UCHL1 and early-onset autosomal dominant Alzheimer disease: In Huntington's disease, the UCHL1 p.S18Y variant is linked to age at onset.8 For Alzheimer's disease (AD), a Chinese study has demonstrated lower frequencies of the A allele and the AA genotype in female AD patients as compared to female controls.9 However, other studies could not find an association between UCHL1 genotypes and AD.10,11 UCHL1 is expressed mostly in neural tissues, but there are also some reports of other non-neural tissues expressing UCHL1.12 There are few reports on UCHL1 expression in the eye.