A prospective study of familial versus sporadic Parkinson's disease.

Background: Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Most cases are sporadic but about 10-15% of patients have a positive family history of PD.

Objective: To compare clinical phenotypes between familial (fPD) and sporadic (sPD) PD patients.

Methods: Fifty-nine consecutive patients with at least one first-degree relative with PD were prospectively studied. After exclusion of 9 PD patients with positive family carrying known disease causing mutations, the remaining 50 were compared with 50 age- and sex-matched sPD patients.

Results: Despite our methodological approach (strict diagnostic criteria, validated scales, structured interviews, multi- and two-member group formation and exclusion of patients with identifiable mutations) no major differences in the clinical phenotype between fPD and sPD were found.

Conclusion: Similar phenotypic characteristics of motor signs and symptoms suggest that at least the topography of the neurodegenerative insult leading to the parkinsonian clinical syndrome in fPD and sPD is similar. Similar etiologies are also suggested.