Cone-rod dystrophy-15 (CORD15) is characterized by onset of reduced vision in the third to fifth decades of life. Visual acuity progressively worsens, and most patients exhibit reduced color vision and central scotomas (Cohen et al., 2012; Sobolewska et al., 2023). Retinitis pigmentosa-65 (RP65) is an adult-onset form of RP, with night blindness developing in the second to fourth decades of life. In addition to constriction of visual fields, patients may experience photophobia, reduced visual acuity, and difficulties with color vision (Henderson et al., 2010; Bessette et al., 2018; Dawood et al., 2021). Retinal macular dystrophy-5 (MCDR5) is a late-onset form of macular dystrophy, with most patients noting symptoms in the fourth to sixth decades of life. Symptoms include reduced visual acuity, glare, poor contrast vision, and metamorphopsia; night blindness is uncommon (Stingl et al., 2017; Charbel Issa et al., 2019; Ba-Abbad et al., 2021). Macular atrophy is a characteristic feature in all patients, and early involvement may be observed even in patients with RP who exhibit relatively preserved visual acuity (Malechka et al., 2022).
For a general phenotypic description and a discussion of genetic heterogeneity of cone-rod dystrophy, see 120970; for retinitis pigmentosa, see 268000; for retinal macular dystrophy, see 136550.
Reviews
Bessette et al. (2018) reviewed published reports of patients with disease-causing mutations in the CDHR1 gene. The median age of patients was 36 years, and the majority retained visual acuity of 20/70 or better in at least one eye. Most patients developed symptoms between the first and third decades of life (range, infancy through fourth decade). Night blindness was the most common presenting symptom (54%), followed by photosensitivity (39%) and decreased vision (31%). Macular atrophy was the most common fundus feature reported (96%), followed by vascular attenuation (69%) and peripheral bone spicules (54%). The authors noted significant inter- and intrafamilial phenotypic variability among patients with CDHR1 mutations. [from
OMIM]