Definition:

Central areolar choroidal dystrophy (CACD) is a hereditary retinal disorder that principally affects the macula, often resulting in atrophy of the retinal pigment epithelium and choriocapillaris in the center of the macula. Dysfunction of macular photoreceptors usually leads to a decrease in visual acuity, generally occurring between the ages of 30 and 60 years. Autosomal-recessive cases that is caused by mutations in GUCY2D have been reported. However, in most cases, CACD is inherited as an autosomal-dominant trait. Autosomal-dominant CACD is genetically heterogeneous but mutations in the peripherin/RDS gene (PRPH2) seem to be the most common cause. The PRPH2 encodes a photoreceptor-specific glycoprotein. It is believed to play an important role in the assembly, orientation, and physical stability of photoreceptor outer segment disks.