Failure to find alpha-synuclein gene dosage changes in 190 patients with familial Parkinson disease

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.