Fernandez-Funez et al. (2000) reported that inducing the expression of polyQ expanded ATXN1 in retina of drosophila subsequently developed a progressive loss of retinal cell bodies and axonal projections. CAG-repeat expansion on SCA1 may have a possibility to affect nearby multiple genes such as the genes peripherin-2, which is essential for photoreceptor formation and maintenance, and guanylate cyclase activator 1a, a causal gene for cone dystrophy, located in 6p21.1 (Conley et al., 2019) (Manes et al., 2017). The gene discussed is ATXN1; the disease is cone dystrophy.