Comprehensive assessment reveals numerous clinical and neurophysiological differences between MECP2-allelic disorders

Area of Science:

• Neuroscience
• Genetics
• Clinical Medicine

Background:

• Rett syndrome (RTT) and MECP2 duplication syndrome (MDS) arise from MECP2 gene dosage abnormalities.
• Genetic therapies aim to correct MECP2 levels, but precise dosage is critical to avoid adverse outcomes.
• Distinguishing between RTT and MDS is crucial for targeted therapeutic development.

Purpose of the Study:

• To identify distinct clinical and neurophysiological biomarkers differentiating RTT from MDS.
• To establish reliable markers for monitoring therapeutic interventions in MECP2-related disorders.

Main Methods:

• Prospective enrollment of 11 MDS and 6 male RTT-like (MRL) individuals.
• Comprehensive clinical and neurophysiological assessments over two visits.
• Analysis of sleep physiology, tremor, stereotypies, and epilepsy characteristics.

Main Results:

• Identified unique clinical features: MRL individuals showed whole-body tremor and midline stereotypies, while MDS patients exhibited hand-flapping.
• Neurophysiological differences included altered sleep patterns (reduced sleep time, modified delta and alpha power) and distinct electroencephalogram (EEG) features.
• Specific differences in sleep spindle duration and amplitude were observed between MDS and MRL groups.

Conclusions:

• Distinct clinical and neurophysiological profiles differentiate MDS and MRL.
• These features can serve as valuable biomarkers for clinical trials.
• Biomarkers can aid in monitoring target engagement, disease progression, and safety during interventional studies for MECP2 disorders.