| Prevalence | Rare; estimated 1-5% of parkinsonian disorders |
| Age of onset | Typically 60-75 years |
| Progression | Slowly progressive over 5-15 years |
| Sex distribution | Slight male predominance reported in some series |
| Freezing of Gait (FOG) | Sudden, episodic inability to step forward |
| Akinesia | Reduced spontaneous movements, particularly in the lower extremities |
| Start Hesitation | Marked difficulty initiating the first step |
| Turn-Freezing | Freezing specifically when attempting to turn |
| Festination | Progressive shortening of steps during walking |
| Postural instability | Frequent falls, often backward |
| Reduced arm swing | Bilateral rather than unilateral |
| Facial masking | Reduced facial expression |
| Databases | OMIMOrphanetClinicalTrialsPubMed |