The Movement Disorder Spectrum of <i>ATP1A3</i> ‐Related Disorders: Cross‐Sectional Analysis and Video Archive of 88 Patients

The extensive clinical heterogeneity in ATP1A3-related disorders challenges rigid phenotypic classifications. The predominance of patients with overlapping or atypical features supports a shift toward flexible, symptom-based clinical approaches rather than strict reliance on canonical phenotype recognition. © 2026 International Parkinson and Movement Disorder Society.