Ubiquitin Carboxyl-Terminal Esterase LI (UCHLI) SI8Y Polymorphism in Patients with Cataracts

Background: Cataract is characterized by light-scattering protein aggregates. The ubiquitin-proteasome system has been proposed a role in proteolytic removal of these protein aggregates. Ubiquitin carboxyl-terminal esterase L1 (UCHL1) is a de-ubiquitinating enzyme with important functions in recycling of ubiquitin. A protective role of the p.S18Y polymorphism of the UCHL1 gene has been shown in Parkinson's disease. The current study aimed to examine possible effects on cataract formation. Methods: Patients with cataract (n = 493) and controls (n = 142) were analyzed for the UCHL1 p.S18Y polymorphism using dynamic allele-specific hybridization. Results: Significant differences were observed in allele and genotype frequencies of the p.S18Y polymorphism between controls and cataract patients, where a positive UCHL1 allele A carrier status was associated with the cataract diagnosis (adjusted OR 1.7 [95% CI = 1.1-2.6] p = 0.02). No significant differences were seen in genotype distribution when stratifying for type of cataract. Nor did the mean age at cataract surgery differ between genotypes. Conclusion: The current study does not support a protective role for the UCHL1 S18Y polymorphism in cataract development, but may instead suggest a disease-promoting effect.