You are viewing an expired study

This study is not currently recruiting Study Participants on If you would like to find active studies please browse nearby listings below.

Click here to view additional nearby studies or search for clinical trials.

Portland, Oregon 97201

  • Retinitis Pigmentosa


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.

Study summary:

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.


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



Primary Contact:

Study Chair
William Connor
Oregon Health and Science University

Backup Contact:


Location Contact:

Portland, Oregon 97201
United States

There is no listed contact information for this specific location.

Site Status: N/A

Data Source:

Date Processed: April 03, 2020

Modifications to this listing: Only selected fields are shown, please use the link below to view all information about this clinical trial.

Click to view Full Listing

This study is not currently recruiting Study Participants on The form below is not enabled.