CNGB1 and Allied Disorders

Study Overview
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Brief Summary
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Mutations in the rod-expressed gene, cyclic nucleotide-gated channel beta subunit (CNGB1) and associated inborn errors in metabolism are causes of retinal disease that causes progressive loss of vision. Retinitis pigmentosa (RP) is a major cause of untreatable blindness associated with CNGB1 (CNGB1-RP). RP involves the death of photoreceptor cells that can be caused by mutations in a number of different genes. Treatment by gene therapy could prevent blindness in cases of inherited retinal dystrophies including RP. In the future RP due to mutations in CNGB1 may be treatable by gene therapy since this form of photoreceptor degeneration involves a slow loss of rod photoreceptor cells. This provides a wide window of opportunity for the identification of patients and initiation of treatment. Our efforts are directed toward developing gene therapy as a treatment. To this end, our objective is to better understand the disease process of CNGB1-RP and other allied inherited disorders so that we can develop clinical tests to measure the outcomes of treatment.

Official Title
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Study of CNGB1 Retinitis Pigmentosa and Allied Hereditary Disorders

Conditions
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Retinitis Pigmentosa Associated With CNGB1 Mutations

Intervention / Treatment
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* Other: No intervention, this is a natural history progression study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of CNGB1-associated RP by study physician, who are trained retinal specialists in the university clinic Must be able to commit to 4 follow-up study visits (3 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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Arms and Interventions

| Intervention/Treatment |
| --- |
|Other: No intervention, this is a natural history progression study|The objective is to better understand the disease process of CNGB1-RP so that we can develop clinical tests to measure the outcomes of treatment.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| We will be looking to identify what the best outcome measurements will be for CNGB1-RP in order to use these measurements in a future clinical trial. | Both structural imaging and functional tests will be used to characterize the natural history progression of CNGB1-RP. | 2 days, 1 time per year, for 3 years | 
| Medmont Dark Adapted Chromatic (DAC) Automated Perimeter |  | 1 time per year, for 3 years | 
| Full-field ERG (ISCEV Protocol) |  | 1 time per year, for 3 years | 
| Optical Coherence Tomography (OCT) |  | 1 time per year, for 3 years | 
| Fundus Autofluorescence (FAF) |  | 1 time per year, for 3 years | 
| Near-infrared fundus autofluorescence (NIR-AF) |  | 1 time per year, for 3 years | 
| Quantitative Fundus Autofluorescence (qAF) |  | 1 time per year, for 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Best-corrected Visual Acuity (BCVA) |  | 1 time per year, for 3 years | 
| Complete Ophthalmic Exam |  | 2 time per year, for 3 years | 
| Color Fundus Photos |  | 1 time per year, for 3 years | 
| MAIA Microperimetry | if available | 1 time per year, for 3 years | 
| NIDEK Microperimetry | if available | 1 time per year, for 3 years | 
| Goldman Kinetic Visual Field |  | 1 time per year, for 3 years | 
| Light-adapted Static Perimetry |  | 1 time per year, for 3 years | 
| Panel D-15 Colour Vision (desat.) |  | 1 time per year, for 3 years | 
| Dark-adapted Chromatic Perimetry |  | 1 time per year, for 3 years | 
| Full-field Stimulus Testing (FST) | Optional | 1 time per year, for 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Retinitis Pigmentosa, CNGB1, Natural Progression