in females, but it has been identified in a small number of males.

Some cases of X-linked infantile spasm syndrome are caused by a deletion involving part or all of the CDKL5 gene; others result from mutations that alter the function of the CDKL5 protein or prevent the production of any functional protein. It is unclear how defects in this protein cause seizures and intellectual disability.

other disorders - caused by mutations in the CDKL5 gene

More than 10 mutations in the CDKL5 gene have been identified in females with a condition similar to Rett syndrome, which is a disorder whose characteristic features include developmental problems, loss of language skills, and repeated hand wringing or hand washing movements. Girls with CDKL5 gene mutations have many of the features of classic Rett syndrome. However, unlike girls with classic Rett syndrome, they also develop recurrent seizures beginning in infancy. Although this condition was previously described as an atypical form of Rett syndrome (often called the early-onset seizure variant), it is now usually considered to be a separate condition.

Some of the CDKL5 gene mutations that cause this condition change a single protein building block (amino acid) in a region of the CDKL5 protein that is critical for its kinase function. Other mutations lead to the production of an abnormally short, nonfunctional version of the protein. Researchers are working to determine how these changes impair brain development, resulting in seizures and features similar to Rett syndrome.

Where is the CDKL5 gene located?

Cytogenetic Location: Xp22

Molecular Location on the X chromosome: base pairs 18,425,605 to 18,660,858

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The CDKL5 gene is located on the short (p) arm of the X chromosome at position 22.

The CDKL5 gene is located on the short (p) arm of the X chromosome at position 22.

More precisely, the CDKL5 gene is located from base pair 18,425,605 to base pair 18,660,858 on the X chromosome.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about CDKL5?

You and your healthcare professional may find the following resources about CDKL5 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the CDKL5 gene or gene products?

  • CFAP247
  • cyclin-dependent kinase-like 5
  • serine/threonine kinase 9
  • STK9

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding CDKL5?

amino acid ; atypical ; deletion ; disability ; enzyme ; gene ; kinase ; oxygen ; phosphate ; phosphorus ; protein ; seizure ; serine ; syndrome ; threonine ; threonine kinase

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (12 links)


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Reviewed: December 2013
Published: February 8, 2016