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

Completed

• Conditions: Retinitis Pigmentosa

• Registration Number: NCT02759952
• Lead Sponsor: STZ eyetrial

Brief Summary

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).

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 Timeline

• Study Start: 2013-01
• Study First Submitted: 2016-04-25
• Study First Submitted QC: 2016-04-28
• Study First Posted: 2016-05-03
• Status Verified: 2025-05
• Primary Completion: 2025-05
• Study Completion: 2025-05
• Last Update Submitted: 2025-05-14
• Last Update Posted: 2025-05-18

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 50

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 & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
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

Name	Time	Method
multifocal ERG responses in both eyes	3 years
colour vision in both eyes	3 years

Trial Locations

Locations (1)

Institute for Ophthalmic Research, University Tübingen, Germany; 🇩🇪 Tübingen, Baden-Württemberg, Germany