Erythropoietic protoporphyrias: Pathogenesis, diagnosis and management.
Study Goal
The researchers aimed to assess the role of Vitamin D supplementation in managing complications like deficiency and reduced bone mineral density in patients with erythropoietic protoporphyrias.
Results Summary
The study found that Vitamin D deficiency is a complication in erythropoietic protoporphyrias and recommended supplementation to address this issue, along with considering DEXA scans in adults.
Population
Patients with erythropoietic protoporphyrias (EPP1, XLEPP, EPP2).
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Vitamin D supplementation | increase | vitamin D deficiency | patients with erythropoietic protoporphyrias | - | should be supplemented | #1 |
iron supplementation | increase | photosensitivity | patients with EPP1 with biochemically determined iron deficiency | - | may stimulate PPIX production, resulting in an increase | #2 |
iron supplementation | increase | risk of cholestatic liver disease | patients with EPP1 with biochemically determined iron deficiency | - | may stimulate PPIX production, resulting in an increase | #3 |
iron supplementation | decrease | PPIX levels | patients with XLEPP | - | can reduce | #4 |
iron supplementation | decrease | phototoxicity | patients with XLEPP | - | can reduce | #5 |
iron supplementation | decrease | liver damage | patients with XLEPP | - | can reduce | #6 |
Afamelanotide | increase | pain-free sunlight exposure | patients with erythropoietic protoporphyrias | - | increases | #7 |
Afamelanotide | increase | quality of life | patients with erythropoietic protoporphyrias | - | increases | #8 |
The erythropoietic protoporphyrias consist of three ultra-rare genetic disorders of the erythroid heme biosynthesis, including erythropoietic protoporphyria (EPP1), X-linked protoporphyria (XLEPP) and CLPX-protoporphyria (EPP2), which all lead to the accumulation of protoporphyrin IX (PPIX) in erythrocytes. Affected patients usually present from early childhood with episodes of severe phototoxic pain in the skin exposed to visible light. The quantification of PPIX in erythrocytes with a metal-free PPIX ≥3 times the upper limit of normal confirms the diagnosis. Protoporphyria-related complications include liver failure, gallstones, mild anaemia and vitamin D deficiency with reduced bone mineral density. The management is focused on preventing phototoxic reactions and treating the complications. Vitamin D should be supplemented, and DEXA scans in adults should be considered. In EPP1, even in cases of biochemically determined iron deficiency, supplementation of iron may stimulate PPIX production, resulting in an increase in photosensitivity and the risk of cholestatic liver disease. However, for patients with XLEPP, iron supplementation can reduce PPIX levels, phototoxicity and liver damage. Because of its rarity, there is little data on the management of EPP-related liver disease. As a first measure, any hepatotoxins should be eliminated. Depending on the severity of the liver disease, phlebotomies, exchange transfusions and ultimately liver transplantation with subsequent haematopoietic stem cell transplantation (HSCT) are therapeutic options, whereby multidisciplinary management including porphyria experts is mandatory. Afamelanotide, an alpha-melanocyte-stimulating hormone analogue, is currently the only approved specific treatment that increases pain-free sunlight exposure and quality of life.