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Study of the Pathogenesis of Porphyria Cutanea Tarda

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00005103
First Posted: April 7, 2000
Last Update Posted: December 9, 2005
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Collaborator:
University of Texas
Information provided by:
National Center for Research Resources (NCRR)
April 6, 2000
April 7, 2000
December 9, 2005
November 2000
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No Changes Posted
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Study of the Pathogenesis of Porphyria Cutanea Tarda
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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.

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.

Observational
Primary Purpose: Screening
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Porphyria Cutanea Tarda
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*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Completed
120
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  • 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
Sexes Eligible for Study: All
Child, Adult, Senior
No
Contact information is only displayed when the study is recruiting subjects
United States
 
 
NCT00005103
199/14875
UTMB-433
UTMB-95-173
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National Center for Research Resources (NCRR)
University of Texas
Study Chair: Karl Elmo Anderson University of Texas
National Center for Research Resources (NCRR)
December 2003