Clinical Characterization on PDE6A-related Retinitis Pigmentosa in Preparation to a Gene Therapy Trial

Clinical Characterization on PDE6A-related Retinitis Pigmentosa in Preparation to a Gene Therapy Trial: An Observational Study

Mutations in the PDE6A gene - encoding the -subunit of the rod cGMP-phosphodiesterase - account for 1% of autosomal recessive retinitis pigmentosa (arRP) through impaired regulation of cGMP levels in the rod outer segment. This study aims for a detailed clinical characterization of patients with PDE6A mutations in preparation of a clinical gene replacement study (phase I/II safety trial).

Study Overview

• Status: Completed
• Conditions: Retinitis Pigmentosa

Detailed Description

Retinitis pigmentosa (RP) is a clinically and genetically heterogenous group of hereditary retinal disorders, being one of the most common types of retinal degenerations with a prevalence of 1:4000. More than 45 genes have been associated with RP so far, whose defects cause a progressive loss of rod photoreceptor function, followed by cone photoreceptor dysfunction often leading to complete blindness. Mutations in the PDE6A gene - encoding the -subunit of the rod cGMP-phosphodiesterase - account for 1% of autosomal recessive retinitis pigmentosa (arRP) through impaired regulation of cGMP levels in the rod outer segment.

With the help of improved genetic and functional diagnostic tools an early recognition and differentiation has become possible. Still, up to date no established therapy is available, therefore, social and professional consequences are essential tasks to deal with. The modern ophthalmological functional diagnostic tools enable a precise characterisation and early recognition of such retinal diseases. The detailed results and information can help to extend the understanding of the pathological mechanisms involved in these diseases.

In this study the investigators intend to investigate patients with a genetically confirmed diagnosis of Retinitis pigmentosa due to PDE6A mutations hereby assessing the function and structure of the retina with an extensive battery of tests.

• Study Type: Observational
• Enrollment (Estimated): 50

Contacts and Locations

Study Locations

• Germany
  • Baden-Württemberg
    • Tübingen, Baden-Württemberg, Germany, 72076
      • Institute for Ophthalmic Research, University Tübingen, Germany

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 80 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

• Sampling Method: Probability Sample

Study Population

Retinitis pigmentosa patients with genetically confirmed mutations in the PDE6A-gene

Description

Inclusion Criteria:

• Retinitis pigmentosa patients with genetically confirmed mutations in the PDE6A-gene
• written informed consent

Exclusion Criteria:

• severe general disease, that would make longer examinations not possible
• patients who cannot give written informed consent independently

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
best corrected visual acuity in both eyes	3 years
kinetic visual field in both eyes	3 years
central retinal thickness in both eyes	3 years

Secondary Outcome Measures

Outcome Measure	Time Frame
multifocal ERG responses in both eyes	3 years
colour vision in both eyes	3 years

Collaborators and Investigators

• Sponsor: STZ eyetrial
• Investigators: Principal Investigator: Ditta Zobor, MD, PhD, Institute for Ophthalmic Research, University Tübingen, Germany; Principal Investigator: Susanne Kohl, PhD, Institute for Ophthalmic Research, University Tübingen, Germany

Study record dates

Study Major Dates

• Study Start: January 1, 2013
• Primary Completion (Actual): May 1, 2025
• Study Completion (Actual): May 1, 2025

Study Registration Dates

• First Submitted: April 25, 2016
• First Submitted That Met QC Criteria: April 28, 2016
• First Posted (Estimated): May 3, 2016

Study Record Updates

• Last Update Posted (Actual): May 18, 2025
• Last Update Submitted That Met QC Criteria: May 14, 2025
• Last Verified: May 1, 2025

More Information

Terms related to this study

• Keywords: retinitis pigmentosa; PDE6A; gene therapy trial
• Additional Relevant MeSH Terms: Genetic Diseases, Inborn; Eye Diseases; Eye Diseases, Hereditary; Retinal Diseases; Retinal Dystrophies; Retinal Degeneration; Retinitis; Retinitis Pigmentosa
• Other Study ID Numbers: RDC-PDE6A-00

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No