Observational Study to Characterize Biomarkers and Disease Progression in Participants With Methyl CpG Binding Protein 2 (MECP2) Duplication Syndrome

This is a multi-center, non-randomized, non-interventional prospective and retrospective study in up to 40 participants with MECP2 duplication syndrome (MDS) who can undergo general anesthesia or conscious sedation to collect fluid biomarkers (CSF and blood), undergo electrophysiological assessments (electroencephalogram \[EEG\], evoked potentials \[EP\], pupillometry), clinical assessments and caregiver reported outcomes measures, to be used in support of the development of therapies for MDS. The study duration for each participant will be approximately 110 weeks.