Causal relation between α synuclein gene duplication and familial Parkinson’s disease

The α synuclein gene (SNCA) has been implicated in autosomal dominant forms of Parkinsons disease. We screened 119 individuals from families with this rar e form of the disease for SNCA duplications by semiquantitative multiplex PCR. T wo patients had duplications, which were confirmed by analysis of intragenic and flanking microsatellite markers. The phenotype in both patients was indistingui shable from idiopathic Parkinsons disease and no atypical features were presen t, by contrast with reports of families with triplication of the same gene. Thes e results indicate that SNCA is more frequently associated with familial Parkins ons disease than previously thought, and that there is a clear dosage effect a ccording to the number of supernumerary copies of this gene.