A novel RPGR mutation masquerading as Stargardt disease

An adult male was referred for a second opinion of his retinal dystrophy. His prior genetic testing identified an ABCA4 gene variant associated with Stargardt disease. He had an affected younger brother, and the rest of his family was reported to be asymptomatic. He wanted to know if he would qualify for any Stargardt gene or stem cell therapy trials. The adult male proband (III:A) experienced blurred central vision, nyctalopia and photophobia since childhood. His best-corrected visual acuity was 20/100 and 20/200, respectively. Fundus examination demonstrated a bull's eye maculopathy and peripapillary atrophy (figure 1). There was no intraretinal pigmentary migration, pisciform flecks, optic disc pallor or retinal vessel attenuation. Fundus autofluorescence revealed a prominent bull's eye pattern. Spectral domain optical coherence tomography showed foveal thinning (figure 2). These findings were not inconsistent with a cone dystrophy such as Stargardt Group II disease. Figure 1 Clinical Imaging. (A–F) Proband (III:1). Colour fundus images showed perifoveal pigment atrophy in a bull's eye pattern that was pronounced in autofluorescent imaging. SD-OCT revealed foveal thinning (arrows), loss of outer plexiform layer, ellipsoid and interdigitation line in both eyes with preservation of this structure outside macular. (G–L) Affected Brother (III:3). A similar bull's eye pattern with marked RPE atrophy was also observed in colour fundus, autofluorescent and SD-OCT images. …