RPGR-associated dystrophies: Clinical, genetic, and histopathological features

Xuan-Thanh-An Nguyen, Mays Talib, Mary J. van Schooneveld, Joost Brinks, Jacoline ten Brink, Ralph J. Florijn, Jan Wijnholds, Robert M. Verdijk, Arthur A. Bergen, Camiel J. F. Boon

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Abstract

This study describes the clinical, genetic, and histopathological features in patients with RPGR-associated retinal dystrophies. Nine male patients from eight unrelated families underwent a comprehensive ophthalmic examination. Additionally, the histopathology of the right eye from a patient with an end-stage cone-rod-dystrophy (CRD)/sector retinitis pigmentosa (RP) phenotype was examined. All RPGR mutations causing a CRD phenotype were situated in exon ORF15. The mean best-corrected visual acuity (BCVA, decimals) was 0.58 (standard deviation (SD)): 0.34; range: 0.05–1.13); and the mean spherical refractive error was −4.1 D (SD: 2.11; range: −1.38 to −8.19). Hyperautofluorescent rings were observed in six patients. Full-field electroretinography responses were absent in all patients. The visual field defects ranged from peripheral constriction to central islands. The mean macular sensitivity on microperimetry was 11.6 dB (SD: 7.8; range: 1.6–24.4) and correlated significantly with BCVA (r = 0.907; p = 0.001). A histological examination of the donor eye showed disruption of retinal topology and stratification, with a more severe loss found in the peripheral regions. Reactive gliosis was seen in the inner layers of all regions. Our study demonstrates the highly variable phenotype found in RPGR-associated retinal dystrophies. Therapies should be applied at the earliest signs of photoreceptor degeneration, prior to the remodeling of the inner retina.
Original languageEnglish
Article number835
JournalInternational journal of molecular sciences
Volume21
Issue number3
DOIs
Publication statusPublished - 2020

Keywords

  • Cone-rod dystrophy
  • Genotype-phenotype
  • Histopathology
  • Natural history
  • Retinal dystrophies
  • Retinitis Pigmentosa GTPase Regulator (RPGR)
  • Retinitis pigmentosa

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