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Study of the Pathogenesis of Porphyria Cutanea Tarda

2014-08-27 03:58:02 | BioPortfolio

Summary

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.

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 Design

Primary Purpose: Screening

Conditions

Porphyria Cutanea Tarda

Location

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

Status

Completed

Source

National Center for Research Resources (NCRR)

Results (where available)

View Results

Links

Published on BioPortfolio: 2014-08-27T03:58:02-0400

Clinical Trials [9 Associated Clinical Trials listed on BioPortfolio]

Pilot Trial of Deferasirox in the Treatment of Porphyria Cutanea Tarda

To determine the efficacy and tolerability of deferasirox in the treatment of Porphyria Cutanea Tarda. Primary objective - the elimination of all blistering within 6 months of treatment. ...

Harvoni Treatment Porphyria Cutanea Tarda

In the medical literature there case reports that Harvoni improves symptoms in patients with PCT. However, this has never been systematically tested. Therefore, the purpose of this study i...

Studies in Porphyria I: Characterization of Enzyme Defects

OBJECTIVES: I. Characterize enzyme defects in patients with known or suspected porphyria and their family members. II. Determine whether selected patients are eligible for other porphyr...

EXPLORE: A Natural History Study of Acute Hepatic Porphyria (AHP)

The purpose of this study is to characterize the natural history and clinical management of Acute Hepatic Porphyria (AHP) patients with recurring attacks.

Studies in Porphyria IV: Gonadotropin-Releasing Hormone (GnRH) Analogues for Prevention of Cyclic Attacks

OBJECTIVES: Assess whether chronic administration of gonadotropin-releasing hormone analogues is safe and effective for the prevention of cyclic attacks of acute porphyria in women.

PubMed Articles [24 Associated PubMed Articles listed on BioPortfolio]

Genetic ancestry of patients with porphyria cutanea tarda in a country with mixed races: a cross-sectional study (Rio de Janeiro - Brazil).

Porphyria cutanea tarda has a complex etiology with genetic factors not completely elucidated. The miscegenation of the Brazilian population has important implications in the predisposition to disease...

Total Corneal Melt in Patient with Porphyria Cutanea Tarda in Presence of another Risk Factor.

To report a case of two siblings affected by porphyria cutanea tarda (PCT) presenting with varying severity of ocular disease and evaluation of difference in the presence of risk factors.

Resolution of porphyria cutanea tarda in HIV and mixed HCV coinfection after direct-acting antiviral (DAA) therapy.

Porphyria: What Is It and Who Should Be Evaluated?

The porphyrias are a group of rare metabolic disorders, inherited or acquired, along the heme biosynthetic pathway, which could manifest with neurovisceral and/or cutaneous symptoms, depending on the ...

Recombinant Hsp33 and OmpC protein can serve as promising divalent vaccine with protection against Vibrio anguillarum and Edwardsiella tarda in flounder (Paralichthys olivaceus).

Vibrio anguillarum and Edwardsiella tarda are severe aquaculture pathogens shared similar epidemiological characteristic and susceptible to flounder (Paralichthys olivaceus). In our previous studies, ...

Medical and Biotech [MESH] Definitions

An autosomal recessive cutaneous porphyria that is due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in both the LIVER and the BONE MARROW. Similar to PORPHYRIA CUTANEA TARDA, this disorder is caused by defects in the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME, but is a homozygous enzyme deficiency with less than 10% of the normal enzyme activity. Cutaneous lesions are severe and mutilating.

An enzyme that catalyzes the decarboxylation of UROPORPHYRINOGEN III to coproporphyrinogen III by the conversion of four acetate groups to four methyl groups. It is the fifth enzyme in the 8-enzyme biosynthetic pathway of HEME. Several forms of cutaneous PORPHYRIAS are results of this enzyme deficiency as in PORPHYRIA CUTANEA TARDA; and HEPATOERYTHROPOIETIC PORPHYRIA.

An autosomal dominant or acquired porphyria due to a deficiency of UROPORPHYRINOGEN DECARBOXYLASE in the LIVER. It is characterized by photosensitivity and cutaneous lesions with little or no neurologic symptoms. Type I is the acquired form and is strongly associated with liver diseases and hepatic toxicities caused by alcohol or estrogenic steroids. Type II is the familial form.

The techniques used to draw blood from a vein for diagnostic purposes or for treatment of certain blood disorders such as erythrocytosis, hemochromatosis, polycythemia vera, and porphyria cutanea tarda.

A group of metabolic diseases due to deficiency of one of a number of LIVER enzymes in the biosynthetic pathway of HEME. They are characterized by the accumulation and increased excretion of PORPHYRINS or its precursors. Clinical features include neurological symptoms (PORPHYRIA, ACUTE INTERMITTENT), cutaneous lesions due to photosensitivity (PORPHYRIA CUTANEA TARDA), or both (HEREDITARY COPROPORPHYRIA). Hepatic porphyrias can be hereditary or acquired as a result of toxicity to the hepatic tissues.

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