Study of Dietary N-3 Fatty Acids in Patients With Retinitis Pigmentosa and Usher Syndrome

Brief Title

Study of Dietary N-3 Fatty Acids in Patients With Retinitis Pigmentosa and Usher Syndrome

Brief 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. 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 Type



Usher Syndrome


* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information

Estimated Enrollment


Start Date

October 1999

Eligibility Criteria


          -  Retinitis pigmentosa, including: Usher syndrome (types I and II) Simplex

          -  The following inheritance patterns eligible: X-linked recessive; Autosomal dominant;
             Autosomal recessive




0 Years - 0 Years

Accepts Healthy Volunteers

Accepts Healthy Volunteers


William Connor, , 

Location Countries

United States

Location Countries

United States

Administrative Informations



Organization ID


Secondary IDs


Study Sponsor

National Center for Research Resources (NCRR)


 Oregon Health and Science University

Study Sponsor

William Connor, Study Chair, Oregon Health and Science University

Verification Date

July 2002