{
  "abstract": "Background Female carriers of X-linked conditions display a spectrum of disease, often attributed to skewed X-inactivation during embryogenesis. Herein, we describe the phenotype in a female carrier of c.3308_3309delAT (p.Tyr1103Serfs*7) – a frameshift variant in the basic domain of RPGR, which is associated with X-linked cone dystrophy in hemizygous males.Methods Retrospective review of ophthalmic examination results, multimodal retinal imaging and functional testing was conducted.Results A 71-year-old female was examined due to a diagnosis of RPGR-related cone dystrophy in her son. Visual acuities were clinically normal at 6/6, and refractive error measured -6.50/-2.00x15 and -6.00/-1.50x130 in the right and left eye, respectively. Slit-lamp examination was unremarkable. Retinal imaging showed mild foveal hyper-reflectance with green reflectance (518nm) which colocalised with a hyperreflective outer retinal band observed on SD-OCT. Fundus autofluorescence and ultra-widefield imaging showed no peripheral abnormalities. Cone-mediated mesopic microperimetry revealed a mosaic pattern of reduced macular sensitivity despite normal retinal structure on clinical imaging. Handheld electroretinography measured normal rod responses, while cone responses averaged 71.4% of the lower normal limit, compared to 36% in the male proband. This finding corroborates the stochastic nature of X-inactivation.Conclusion This case identifies a phenotype consistent with mild cone dysfunction and anatomical changes. Improved understanding of disease manifestations in female carriers is essential to identify affected individuals who may benefit from future gene-targeted therapies.",
  "authors": [
    {
      "affiliations": [
        "Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK",
        "Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK"
      ],
      "name": "Shabnam Raji"
    },
    {
      "affiliations": [
        "Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK",
        "Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK"
      ],
      "name": "Robert E MacLaren"
    },
    {
      "affiliations": [
        "Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK",
        "Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK",
        "Technical University of Munich, School of Medicine and Health, Department of Ophthalmology, TUM University Hospital, Munich, Germany"
      ],
      "name": "Peter Charbel Issa"
    },
    {
      "affiliations": [
        "Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK",
        "Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK"
      ],
      "name": "Jasmina Cehajic-Kapetanovic"
    }
  ],
  "title": "#CC-Paper-01 Clinical and electrophysiological profile in a female carrier of the c.3308_3309delAT (p.Tyr1103Serfs*7) RPGR variant associated with X-linked cone dystrophy",
  "uid": "30ae5189-ee55-53ff-b768-9728ba50927c"
}