The G209A mutation in the alpha-synuclein gene is not detected in familial cases of Parkinson disease in non-Greek and/or Italian populations.

OBJECTIVE To determine whether the G-to-A substitution at nucleotide 209 (G209A) mutation in the alpha-synuclein gene is responsible for familial Parkinson disease (PD) in the US population. DESIGN Polymerase chain reaction-based DNA analysis of consecutive patients with PD and family history of PD. SETTING A university-affiliated movement disorder clinic and a Veterans Affairs clinical research laboratory. PATIENTS Forty-four patients with PD and family history of PD and 29 patients with sporadic PD, all with no known Greek and/or Italian background. RESULTS None of the DNA samples showed the G209A mutation. CONCLUSION The G209A mutation is rare in US patients with familial PD.