Polymeropoulos et al described the genetic linkage of a large Italian Parkinson’s disease pedigree (Contursi) to chromosome 4q21-q231; more recently the sequence of the α-synuclein gene located in this chromosomal region in affected patients from this kindred disclosed that most of the affected members were heterozygous for a missense mutation (alanine→threonine) at position 53 of the protein.2 This same missense mutation was also found in three additional unrelated families of Greek origin with Parkinson’s disease.

The mutation was found by DNA sequence analysis of the fourth exon of the α-synuclein gene, disclosing a single base pair change at position 209 from G to A (G209A), and creating a novelTsp …