Updated: Apr 25
CDKL5 deficiency disorder (CDD) is a rare developmental epileptic encephalopathy (DEE) caused by mutations in the CDKL5 gene. CDD has been classified as a DEE because the genetic change causes both the epileptic activity as well as the severe impairment of development. CDD can manifest in a broad range of clinical symptoms and severity. Although rare, the occurrence could be ~1:40,000 -75,000 live births, making it one of the most common forms of genetic epilepsy. Previously known as serine/threonine protein kinase 9 (STK9), CDKL5 stands for cyclin-dependent kinase-like 5, and mutations in this gene were first identified as disease-causing in 2004. The CDKL5 gene provides instructions for making proteins essential for normal brain and neuron development and is located on the X chromosome. Mutations in the CDKL5 gene can reduce the amount of functional CDKL5 protein or alter its activity in neurons, but it is unclear how these changes cause the specific features of CDD. The CDKL5 protein acts as a kinase, which is an enzyme that changes the activity of other proteins by adding oxygen and phosphate atoms (a phosphate group) at specific positions. Most of the CDKL5 gene mutations are “de novo,” meaning that they occur spontaneously and are not inherited. However, rare families in which multiple siblings were affected with the same mutation have been reported. Because males have only one X chromosome in each cell, the mutated version of the CDKL5 gene is active in all cells. Affected males have no normal copies of the gene; however, some have evidence of two or more populations of cells with different genotypes (mosaicism). Although many identified patients are males, this disorder mainly affects females because of the location of the gene. Males and females appear to be similarly affected.
CDKL5 Deficiency Disorder (CDD) Clinical Features
The hallmarks of CDD are early-onset, intractable epilepsy and neurodevelopmental delay impacting cognitive, motor, speech, and visual function. Seizures in CDKL5 deficiency disorder usually begin within the first three months of life and can appear as early as the first week after birth. The types of seizures change with age and may follow a predictable pattern. Seizures occur daily in most people with CDKL5 deficiency disorder, although they can have periods when they are seizure-free. Seizures in CDKL5 deficiency disorder are typically resistant to treatment. Development is globally impaired in children with CDKL5 deficiency disorder, and support for all activities of daily living is necessary. Most have a severe intellectual disability and little or no speech. The development of gross motor skills, such as sitting, standing, and walking, is delayed or not achieved. About one-third of affected individuals can walk independently. Fine motor skills, such as picking up small objects with the fingers, are also impaired; about half of affected individuals have purposeful use of their hands. Most people with this condition have vision problems (cortical visual impairment).
Get to Know The International Foundation for CDKL5 Research
The International Foundation for CDKL5 Research began as a group of parents whose children had CDKL5 Deficiency Disorder. We came together and dared to dream of a new future for our children. With education and research, we believe a life-changing cure can be found. In 2009, we incorporated the International Foundation for CDKL5 Research as a non-profit organization. Since then, we have gone on to fund ground-breaking research and establish CDKL5 Centers of Excellence across the United States. Our mission is to treat and cure CDKL5 Deficiency Disorder by funding scientific research while helping affected individuals and their families to thrive. We are committed to funding research, both scientific and clinical, that will bring about treatments and, ultimately, a cure for CDKL5. We strive to raise awareness of this rare disorder within the medical and lay communities. Above all, we seek to support all CDKL5 families and caregivers, whether newly diagnosed or well into adulthood, by providing peer support and the most current information on treatment advances and how to live their best life.
I am especially proud of ...
Our community has made a tremendous impact on research! There was very little known about the genotype or phenotype of CDD when IFCR began our mission. In less than a decade, we have harnessed partnerships to leverage our resources and provide the research community necessary tools for drug development. Funding the development of multiple mouse models (including a reversible model), zebrafish, iPSC lines, antibody development, and an International Registry and Database prepared the community for current clinical trials. We hosted the Inaugural CDKL5 Family & Science Conference in New Orleans during the 7th World Rett Congress for Rett Syndrome in 2012 and have gathered biennially since. By 2013 we were positioned to establish CDKL5 Centers of Excellence (COEs), which provide multi-disciplinary clinical care and clinical research. There are eight centers located across the USA working together to develop Standards of Care and natural history data. Bringing families together is genuinely at the heart of our organization, the soul of our success. As the genetic revolution marches on, we continue to focus on what we can do to support our community today while working towards brighter tomorrows.
Excited to REN because...
IFCR believes that the rare genetic epilepsies under the REN umbrella share more in common than they differ. Thus, there are opportunities for small patient advocacy groups to move further faster collaboratively studying our disorders in a gene agnostic manner comparing symptoms within and across single DEE disorders.
My journey and motivation...
My oldest daughter, Ava, was seven months old when noticeable seizures came roaring into her life. We spent years dangling from a string while managing refractory epilepsy and chasing evidence that might explain her elusive neurological condition. After more than six years of guesstimating, an answer came in the spring of 2012 that identified the culprit in Ava’s complex medical puzzle. Her neuro-metabolic team had finally identified the small deletion in her CDKL5 gene. It was liberating to have a diagnosis and delightful to find the International Foundation for CDKL5 Research in existence. Ava is nearly 15, and I owe so much of my sanity to this gig. IFCR has provided me space to focus my energy constructively - I embrace the spirit of perseverance and strive to leave the community more fruitful than I found it.
By Amanda Jaksha, Treasurer, International Foundation for CDKL5 Research. As part of the executive team, I manage many of the day-to-day operations of the organization. I often joke that I am the jack of all trades and master of none in this domain. I am a managerial accountant (BS) by education. I also hold a certified nurse assistant (CNA) license and participate in my child’s home health care plan as an employee of a large home healthcare agency.