The autosomal dominant mutation of guanylate cyclase activator 1A (GUCA1A), which alters the structure and function of guanylyl cyclase-activating protein 1, is associated with both cone and cone-rod dystrophies [94], usually presenting between the third and fifth decade of life with mild photophobia and reduced central vision [17,95]. The gene discussed is GUCA1A; the disease is cone-rod dystrophy.