Natural History Study of Patients With X-linked Retinal Dystrophy Associated With Mutations in Retinitis Pigmentosa GTPase Regulator (RPGR)


The rod-cone dystrophies (often referred to as retinitis pigmentosa (RP)) are a clinically and genetically heterogeneous group of disorders in which there is progressive loss of rod and later cone photoreceptor function leading to severe visual impairment. RP usually occurs as an isolated retinal disorder, but it may also be seen in association with systemic abnormalities.

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: December 30, 2022

Detailed Description

X-linked Retinitis Pigmentosa (XLRP) is a severe form of RP with early onset of nyctalopia and progression to legal blindness by the 3rd to 4th decade. Most affected males show symptomatic night blindness before the age of 10 years, are often myopic and show fundus abnormalities and ERG changes in early childhood. Examination of close female relatives is helpful in the absence of a family history, as the recognition of the XL carrier state will confirm the diagnosis.

Clinical Trial Outcome Measures

Primary Measures

  • Analysis of retinal structure and function to assess disease progression
    • Time Frame: 6 years
    • Retinal structure will be measured using Adaptive optics and SD-OCT and Fundal autofluorescence.

Secondary Measures

  • Retinal Sensitivity
    • Time Frame: 6 years
    • To be assessed by Microperimetry
  • Retinal Structural detailed phenotyping
    • Time Frame: 6 years
    • Retinal Structure measured by Adaptive Optics (
  • Fundus Autofluorescence
    • Time Frame: 6 years
    • Presence or Absence
  • Visual Fields testing
    • Time Frame: 6 years
    • Assessment of Visual Fields with analysis of hill vision by perimetry

Participating in This Clinical Trial

Inclusion Criteria

  • Males & Females aged 5 years or older – Have RPGR-associated retinal dystrophy – Are able to give informed consent or assent, with the guidance of their parent/guardian where appropriate – Are able to undertake age-appropriate clinical assessments as specified in the protocol – Have genetic mutation within the RPGR gene confirmed by an accredited lab or research lab. Exclusion Criteria:

  • Are unable or unwilling to undertake consent or clinical testing

Gender Eligibility: All

Minimum Age: 5 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • MeiraGTx UK II Ltd
  • Collaborator
    • Janssen, LP
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Michel Michaelides, Prof, Principal Investigator, UCL/Moorfields
  • Overall Contact(s)
    • MeiraGTx UK II Ltd, +44 (0) 20 3866 4320,

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