Erythropoietic Protoporphyrias: Studies of the Natural History, Genotype-Phenotype Correlations, and Psychosocial Impact

The porphyrias are a group of rare metabolic diseases that may present in childhood or adult life and are due to deficiencies of enzymes in the heme biosynthetic pathway. The most common manifestations are related to accumulation of intermediates in the pathway and usually occur as acute neurological attacks (as in the acute or hepatic porphyrias), or cutaneous photosensitivity (as in the cutaneous porphyrias, including the erythropoietic protoporphyrias). Multiple mutations have been identified in each of the porphyrias. The risk of disability or death from these disorders is significant, in part because diagnosis is often delayed due to lack of adoption of diagnostic testing in clinical practice. Moreover, the natural history of these disorders is not well described and it is not known what determines differences in outcomes. New therapies are needed. For existing therapies, high-quality evidence on short and long term efficacy and safety is generally lacking. Therefore, the purpose of this study of a large group of patients with EPP and XLP is to provide a better understanding of the natural history of these disorders, as affected by available therapies, and to aid in developing new forms of treatment. Much of the data collected on subjects as participants in the Longitudinal Study of the Porphyrias will be accessed for this study specific to the investigation of the erythropoietic protoporphyrias. To maximize the information that can be informative in our objectives, additional data will be collected, including additional biochemical findings and EPP-specific psychosocial parameters. The Office of Rare Diseases (ORD) of the National Institutes of Health (NIH) established a Rare Diseases Clinical Research Network (RDCRN) in collaboration with other NIH Institutes and currently has funded 19 rare diseases clinical research consortia and one Data Management and Coordinating Center. The Porphyrias Consortium was created as part of the RDCRN, to study the human porphyrias. The Porphyrias Consortium is a consortium of the academic institutions listed in the participating institutions table. All Centers in the Porphyrias Consortium are participating in this study. Additional centers may be added if funding is available.