Acute Porphyria Biomarkers for Disease Activity

This translational pilot research is based on preliminary results using animal models. The investigators will collect samples of blood, urine and feces from up to 50 participants with well documented acute porphyrias, at 2 expert sites that are members of the Porphyrias Consortium. Collection and analysis of these samples will be used to assess feasibility of performing such studies in humans with acute porphyrias, recognizing that these disorders are more heterogeneous than reproduced in animal models, and affect individuals who cannot all be studied simultaneously and in large groups. Therefore, we will assess the feasibility of methods for collecting, processing, storing and shipping samples at multiple study sites for later biomarker analysis. Larger and more definitive studies of biomarkers will be designed and implemented based on data and experience from this pilot-feasibility study.

Inclusion criteria

• Documented diagnosis of acute porphyria.

• For AIP: Elevation in urine PBG, with normal or only slight increases in plasma and fecal porphyrins. Most (~90%) will have deficient activity of erythrocyte PBGD.
• For HCP: Elevation in urine PBG, with substantial increases in fecal porphyrins (almost entirely coproporphyrin III). In the absence of skin photosensitivity, most will have normal or only slight increases in plasma porphyrins.
• For VP: Elevation in PBG, with substantial increases in fecal porphyrins (mostly coproporphyrin III and protoporphyrin), increased plasma total porphyrins and a fluorescence emission maximum of diluted plasma at neutral pH near 626 nm.

Exclusion criteria

• Another medical condition that might confound the results, as judged by the investigator