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

Study Overview
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Brief Summary
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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
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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.

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

Conditions
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Retinitis Pigmentosa

Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

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

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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retinitis pigmentosa, PDE6A, gene therapy trial