Erythropoietic protoporphyria (EPP) and X-linked protoporphyria are metabolic disorders that cause skin phototoxicity and potential liver damage. We compared symptoms and impacts of phototoxic reactions, health-related quality of life, and healthcare utilization (HCU) between individuals with and without self-reported liver disease (elevated liver enzymes or liver fibrosis) using an online questionnaire containing validated patient-reported outcome measures and original items. Among 164 participants, 15.2% self-reported liver disease. Sixty-four percent of those with liver disease rated their general health "much worse" than those without EPP, versus 35% of those without liver disease. Those with liver disease had a higher frequency of prodromal symptoms and more frequently reported that their most recent phototoxic reaction impacted their ability to perform daily activities (76% versus 55% for those without liver disease) and resulted in difficulty in doing chores (88% versus 60%) or going for a walk, run, or bike ride (84% versus 60%). A higher percentage of those with liver disease reported feeling anxious (92% versus 78%), isolated (100% versus 80%), and lonely (96% versus 72%) than those without liver disease. The mean number of hours missed from work and school in the past month was higher for those with liver disease (work: 10.9 h; school: 7.7 h) than those without liver disease (3.6 h for both). EPP-related HCU in the previous 12 months was higher for those with liver disease than those without liver disease, including more physician visits (mean of 16.5 versus 6.0) and emergency room visits (mean of 9.0 versus 1.9).

Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare genetic disorders. There are limited data regarding how these disorders are managed in real-world settings. The aim of this study was to document the characteristics and treatment patterns among patients diagnosed with EPP or XLP in general real-world settings in the United States. We, therefore, conducted a retrospective medical record review of patients diagnosed with EPP or XLP on or before July 1, 2020. Data were analyzed for patients with EPP (n = 299) and XLP (n = 91). Outcomes included demographic and clinical characteristics, diagnostic testing, therapy recommendations, office visits, emergency department visits, and hospitalizations. Costs were assigned to healthcare resources. Mean (standard deviation [SD]; median) time between the first symptom documented in the medical records and diagnosis was 2.9 (5.1; 1.3) years. The most common pre-diagnostic tests were liver function, total plasma and erythrocyte protoporphyrin, genetic tests, and renal function. Patients were advised to use sunscreen (85%) or modify their lifestyle (83%). Within 12 months of diagnosis, the mean (SD; median) number of office visits, emergency department visits, and inpatient hospitalizations related to EPP or XLP were 4.0 (3.5; 3.0), 0.8 (1.6; 0), and 0.4 (1.3; 0), respectively. Patients with EPP or XLP have several unmet needs, including timely and accurate diagnosis, symptom relief, and efficacious prevention of phototoxic reactions.

X-linked erythropoietic protoporphyria (XLEPP) is an ultra-rare inborn error of the heme biosynthesis characterised by the accumulation of large amounts of protoporphyrin IX (PPIX) and zinc-protoporphyrin in the erythrocytes. PPIX absorbs the energy of the visible light range and upon exposure causes painful phototoxic reactions and tissue damage. In addition, PPIX is excreted via the liver and bile, and can induce liver failure that requires life-saving liver transplantation. Case reports and data from a limited number of patients enrolled in a prospective study indicate that supplementation with iron, a co-substrate of the heme biosynthesis, can decrease blood PPIX concentrations and improve liver damage and photosensitivity in patients with XLEPP. However, long-term data on safety and effectiveness of iron supplementation in XLEPP to support this treatment strategy is limited.

Here, we report the experience and long-term effects over up to 8 years of iron supplementation of the four patients with XLEPP in the Swiss cohort.

Our study shows that iron supplementation was safe and effective in lowering blood PPIX concentrations in our patients in the long term.

However, monitoring for adequate dosing and long-term effects is advisable and a standardisation of treatment protocols and international best practice guidelines are needed.

X-linked sideroblastic anemia (XLSA) and X-linked protoporphyria (XLPP) are uncommon diseases caused by loss-of-function and gain-of-function mutations, respectively, in the erythroid form of 5-aminolevulinic acid synthetase (ALAS), ALAS2, which encodes the first enzyme in heme biosynthesis. A related congenital sideroblastic anemia (CSA) is due to mutations in SLC25A38 (solute carrier family 25 member A38), which supplies mitochondrial glycine for ALAS2 (SLC25A38-CSA). The lack of viable animal models has limited the studies on pathophysiology and development of therapies for these conditions. Here, using CRISPR-CAS9 gene editing technology, we have generated knockin mouse models that recapitulate the main features of XLSA and XLPP; and using conventional conditional gene targeting in embryonic stem cells, we also developed a faithful model of the SLC25A38-CSA. In addition to examining the phenotypes and natural history of each disease, we determine the effect of restriction or supplementation of dietary pyridoxine (vitamin B6), the essential cofactor of ALAS2, on the anemia and porphyria. In addition to the well-documented response of XLSA mutations to pyridoxine supplementation, we also demonstrate the relative insensitivity of the XLPP/EPP protoporphyrias, severe sensitivity of the XLSA models, and an extreme hypersensitivity of the SLC25A38-CSA model to pyridoxine deficiency, a phenotype that is not shared with another mouse hereditary anemia model, Hbbth3/+ β-thalassemia intermedia. Thus, in addition to generating animal models useful for examining the pathophysiology and treatment of these diseases, we have uncovered an unsuspected conditional synthetic lethality between the heme synthesis-related CSAs and pyridoxine deficiency. These findings have the potential to inform novel therapeutic paradigms for the treatment of these diseases.

Protoporphyria is a subtype of porphyria characterized primarily by painful phototoxic skin reactions after light exposure at specific wavelengths. Historically, phototherapy is not contraindicated in patients with protoporphyria since there have not been any reports of phototoxic reactions. However, patients with protoporphyria are advised to avoid direct sunlight. In this case report, we describe a neonate not known to have X-linked protoporphyria who received phototherapy for 1 to 2 hours. Within hours after initiation of phototherapy, this neonate developed a life-threatening reaction consisting of rash over the distribution of phototherapy, acute liver failure with coagulopathy, diffuse hypotonia with diaphragmatic failure, and subsequent acute respiratory failure that required mechanical ventilation. As in this case, patients with protoporphyria-related acute liver failure can have signs and symptoms similar to that of an acute hepatic porphyria attack. Neither neonatal reactions to phototherapy nor liver failure temporally associated with phototherapy have been reported in patients with X-linked protoporphyria. Early recognition of this entity is crucial in light of potential life-threatening complications. Therefore, providers must react quickly when neonates have abnormal reactions to phototherapy and consider protoporphyria in the differential diagnosis.

Xeroderma pigmentosum is a rare autosomal recessive genodermatoses characterized by a deficiency in nucleotide excision repair. Erythropoietic protoporphyria is a rare inherited metabolic disease caused by the perturbation of heme. Xeroderma pigmentosum-erythropoietic protoporphyria is exceedingly rare. Hereby, we firstly report a young Chinese patient of xeroderma pigmentosum Group A with erythropoietic protoporphyria carrying an XPA Met214AsnfsTer7 frameshift mutation and a homozygous splicing mutation, c.315-48T>C, in the proband's intron3 of FECH.

Porphyria denotes a heterogeneous group of metabolic disorders caused by anomalies in the biosynthesis of heme, a crucial component of hemoglobin and other vital hemoproteins [...].

Erythropoietic protoporphyria (EPP) is a genetic disorder stemming from reduced ferrochelatase expression, the final enzyme in the pathway of heme biosynthesis. A closely related condition, X-linked protoporphyria (XLP), bears similar clinical features although it arises from the heightened activity of δ-aminolevulinic acid synthase 2 (ALAS2), the first and normally rate-controlling enzyme in heme biosynthesis in developing red blood cells. Both of these abnormalities result in the buildup of protoporphyrin IX, leading to excruciating light sensitivity and, in a minority of cases, potentially fatal liver complications. Traditionally, managing EPP and XLP involved sun avoidance. However, the emergence of innovative therapies, such as dersimelagon, is reshaping the therapeutic landscape for these conditions. In this review, we summarize salient features of the properties of dersimelagon, shedding light on its potential role in advancing our understanding of treatment options for EPP and XLP.

Erythropoietic protoporphyria (EPP) is an inherited metabolic disease caused by the deficiency in ferrochelatase (FECH) encoded by the FECH gene, and it is inherited in an autosomal recessive manner. EPP usually produces acute pain photosensitivity after exposure to sunlight in infancy or early childhood, and liver failure is the most serious associated complication. This article reported an adult female case of EPP complicated with thyrotoxicosis and liver dysfunction which is a rare condition. The patient's liver function improved after liver protection treatment, her thyroid function returned to normal, and her EPP symptoms improved significantly. Moreover, the c.286C>T gene mutation may be the pathogenic locus of EPP. For patients with abnormal liver function, the possibility of EPP should be considered after the common causes are excluded, and FECH gene detection should be done to confirm the diagnosis in time. When EPP is associated with thyrotoxicosis and liver dysfunction, priority may be given to hepatoprotective therapy.

Congenital erythropoietic porphyria (CEP), also known as pink tooth or Gunther disease, is a rare hereditary disorder caused by an enzyme mutation in the heme biosynthesis pathway, which leads to the accumulation of immature and non-physiological protoporphyrin rings in various tissues. CEP is characterized by sun-exposed bullous skin lesions, hemolytic anemia, red/brown urine, and teeth staining.

We present a unique case of a 10-year-old Asian boy with CEP who presented with recurrent epistaxis, an unusual presentation for this condition. Based on clinical presentation and laboratory findings, including elevated urine uroporphyrin and coproporphyrin I and III levels, microcytic anemia, a higher red cell distribution width (RDW), and a lower platelet count, a thorough assessment and detailed workup resulted in a diagnosis of CEP. The patient underwent a successful splenectomy and recovered without any complications.

This case report aims to raise awareness among healthcare professionals about the uncommon and atypical presentation of CEP and its management options.

Protoporphyrin IX (PPIX) is an intermediate in the heme biosynthesis pathway. Abnormal accumulation of PPIX due to certain pathological conditions such as erythropoietic protoporphyria and X-linked protoporphyria causes painful phototoxic reactions of the skin, which can significantly impact daily life. Endothelial cells in the skin have been proposed as the primary target for PPIX-induced phototoxicity through light-triggered generation of reactive oxygen species. Current approaches for the management of PPIX-induced phototoxicity include opaque clothing, sunscreens, phototherapy, blood therapy, antioxidants, bone marrow transplantation, and drugs that increase skin pigmentation. In this review, we discuss the present understanding of PPIX-induced phototoxicity including PPIX production and disposition, conditions that lead to PPIX accumulation, symptoms and individual differences, mechanisms, and therapeutics.

Given its remarkable property to easily switch between different oxidative states, iron is essential in countless cellular functions which involve redox reactions. At the same time, uncontrolled interactions between iron and its surrounding milieu may be damaging to cells and tissues. Heme-the iron-chelated form of protoporphyrin IX-is a macrocyclic tetrapyrrole and a coordination complex for diatomic gases, accurately engineered by evolution to exploit the catalytic, oxygen-binding, and oxidoreductive properties of iron while minimizing its damaging effects on tissues. The majority of the body production of heme is ultimately incorporated into hemoglobin within mature erythrocytes; thus, regulation of heme biosynthesis by iron is central in erythropoiesis. Additionally, heme is a cofactor in several metabolic pathways, which can be modulated by iron-dependent signals as well. Impairment in some steps of the pathway of heme biosynthesis is the main pathogenetic mechanism of two groups of diseases collectively known as porphyrias and congenital sideroblastic anemias. In porphyrias, according to the specific enzyme involved, heme precursors accumulate up to the enzyme stop in disease-specific patterns and organs. Therefore, different porphyrias manifest themselves under strikingly different clinical pictures. In congenital sideroblastic anemias, instead, an altered utilization of mitochondrial iron by erythroid precursors leads to mitochondrial iron overload and an accumulation of ring sideroblasts in the bone marrow. In line with the complexity of the processes involved, the role of iron in these conditions is then multifarious. This review aims to summarise the most important lines of evidence concerning the interplay between iron and heme metabolism, as well as the clinical and experimental aspects of the role of iron in inherited conditions of altered heme biosynthesis.

Porphyrin and iron are ubiquitous and essential for sustaining life in virtually all living organisms. Unlike iron, which exists in many forms, porphyrin macrocycles are mostly functional as metal complexes. The iron-containing porphyrin, heme, serves as a prosthetic group in a wide array of metabolic pathways; including respiratory cytochromes, hemoglobin, cytochrome P450s, catalases, and other hemoproteins. Despite playing crucial roles in many biological processes, heme, iron, and porphyrin intermediates are potentially cytotoxic. Thus, the intersection of porphyrin and iron metabolism at heme synthesis, and intracellular trafficking of heme and its porphyrin precursors are tightly regulated processes. In this review, we discuss recent advances in understanding the physiological dynamics of eukaryotic ferrochelatase, a mitochondrially localized metalloenzyme. Ferrochelatase catalyzes the terminal step of heme biosynthesis, the insertion of ferrous iron into protoporphyrin IX to produce heme. In most eukaryotes, except plants, ferrochelatase is localized to the mitochondrial matrix, where substrates are delivered and heme is synthesized for trafficking to multiple cellular locales. Herein, we delve into the structural and functional features of ferrochelatase, as well as its metabolic regulation in the mitochondria. We discuss the regulation of ferrochelatase via post-translational modifications, transportation of substrates and product across the mitochondrial membrane, protein-protein interactions, inhibition by small-molecule inhibitors, and ferrochelatase in protozoal parasites. Overall, this review presents insight on mitochondrial heme homeostasis from the perspective of ferrochelatase.