Essential tremor is not associated with a-synuclein gene haplotypes

A specific allele of the NACP-Rep1 polymorphism within the -synuclein promoter was found to be associated both with Parkinson's disease and essential tremor. We repeated the association study on a large series of Italian patients with essential tremor using a panel of polymorphisms within the -synuclein gene. Our results did not confirm the association reported previously and failed to identify a -synuclein specific haplotype as susceptibility factor for essential tremor.