HPGDS and cataract: Certain genes also showed abnormal methylation profiles specifically in the pandas with cataracts, including the cysteine-aspartate protease gene CASP3, a pro-apoptotic mediator already linked to cataracts in rats [18, 19], and the glutathione S-transferase gene GSTM3, which is expressed in the lens tissues of human patients with age-related cataracts [20].