A number of reports have demonstrated a protective effect of the UCHL1 p.S18Y polymorphism against sporadic PD in different populations,4,6,21,22 although conflicting data exist.23 As for AD, data on UCHL1 genotype frequencies and its effect on risk of AD is scarce and conflicting.9,10 To our knowledge, there are no previous reports on the effect of the UCHL1 p.S18Y genotype distribution in cataract patients. This evidence concerns the gene UCHL1 and Alzheimer disease.