Cone-rod dystrophy 16

Cone-rod dystrophy (CORD) and retinitis pigmentosa (RP) are clinically and genetically overlapping heterogeneous retinal dystrophies. RP is characterized initially by rod photoreceptor dysfunction, giving rise to night blindness, which is followed by progressive rod and cone photoreceptor dystrophy, resulting in midperipheral vision loss, tunnel vision, and sometimes blindness. In contrast to RP, CORD is characterized by a primary loss of cone photoreceptors and subsequent or simultaneous loss of rod photoreceptors. The disease in most cases becomes apparent during primary-school years, and symptoms include photoaversion, decrease in visual acuity with or without nystagmus, color vision defects, and decreased sensitivity of the central visual field. Because rods are also involved, night blindness and peripheral vision loss can occur. The diagnosis of CORD is mainly based on electroretinogram (ERG) recordings, in which cone responses are more severely reduced than, or equally as reduced as rod responses (summary by Estrada-Cuzcano et al., 2012).

OMIM