Pediatric-onset <i>PRKN</i> disease:New insights into an understudied population.

Background In pediatric age, the PRKN mutation is reported as one of the most common genetic causes of Parkinson's disease. However, detailed clinical data on PRKN patients with pediatric onset are scarce. Objective To describe clinical characteristics, disease progression, and management of PRKN patients with pediatric onset. Methods PRKN patients with onset of clinical signs before the age of 18 years were included in this retrospective multicenter study. Collected data included detailed clinical characteristics, progression, and disease management. Data presentation is descriptive due to the sample size. Results Nine patients (five females) were included from five French movement disorders centers. The mean age at symptom onset was 10.78 ± 2.22 years (median, 11; range, 7–14). Dystonia was the first most common motor symptom (six patients). The mean time from symptom onset to genetic diagnosis was 13.33 ± 9.21 years (median, 11; range, 3–32). The most commonly reported non-motor symptoms were sleep disorders (seven patients), anxiety (six patients), and depression (five patients). The first treatment was L-dopa in four patients, dopamine agonist in two, carbamazepine in two, and rasagiline in one. Dyskinesia and impulse control disorders were the most common treatment-related side effects (nine and six patients, respectively). Four patients underwent deep brain stimulation surgery. The last available follow-up was at 27.22 ± 14.05 years (median, 28; range, 6–56) after the diagnosis. Conclusions This is the first study reporting detailed clinical features and long-term management of PRKN patients with pediatric onset. Prompt diagnosis and appropriate treatment strategies are important to optimize disease management.