The REP1 SNP is a triallelic polymorphism with the longest (263 bp) and intermediate length (261 bp) alleles usually associated with an increased risk for PD, as seen in studies with North American [47, 50, 60, 64, 65, 68, 71, 72, 75, 81], German [73], Greek [79], and Dutch [77] samples. This evidence concerns the gene CHM and Parkinson disease.