Failure to find the a‐synuclein gene missense mutation (G ²⁰⁹ A) in 100 patients with younger onset Parkinson's disease

The missense G209A mutation at exon 4 of the alpha-synuclein gene was recently found to be responsible for familial Parkinson's disease (PD) in a large kindred of Italian descent. We studied 100 typical PD patients with onset before age 51, both with and without a family history of PD. We did not find this alpha-synuclein missense mutation in any patient, but it was present in a symptomatic member of the Contursi family.