Expanding the clinical phenotype of DYT5 mutations: is multiple system atrophy a possible one?

Autosomal dominantly inherited mutations in the GTP cyclohydrolase 1 (GCH1) gene are associated with dopamine-responsive dystonia (DRD), also known as DYT5. Rare atypical presentations have been described, including adulthood Parkinson disease (PD) with in vivo evidence of nigrostriatal degeneration.