Observational Study in Patients With Cyclin-dependent Kinase-like 5 Deficiency Disorder

This is an observational study to examine the presence of detectable differences in neurocognitive, developmental, motor, neurophysiologic, and quality of life measures over time in approximately up to 100 patients aged birth to 55 years and diagnosed with cyclin-dependent kinase-like 5 deficiency disorder. Operational performance across age groups and languages will be assessed throughout the study, and Baseline cohort characteristics will be assessed throughout enrollment.