Association of SNCA with Parkinson: replication in the Harvard NeuroDiscovery Center Biomarker Study.

Background: Mutations in the α-synuclein gene (SNCA) cause autosomal dominant forms of Parkinson's disease, but the substantial risk conferred by this locus to the common sporadic disease has only recently emerged from genome-wide association studies.

Methods: We genotyped a prioritized noncoding variant in SNCA intron 4 in 344 patients with Parkinson's disease and 275 controls from the longitudinal Harvard NeuroDiscovery Center Biomarker Study.

Results: The common minor allele of rs2736990 was associated with elevated disease susceptibility (odds ratio, 1.40; P = .0032).

Conclusions: This result increases confidence in the notion that in many clinically well-characterized patients, genetic variation in SNCA contributes to "sporadic" disease.