Usher SyndromeNCT00004345
Study of Dietary N-3 Fatty Acids in Patients With Retinitis Pigmentosa and Usher Syndrome
An observational study of Usher Syndrome and Retinitis Pigmentosa, run by National Center for Research Resources (NCRR) at 1 site in United States.
Trial summary
OBJECTIVES: I. Examine the concentration of docosahexanoic acid (DHA) and other n-3 fatty acids in plasma, erythrocyte, and adipose tissue in patients with various forms of retinitis pigmentosa and Usher syndrome. II. Determine the synthesis and catabolism of DHA from linolenic acid in these patients. III. Read more about this study
- Who is it for?
- Ages 0 years and olderHealthy volunteers can take part
- Conditions the study is for
- Usher Syndrome, Retinitis Pigmentosa
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- Oct 1999to not given
- 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 0 years and older
- All sexes
- Healthy volunteers accepted
- Child, Adult, Older adult
PROTOCOL ENTRY CRITERIA:
- Retinitis pigmentosa, including: Usher syndrome (types I and II) Simplex
- The following inheritance patterns eligible: X-linked recessive; Autosomal dominant; Autosomal recessive
Trial locations and contacts
1 site in 1 country.
United States1 site
Oregon Health Sciences University
Portland, Oregon, 97201-3098
About this study
OBJECTIVES: I. Examine the concentration of docosahexanoic acid (DHA) and other n-3 fatty acids in plasma, erythrocyte, and adipose tissue in patients with various forms of retinitis pigmentosa and Usher syndrome.
II. Determine the synthesis and catabolism of DHA from linolenic acid in these patients.
III. Determine the synthesis, absorption, and catabolism of DHA under different dietary conditions in these patients.
Read the detailed description
PROTOCOL OUTLINE: Patients may participate in one or more of the arms of this study.
Arm I (adipose tissue study): Adipose tissue is collected from the buttocks of patients with Usher II retinitis pigmentosa (RP), patients with non-Usher RP, and control subjects. Dietary histories are obtained from all patients and subjects.
Arm II (isotope study): Patients meeting the same criteria as in arm I receive oral D5-labeled linolenic acid and oral D4-labeled linolenic acid that is dissolved in oil and incorporated into foods. Subjects must avoid eating fish and shellfish during the 35 days of the isotope study. Blood samples are collected at 0, 8, 24, and 48 hours, daily on days 3-7, and then on days 10, 18, and 35.
Arm III (flaxseed oil feeding): Patients with all types of RP and control subjects receive flaxseed oil, a form of linolenic acid, for 12 weeks. Subjects may also receive high oleic safflower oil or olive oil as a control fat for 12 weeks. Subjects complete a diet history at the end of each fatty acid supplementation period. All subjects must follow a diet free of seafood and fish oil supplements.
- Conditions
- Usher Syndrome, Retinitis Pigmentosa
- Keywords
- Usher syndrome, ophthalmologic disorders, rare disease, retinitis pigmentosa
- Medical subject headings
- Usher Syndromes, Retinitis Pigmentosa, Rare Diseases
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted19 Oct 1999 (estimated)
- Study startOct 1999
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Usher SyndromeStudies of the same condition, open and under way.
- 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
- Enrolment
- 100 participants
Sponsor and investigators
- Lead sponsor
- National Center for Research Resources (NCRR)
- Sponsor type
- US National Institutes of Health
- Collaborators
- Oregon Health and Science University
- Investigators
- William Connor, Study chair, Oregon Health and Science University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00004345
- Sponsor's protocol ID
- 199/11904
- Other IDs
- OHSU-2650
- Status last verified
- Jul 2002
- First submitted
- 18 Oct 1999
- Last updated
- 24 Jun 2005
- Results posted
- No
Publications
Schwartz SG, Wang X, Chavis P, Kuriyan AE, Abariga SA. Vitamin A and fish oils for preventing the progression of retinitis pigmentosa. Cochrane Database Syst Rev. 2020 Jun 18;6(6):CD008428. doi: 10.1002/14651858.CD008428.pub3.
PubMed 32573764
Study at a glance
From the registry record, last updated by the sponsor on 24 Jun 2005. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Study of Dietary N-3 Fatty Acids in Patients With Retinitis Pigmentosa and Usher Syndrome
- ClinicalTrials.gov ID
- NCT00004345
- Acronym / sponsor ID
- 199/11904
- Conditions
- Usher Syndrome, Retinitis Pigmentosa
- Keywords
- Usher syndrome, ophthalmologic disorders, rare disease, retinitis pigmentosa
- Study type
- Observational
- Recruitment status
- Terminated
- Enrolment
- 100 participants
- Lead sponsor
- National Center for Research Resources (NCRR)US National Institutes of Health
- Collaborators
- Oregon Health and Science University
- Study start
- Oct 1999
- First posted
- 19 Oct 1999 (estimated)
- 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.
OBJECTIVES: I. Examine the concentration of docosahexanoic acid (DHA) and other n-3 fatty acids in plasma, erythrocyte, and adipose tissue in patients with various forms of retinitis pigmentosa and Usher syndrome.
II. Determine the synthesis and catabolism of DHA from linolenic acid in these patients.
III. Determine the synthesis, absorption, and catabolism of DHA under different dietary conditions in these patients.
Detailed description
PROTOCOL OUTLINE: Patients may participate in one or more of the arms of this study.
Arm I (adipose tissue study): Adipose tissue is collected from the buttocks of patients with Usher II retinitis pigmentosa (RP), patients with non-Usher RP, and control subjects. Dietary histories are obtained from all patients and subjects.
Arm II (isotope study): Patients meeting the same criteria as in arm I receive oral D5-labeled linolenic acid and oral D4-labeled linolenic acid that is dissolved in oil and incorporated into foods. Subjects must avoid eating fish and shellfish during the 35 days of the isotope study. Blood samples are collected at 0, 8, 24, and 48 hours, daily on days 3-7, and then on days 10, 18, and 35.
Arm III (flaxseed oil feeding): Patients with all types of RP and control subjects receive flaxseed oil, a form of linolenic acid, for 12 weeks. Subjects may also receive high oleic safflower oil or olive oil as a control fat for 12 weeks. Subjects complete a diet history at the end of each fatty acid supplementation period. All subjects must follow a diet free of seafood and fish oil supplements.
Study design
Who may qualify
- Ages
- 0 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study was stopped early. Results are not available in the source record.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Jun 2005.
- Derived from this study: PubMed 32573764Schwartz SG, Wang X, Chavis P, Kuriyan AE, Abariga SA. Vitamin A and fish oils for preventing the progression of retinitis pigmentosa. Cochrane Database Syst Rev. 2020 Jun 18;6(6):CD008428. doi: 10.1002/14651858.CD008428.pub3.
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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.
William Connor study chair
Oregon Health and Science University
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 Usher Syndrome and Retinitis Pigmentosa, run by National Center for Research Resources (NCRR) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
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 24 Jun 2005. 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 United States. 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. 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.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00004345, which also lists 1 linked publication.
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 24 Jun 2005.