A polymorphic variation of serine to tyrosine at codon 18 in the ubiquitin C-terminal hydrolase-L1 gene is associated with a reduced risk of sporadic Parkinson's disease in a Japanese population.
Finally, in an updated S18Y-PD meta-analysis (6,594 subjects), no significant association was observed under additive, recessive, or dominant models (odds ratio = 1.00 [95% confidence interval: 0.74-1.33]; odds ratio = 1.01 [95% confidence interval: 0.76-1.35]; and odds ratio = 0.96 [95% confidence interval: 0.86-1.08], respectively), and a cumulative meta-analysis showed a trend toward a null effect.
Since a substitution of serine by tyrosine at codon 18, exon 3 (S18Y polymorphism) of the UCH-L1 gene exhibits a protective effect against the development of degenerative disease such as sporadic Parkinson's disease (PD) in several different ethnic groups, we hypothesized that UCH-L1 gene S18Y polymorphism may have that same effect on the pathologic process of AD.
We conclude that the S18Y variant of UCH-L1 confers a novel antioxidant function that is not present in the WT form and that this function may underlie the protective effects of this variant in certain PD populations.