Porphyrias are rare metabolic disorders caused by decreased or increased activity of one of the nine enzymes involved in the heme biosynthetic pathway, resulting in the accumulation of porphyrins or their precursors. Although nine subtypes are currently recognized, substantial overlap in clinical manifestations often makes diagnosis challenging. This article presents the English version of the first national clinical practice guidelines for porphyrias in Japan, originally published in 2025 by the Japanese Dermatological Association. The guidelines were developed by the Clinical Practice Guideline Committee, established as part of the Research Project on Intractable Diseases of the Ministry of Health, Labour and Welfare of Japan. Diagnostic and severity assessment criteria were based on those proposed by the Ministry research group. Clinical questions (CQs) were formulated, and recommendations were developed according to the principles of evidence-based medicine, incorporating both domestic and international evidence. The guidelines provide diagnostic criteria, severity classification, and evidence-based recommendations for the management of porphyrias. Although causative genes have been identified, the pathophysiology remains incompletely understood, and no curative therapy is currently available, and liver transplantation may be required in severe cases with liver failure. These guidelines aim to provide practical guidance for clinicians managing porphyrias in Japan. Future revisions will be necessary in response to advances in diagnostic technologies and therapeutic strategies.
Shimizu et al. (Sun,) studied this question.