Functional skills in MECP2 duplication syndrome: developmental dynamics and regression

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• MECP2 duplication syndrome (MDS) is a rare X-linked neurodevelopmental disorder with poorly understood natural history and variable phenotypes.
• Limited data exists on skill acquisition, retention, and loss in individuals with MDS, particularly concerning gross motor, fine motor, and communication skills.

Purpose of the Study:

• To characterize the developmental trajectory of functional skills in the largest case series of MECP2 duplication syndrome to date.
• To investigate factors influencing skill acquisition and loss, including sex, age, seizures, and duplication size.

Main Methods:

• Retrospective analysis of functional skill data from 160 individuals with genetically confirmed MDS.
• Data collection included parent-reported information on gross motor, fine motor, communication, and feeding skills.
• Statistical analysis was performed to compare skill acquisition and regression rates based on sex, age, seizure status, and genetic duplication length.

Main Results:

• Phenotypic variability observed, with some females exhibiting similar functional deficits to males, though females had higher gross and fine motor skill acquisition rates.
• Most common skill regressions included speech (38%), fine motor/hand function (29%), walking (28%), and feeding (28%).
• Seizures, increasing age, and larger duplication lengths (>1 Mb) were associated with lower functional abilities and reduced likelihood of acquiring independent walking.

Conclusions:

• This study provides a comprehensive baseline for understanding the natural history of functional skill development in MDS.
• Functional skill deficits are influenced by sex, age, comorbidities like seizures, and genetic factors such as duplication size.
• Further research is needed to explore the impact of interventions on skill maintenance in individuals with MDS.