Background: Recently, a triplication of the alpha-synuclein locus was found associated with autosomal dominant Parkinson disease in a large family.
Objective: To determine whether a triplication or some other dosage alteration in the alpha-synuclein gene is present in one or more patients with familial PD in a large multinational collective.
Design: Retrospective recruitment of the largest families who were willing to cooperate with the study.
Setting: Centers with specialization in movement disorders genetics.
Patients: One hundred ninety unrelated patients with familial PD from Germany, Portugal, and Yugoslavia.
Main outcome measures: Alpha-synuclein gene dosage values measured with real-time polymerase chain reaction.
Results: None of the samples showed alpha-synuclein triplication, duplication, or deletion.
Conclusion: Alterations in alpha-synuclein gene dosage are rare in familial PD.