Observational Study Discovers a Reliable Measure of CDKL5 Deficiency Disorder

Research study background

Children and adults with CDD, part of a larger group of neurodevelopmental disorders called developmental and epileptic encephalopathies, face a complex combination of early-onset epilepsy, profound developmental impairments and multiple comorbidities that affect nearly every aspect of their lives. Despite the severity of this condition, clinical trials have long lacked outcome measures capable of capturing the full spectrum of symptoms that matter most to families.

As gene‑targeted and disease‑modifying therapies for CDD move rapidly toward clinical trials, the absence of validated, sensitive and comprehensive clinical outcome assessments has become a major barrier to trial readiness. To address this gap, investigators from the International CDKL5 Clinical Research Network integrated clinician‑reported measures, caregiver‑reported assessments, communication scales and sleep evaluations into a unified analytic model. According to Tim Benke, MD, PhD, this model could help both families and physicians.

"For future clinical trials involving disease-modifying therapies for CDD patients, our approach offers a reliable method for measuring improvements that allow government agencies, clinicians and families to make informed decisions when choosing therapies," Dr. Benke says.

Researchers' goal was to create a global severity score that reflects the interconnected nature of CDD symptoms, reduces measurement limitations and provides a reliable, externally validated framework that detects meaningful change in upcoming gene therapy trials.

Relevance to future research

The findings of this study underscore the longstanding challenges in measuring disease severity in CDKL5 deficiency disorder and other developmental and epileptic encephalopathies. Despite the multisystem brain impairments seen in CDD, most traditional developmental assessments are not designed for individuals with severe disabilities and frequently “bottom out,” limiting their ability to detect meaningful improvements. This study demonstrates that a unified global severity score can capture the complexity of CDD more accurately than any single measure alone.

Investigators emphasized that developing a reliable and externally validated severity metric is essential for advancing clinical trial readiness. The global severity score offers a promising framework for this purpose, providing a standardized way to quantify severity, develop a treatment target and track change over time.

Together, these findings reinforce how urgently the CDD community needs outcome measures that reflect the true complexity of this disorder across multiple domains of a child's life. Ongoing work across the ICCRN continues to build on this foundation, highlighting both the progress made and the critical need for broader training, infrastructure and collaboration to ensure families and clinicians are fully prepared and supported for the next era of CDD therapeutics.

The ICCRN is funded by the International Foundation for CDKL5 research (Scott Demarest, MD, Principal Investigator). This study is funded by the NIH-NINDS (U01NS114312, Tim Benke MD PhD, Project director).