Recognizing Atypical Dopa-Responsive Dystonia and Its Mimics.

PURPOSE OF REVIEW

Dopa-responsive dystonia (DRD) encompasses a group of phenotypically and genetically heterogeneous neurochemical disorders. Classic GTP cyclohydrolase 1 ()-associated DRD consists of early-onset lower limb asymmetrical dystonia, with sleep benefit, diurnal variation, and excellent and sustained response to low l-dopa doses.

RECENT FINDINGS

Unlike the classic phenotype, -associated DRD may include features inconsistent with the original phenotype. We describe a -associated late-onset DRD case with a family history of parkinsonism and cervical dystonia whose response to levodopa was poor and complicated with dyskinesia, blepharospasm, and severe nonmotor symptoms. We use this case as a springboard to review the spectrum of atypical DRD, DRD-plus, and DRD mimics.

SUMMARY

-related dystonia may exhibit wide intrafamilial phenotypic variability, no diurnal fluctuation, poor response to l-dopa, and such complications as dyskinesia, epilepsy, sleep disorders, autonomic dysfunction, oculogyric crisis, myoclonus, or tics. More recently, rare variants have been found to be associated with Parkinson disease. Clinicians should be aware of atypical DRD, DRD-plus, and DRD mimics.