Study of the Pathogenesis of Porphyria Cutanea Tarda

June 23, 2005 updated by: National Center for Research Resources (NCRR)

OBJECTIVES: I. Determine the effect of standard treatments on various predisposing factors in patients with porphyria cutanea tarda (PCT).

II. Investigate alcohol history, smoking, liver dysfunction and its etiology, estrogen use, and family history of PCT in these patients.

III. Study the relationships of excess iron and the hemochromatosis gene to PCT, including clinical features and risk of recurrence in these patients.

IV. Assess hepatitis C virus infections in these patients. V. Assess vitamin C levels in these patients before and after treatment. VI. Assess dietary habits in these patients. VII. Assess activity of cytochrome P450 enzymes (CYP) in vivo in these patients.

VIII. Study polymorphic genes for enzymes that metabolize foreign chemicals, including CYP enzymes and glutathione transferases in these patients.

Study Overview

Status

Completed

Conditions

Detailed Description

PROTOCOL OUTLINE: Patients undergo a complete medical evaluation and documentation of porphyria cutanea tarda (PCT) including history, physical examination, standard clinical laboratory tests and porphyrin studies. Alcohol history, smoking, liver dysfunction and its etiology, estrogen use, and family history of PCT are investigated and recorded. Patients complete a questionnaire to assess intake of vitamin C and other nutrients.

Iron status is assessed by serum ferritin, Fe and Fe binding capacity, and by the number of phlebotomies needed to reduce ferritin to the target level. A blood sample is tested for the hemochromatosis (HC) gene to determine whether each patient has 0, 1, or 2 copies of the HC mutation.

Serum hepatitis C virus (HCV) antibody and HCV RNA are measured. Standard liver function tests and liver biopsy are done if clinically indicated.

A fasting blood level of ascorbic acid is obtained. Blood clearance of caffeine and antipyrine, and urinary excretion of caffeine and chlorzoxazone metabolites are determined by breath tests or measurements in blood or saliva.

Genotyping for polymorphic genes for enzymes that metabolize foreign chemicals, including cytochrome P450 enzymes (CYP) and glutathione transferases are completed.

Following completion of the above studies, patients undergo individualized standard treatment either by serial phlebotomies or low dose chloroquine. Patients with HCV are also treated with interferon alfa-2b.

Patients are followed after treatment, at which time initial studies are repeated.

Study Type

Observational

Enrollment

120

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Texas
      • Galveston, Texas, United States, 77555-0209
        • University of Texas Medical Branch

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

1 year and older (Child, Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

  • Well documented sporadic (Type I) or familial (Type II) porphyria cutanea tarda: Increased plasma porphyrins (fluorescence maximum at neutral pH near 617 nm) Increased urinary porphyrins (consisting mostly of uroporphyrin and heptacarboxylporphyrin) Increased isocoproporphyrins in feces
  • No other type of porphyria

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Center for Research Resources (NCRR)

Collaborators

University of Texas

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2000

Study Registration Dates

First Submitted

April 6, 2000

First Submitted That Met QC Criteria

April 6, 2000

First Posted (Estimate)

April 7, 2000

Study Record Updates

Last Update Posted (Estimate)

June 24, 2005

Last Update Submitted That Met QC Criteria

June 23, 2005

Last Verified

December 1, 2003

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 199/14875
  • UTMB-433
  • UTMB-95-173

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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