CACD is an inherited retinal dystrophy causing dysfunction of photoreceptors and visual acuity usually between ages 30 and 60, resulting in a well-demarcated macular area of outer retinal, RPE, and choriocapillaris atrophy.[130] It is usually AD,[162] with PRPH2 mutations being the most common, although AR cases have been reported.[163]. The gene discussed is PRPH2; the disease is Alzheimer disease.