Neurodegeneration, particularly in the eye and brain, is a hallmark of many of these models, such as SCA3, SCA7, and dentatorubral-pallidoluysian atrophy (DRPLA), where retinal and neural tissue show progressive collapse, vacuolization, or loss of structure [82,100,114]. The gene discussed is ATXN3; the disease is dentatorubral-pallidoluysian atrophy.