Longitudinal Phenotypic Trajectories in GNAO1-Related Disorders: Defining Disease Progression and Clinical Profiles

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Pathogenic variants in GNAO1 gene lead to a range of neurological conditions including epilepsy, movement disorders, and developmental delays.
• The clinical heterogeneity and lack of understanding of disease progression complicate prognosis and therapeutic strategies for GNAO1-related disorders (GNAO1-RD).

Purpose of the Study:

• To conduct the first longitudinal natural history study of GNAO1-related disorders (GNAO1-RD) to precisely define phenotypic trajectories.
• To establish genotype-phenotype correlations and develop a severity score for risk stratification.

Main Methods:

• A cross-sectional analysis of 66 individuals with GNAO1-RD was performed.
• A prospective natural history arm enrolled 21 patients for annual standardized evaluations using validated clinical scales from March 2021 to December 2024.
• Molecular functional analysis was conducted for 20 missense variants.

Main Results:

• The cohort displayed significant variability in phenotype and severity, with neurodevelopmental impairments, universal movement disorders (95.5%), and epilepsy (51.5%).
• Longitudinal data indicated overall stability or mild improvement in most functional domains, with no significant global deterioration observed.
• Severe cases showed a progressive worsening of movement disorders, contributing to cumulative functional burden.

Conclusions:

• GNAO1-RD generally follows a non-degenerative course, characterized by stability or mild improvements in cognition, language, adaptive skills, and motor function.
• While global severity remains stable, severe GNAO1-RD involves progressive movement disorders rather than widespread neurodegeneration.
• Genotype-phenotype correlations and a developed severity score aid in early risk stratification and personalized treatment development for GNAO1-RD.