Multiple alpha-synuclein gene polymorphisms are associated with Parkinson's disease in a Norwegian population.

Previous studies have found associations between Parkinson's disease (PD) and polymorphisms located within both the alpha-synuclein gene (SNCA) promoter and other gene regions. Our aim was to study SNCA gene markers in a closely matched Norwegian PD population to examine the genetic relationship between different polymorphisms associated with the disease. We genotyped seven single nucleotide polymorphisms (SNPs) located in the SNCA promoter and two SNPs in the 3' gene region and seven microsatellite markers located across the gene in a closely matched series of 236 PD patients and 236 controls. Linkage disequilibrium (LD) structure was examined, and association of single markers and gene haplotypes analyzed. Several markers located across the SNCA gene were associated with PD, including marker alleles associated with disease in previous studies (Rep1 263-bp allele, rs356165 and rs356219). LD between associated marker alleles located across the SNCA gene suggests that a single genetic effect might explain the previous reported association in the promoter and 3' regions.