To describe the demographic pattern and the clinical characteristics of the patients with Early Onset Parkinson's Disease (EOPD) at the Mayo Clinic.

The causes of EOPD remain undefined; the clinical course and phenotypical characteristics of EOPD are different than those of late onset Parkinson disease. Unfortunately, there is still a gap of knowledge on EOPD. 

We retrieved all the patients with EOPD that have visited the Mayo Clinic from 1990 to 2022 using Mayo Data Explorer (MDE). We included patients with a diagnosis of Parkinson’s disease (PD) at or before the age of 50 years old (according to the current Movement Disorder Society (MDS) recommendation on EOPD). In addition, we assessed the clinical features of those who were included. 

A total of 838 (518 males and 320 females) patients with EOPD were included with a mean age at symptoms onset of 40.6 ± 6.7 years. Overall, 13.6% had a family history of PD, with only 4.5% with genetic testing. Resting tremor was reported in 84.8%, bradykinesia in 85.9%, rigidity in 81.3% and postural instability in 13.1%. Dyskinesias were documented in 44.4% with a mean time from PD diagnosis of 10.5 ± 6.2 years. Cognitive impairment was reported in 19.3% of patients with a mean time from PD diagnosis of 16.8 ± 14.3 years.

We described the clinical characteristics of the EOPD in a large cohort. EOPD displays distinct clinical patterns regarding symptoms, progression, cognitive decline and response to medications. These differences may reflect multifactorial causes such as pathophysiological backgrounds and genetic, environmental, or age-related factors.