Objective: To explore the association of the microsatellite polymorphisms in the promoter region of alpha-synuclein gene with the late-onset sporadic Parkinson's disease (PD) susceptibility.
Methods: The microsatellite polymorphism of alpha-synuclein gene was analyzed with amplified fragment length polymorphism (Amp-FLP) and semiautomatic fluorescent labeled genotyping technique. Association analysis was performed in 135 unrelated late-onset sporadic PD patients and 170 age-matched healthy controls.
Results: The distribution of the alleles of the dinucleotide repeats variants of alpha-synuclein gene promoter region in PD cases was significantly different from that in the healthy controls. The most frequent allele in PD patients was allele 269 bp, but in controls it was the 271 bp allele. Alleles of <or=267 bp showed positive correlation with PD risk (OR=5.228, 95%CI: 1.248-27.202, chi-square=6.416, P=0.011), while the 273 bp allele was negatively correlated to PD (OR=0.638, 95%CI: 0.440-0.926, chi-square=5.644, P=0.018). Furthermore, no difference of genotype polymorphism distribution was shown between the two groups (chi-square=16.368, df=12, P=0.175). But the genotypes containing <or=267 bp allele may increase the susceptibility to PD (OR=4.594, 95%CI: 0.94-22.49, chi-square=4.224, P=0.04). Heterozygosity was 40% in PD patients, and 50% in controls.
Conclusion: alpha-synuclein microsatellite polymorphism might be a genetic susceptibility factor for late-onset sporadic PD.