Retinal Dystrophy, Cone-RodINTROCONENCT04658251
Study of New Mutations in Cone Disorders
An observational study of Retinal Dystrophy, Cone-Rod and Cone Dystrophy, run by University Hospital, Lille at 1 site in France.
Trial summary
High throughput sequencing gives the opportunity to improve the genetic diagnosis for patients suffering from retinal dystrophies and specially from cone disorders. However, a large number of mutations are identified, mostly in introns of the genes, and in silico analysis are not sufficient to assign the pathogenicity… Read more about this study
- Who is it for?
- Ages 3 years and older
- Conditions the study is for
- Retinal Dystrophy, Cone-Rod, Cone Dystrophy, Cone Rod Dystrophy
- What is being tested?
- Blood and/or skin biopsy
- How many people
- 7 participants
- Where
- 1 siteFrance
- Study dates
- 3 Mar 2021to 14 Apr 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 3 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Study population: Patients carrying an intronic variant of unknown significance (or carrying an exonic variant with a predicted effect on splicing) in a gene implicated (or potentially implicated) in cone disorders, will be included in the study.
Who may be able to join
- clinical diagnosis of cone disorder
- identification of a variant of unknown significance
- possibility of samplings
- informed consent
Who cannot join
- no variant of unknown significance identified
- no informed consent
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Functional Study of Intronic Variants in Inherited Cone Disorders
High throughput sequencing gives the opportunity to improve the genetic diagnosis for patients suffering from retinal dystrophies and specially from cone disorders. However, a large number of mutations are identified, mostly in introns of the genes, and in silico analysis are not sufficient to assign the pathogenicity of these mutations, without which the diagnosis confirmation cannot be done. For that purpose, a functional analysis of intronic variants of unknown significance detected in patients, with minigene splice assays in parallel with the analysis of the effect of the variant on splicing directly in the cells of the patient, by analyzing the RNA from leucocytes, fibroblasts, lymphoblastoïd cells or precursor of photoreceptor cells, which is the only proof of pathogenicity for variants
- Being tested
- Blood and/or skin biopsy
- Keywords
- intronic variant, splicing, functional test, cone disorders, retinal dystrophy, RNA, minigene splice assay, cells
- Medical subject headings
- Cone-Rod Dystrophies, Cone Dystrophy, Macular Degeneration, Retinal Dystrophies
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Blood and/or skin biopsyGenetic
Blood and/or skin biopsy will be withdrawn, for RNA extraction in order to test the effect of the variant on splicing.
| Study group | Role | What they receive |
|---|---|---|
| Patients with an intronic variant unknown in a gene implicated in cone disorders. | Not described Receives: Genetic: Blood and/or skin biopsy |
What is being measured
The primary outcome is the main question the study is designed to answer.
Effect of the intronic variant on RNA splicing observed in cellulo and/or on patient cells,
Analysis of RNA transcripts of the gene carrying a variant of unknown significance.
Measured: at 2 years
Secondary outcomes (5)
Effect of the intronic variant on RNA by Minigene splice assay in transient cell cultures
Measured: at 2 years
Effect of the intronic variant on RNA by analysis of patient RNA transcripts
Measured: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from fibroblasts
Measured: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from lymphoblastoid lines
Measured: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from IPSCs (induced pluripotent stem cells)
Measured: at 2 years
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Dec 2020
- Study start3 Mar 2021
- Primary completion14 Apr 2024
- Study completion14 Apr 2024
Why it stopped: End of COVID
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Retinal Dystrophy, Cone-RodStudies of the same condition, open and under way.
- More trials run by University Hospital, LilleThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 7 participants (actual)
Sponsor and investigators
- Lead sponsor
- University Hospital, Lille
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Claire-Marie DHAENENS, MD, Principal investigator, University Hospital, Lille
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04658251
- Sponsor's protocol ID
- 2020_66
- Other IDs
- 2020-A02559-30
- Acronym
- INTROCONE
- Status last verified
- May 2026
- First submitted
- 1 Dec 2020
- Last updated
- 22 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Functional Study of Intronic Variants in Inherited Cone Disorders
- ClinicalTrials.gov ID
- NCT04658251
- Acronym / sponsor ID
- INTROCONE / 2020_66
- Keywords
- intronic variant, splicing, functional test, cone disorders, retinal dystrophy, RNA, minigene splice assay, cells
- Study type
- Observational
- Recruitment status
- TerminatedReason stopped: End of COVID
- Enrolment
- 7 participants (actual)
- Lead sponsor
- University Hospital, LilleUniversity, hospital or other
- Study start
- 3 Mar 2021 (actual)
- Primary completion
- 14 Apr 2024 (actual)
- Study completion
- 14 Apr 2024 (actual)
- First posted
- 8 Dec 2020 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
High throughput sequencing gives the opportunity to improve the genetic diagnosis for patients suffering from retinal dystrophies and specially from cone disorders. However, a large number of mutations are identified, mostly in introns of the genes, and in silico analysis are not sufficient to assign the pathogenicity of these mutations, without which the diagnosis confirmation cannot be done. For that purpose, a functional analysis of intronic variants of unknown significance detected in patients, with minigene splice assays in parallel with the analysis of the effect of the variant on splicing directly in the cells of the patient, by analyzing the RNA from leucocytes, fibroblasts, lymphoblastoïd cells or precursor of photoreceptor cells, which is the only proof of pathogenicity for variants
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients with an intronic variant unknown in a gene implicated in cone disorders. | – | Genetic: Blood and/or skin biopsy |
Who may qualify
- Ages
- 3 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
- Study population
- Patients carrying an intronic variant of unknown significance (or carrying an exonic variant with a predicted effect on splicing) in a gene implicated (or potentially implicated) in cone disorders, will be included in the study.
Key inclusion criteria (4 listed)
- clinical diagnosis of cone disorder
- identification of a variant of unknown significance
- possibility of samplings
- informed consent
Key exclusion criteria (2 listed)
- no variant of unknown significance identified
- no informed consent
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Blood and/or skin biopsyBlood and/or skin biopsy will be withdrawn, for RNA extraction in order to test the effect of the variant on splicing. | Genetic | Patients with an intronic variant unknown in a gene implicated in cone disorders. |
Primary outcome
Effect of the intronic variant on RNA splicing observed in cellulo and/or on patient cells,
Time frame: at 2 years
Analysis of RNA transcripts of the gene carrying a variant of unknown significance.
5 secondary outcomes
Effect of the intronic variant on RNA by Minigene splice assay in transient cell cultures
Time frame: at 2 years
Effect of the intronic variant on RNA by analysis of patient RNA transcripts
Time frame: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from fibroblasts
Time frame: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from lymphoblastoid lines
Time frame: at 2 years
Effect of the intronic variant on RNA by analysis of transcripts from IPSCs (induced pluripotent stem cells)
Time frame: at 2 years
Results and safety
The study was stopped early (reason given: End of COVID). Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 May 2026.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Claire-Marie DHAENENS, MD principal investigator
University Hospital, Lille
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Retinal Dystrophy, Cone-Rod and Cone Dystrophy, run by University Hospital, Lille at 1 site in France.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 2 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: stopped early, as of the sponsor's last update on 22 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in France. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study was stopped early (reason given: End of COVID). Results are not available in the source record.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Effect of the intronic variant on RNA splicing observed in cellulo and/or on patient cells, (time frame: at 2 years). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 May 2026; AzTrials last refreshed its copy on 3 Nov 2026.