Scientists map rare blindness to speed future cures
NCT ID NCT04765345
First seen Jun 27, 2026 · Last updated Jun 27, 2026
Summary
This study follows 44 people with a rare genetic form of Usher syndrome caused by PCDH15 mutations. Over 48 months, researchers measure how their vision changes using eye exams and imaging. The goal is to identify the best ways to track disease progression, which will help design future clinical trials for potential treatments.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- What this could lead to
- If successful, this study could provide the key measurements needed to test new treatments for this rare form of blindness.
- What could go wrong
- This is an observational study, not a treatment trial. It only measures disease progression and does not test any therapy, so it cannot directly help participants.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Participants
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44 people
The number who actually took part.
- Started
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Jun 2021
- Expected to finish
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Jun 2027
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
Who is studied
Study participants will be recruited from approximately 10 clinical sites worldwide. All eligible participants will be included without regard to gender, race, or ethnicity. Potential eligibility will be assessed during a routine examination by an investigator prior to obtaining informed consent, as part of usual care, through referrals from other providers or self-referral.
- Ages
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8 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: Participants must meet all the following inclusion criteria at the Screening Visit in order to be eligible to enroll into the genetic screening phase. 1. Willing to participate in the study and able to communicate consent during the consent process 2. Ability to return for all study visits over 48 months 3. Age ≥ 8 years 4. Not planning to enroll in an experimental clinical trial for the treatment of PCDH15 for the duration of this study 5. Must meet one of the Genetic Screening Criteria, defined below: * Screening Group A: At least 2 disease-causing variants in the PCDH15 gene which are homozygous or heterozygous in trans, based on a report from a clinically certified lab (or a report from a research lab that has been pre- approved by the Genetics Committee) * Screening Group B: Only 1 disease-causing variant in the PCDH15 gene, based on a report from a clinically certified lab (or a report from a research lab which has been pre-approved by the Genetics Committee) * Screening Group C: At least 2 disease-causing variants in the PCDH15 gene which are unknown phase, based on a report from a clinically certified lab (or a report from a research lab which has been pre-approved by the Genetics Committee) Note pertaining to all Screening Groups: if a participant has a variant(s) of unknown significance, he/she would still qualify if there is at least 1 disease-causing variant(s) on the PCDH15 gene. The Genetics Committee will review unique cases where segregation analysis is not feasible to determine eligibility. Ocular Inclusion Criteria Both eyes must meet all the following at the Screening Visit for a participant to be eligible to enroll into the genetic screening phase. 1. Clinical diagnosis of retinal dystrophy 2. Clear ocular media and adequate pupil dilation to permit good quality photographic imaging Exclusion Criteria: Participants must not meet any of the following exclusion criteria at the Screening Visit in order to be eligible to enroll into the genetic screening phase. 1. Mutations in genes that cause autosomal dominant retinitis pigmentosa (ADRP), X-linked retinitis pigmentosa (RP), or presence of biallelic mutations in autosomal recessive RP/retinal dystrophy genes other than PCDH15 2. Expected to enter experimental treatment trial at any time during this study 3. History of more than 1 year of cumulative treatment, at any time, with an agent associated with pigmentary retinopathy (including hydroxychloroquine, chloroquine, thioridazine, and deferoxamine) Note: Pregnant women are not being specifically excluded from participation. Ocular Exclusion Criteria If either eye has any of the following at the Screening Visit, the participant is not eligible to enroll into the genetic screening phase. 1. Current vitreous hemorrhage 2. Current or any history of tractional or rhegmatogenous retinal detachment 3. Current or any history of (e.g., prior to cataract or refractive surgery) spherical equivalent of the refractive error worse than -8 Diopters of myopia 4. History of intraocular surgery (e.g., cataract surgery, vitrectomy, penetrating keratoplasty, or LASIK) within the last 3 months 5. Current or any history of confirmed diagnosis of glaucoma (e.g., based on glaucomatous VF changes or nerve changes, or history of glaucoma filtering surgery) 6. Current or any history of retinal vascular occlusion or proliferative diabetic retinopathy 7. History or current evidence of ocular disease that, in the opinion of the investigator, may confound assessment of visual function 8. History or evidence of active treatment for retinitis pigmentosa that could affect the progression of retinal degeneration, including: 1. Any use of ocular stem cell or gene therapy 2. Any treatment with ocriplasmin 3. Treatment with an ophthalmic oligonucleotide within the last 9 months (last treatment date is less than 9 months prior to Screening Visit date) 4. Treatment with any other product within five times the expected half-life of the product (time from last treatment date to Screening Visit date is at least 5 times the half-life of the given product) 5. Treatment with Ozurdex (dexamethasone), Iluvien or Yutiq (fluocinolone acetonide) intravitreal implant
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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CHNO des Quinze-Vingts
Paris, France
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Duke University, Duke Eye Center
Durham, North Carolina, 27710, United States
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Haddassah Medical Center
Jerusalem, Israel
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Hospital for Sick Children
Toronto, Ontario, Canada
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Moorfields Eye Hospital
London, EC1V 2PD, United Kingdom
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Radboud University
Nijmegen, Netherlands
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The Johns Hopkins Wilmer Eye Institute
Baltimore, Maryland, 21287, United States
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University Hospital Basel
Basel, 4031, Switzerland
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University of California, San Francisco
San Francisco, California, 94143-0344, United States
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University of Tubingen
Tübingen, Germany
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Can an eye injection slow a genetic cause of blindness?
- Can a single eye injection restore sight in genetic blindness?
- A sharper look at the retina: new imaging technology may spot eye disease earlier
- Stem cell eye transplant aims to halt blindness from rare genetic disease
- Could stem cells restore sight in damaged eyes?
- Gene therapy injection aims to restore sight in rare blindness