The purposes of this study are to identify persons with rapid-onset dystonia-parkinsonism (RDP) or mutations of the RDP gene, document prevalence of the disease, and map its natural history.

Rapid-onset dystonia-parkinsonism (RDP) is a rare, movement disorder with variable characteristics ranging from sudden onset (hours to days) of severe dystonic spasms to gradual onset of writer's cramp. RDP has elements of both dystonia and Parkinson's disease-two neurological diseases with motor and neuropsychological symptoms that hinder the quality of life. An internal trigger associated with extreme physiological stress has been reported prior to abrupt symptom onset of RDP.

This study, which is a continuation of an earlier study begun by Dr. Allison Brashear, aims to more clearly identify the characteristics associated with RDP and to explore whether mutations in the RDP gene are associated with atypical dystonias, Parkinson's disease, and other movement disorders.

The study involves in-person or remote (telemedicine) neurological assessments and blood samples for genetic analysis.

Inclusion Criteria:

• clinical presentation consistent with ATP1A3 disease (RDP, AHC) or confirmed diagnosis of RDP or AHC

Exclusion Criteria:

• none

Selection will take place predominantly via primary care clinics, i.e., physician referrals when patients present with a movement disorder suspicious for RDP.