Background Recently, a triplication of the α-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 α-synuclein gene is pres-ent 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 α-Synuclein gene dosage values measured with real-time polymerase chain reaction. Results None of the samples showed α-synuclein triplication, duplication, or deletion. Conclusion Alterations in α-synuclein gene dosage are rare in familial PD.
