Congenital erythropoietic porphyria.

Congenital erythropoietic porphyria (CEP) is a rare autosomal recessive disease due to the deficient, but not absent, activity of uroporphyrinogen III synthase (UROS), the fourth enzyme in the heme biosynthesis pathway. Biallelic variants in the UROS gene result in decreased UROS enzymatic activity and the accumulation of non-physiologic Type I porphyrins in cells and fluids. Overproduced uroporphyrins in haematopoietic cells are released into the circulation and distributed to tissues, inducing primarily hematologic and dermatologic symptoms. The clinical manifestations vary in severity ranging from non-immune hydrops fetalis in utero to mild dermatologic manifestations in adults. Here, the biochemical, molecular and clinical features of CEP as well as current and new treatment options, including the rescue of UROS enzyme activity by chaperones, are presented.

Exploring current and emerging therapies for porphyrias.

Porphyrias are rare, mostly inherited disorders resulting from altered activity of specific enzymes in the haem synthesis pathway that lead to accumulation of pathway intermediates. Photocutaneous symptoms occur when excess amounts of photoreactive porphyrins circulate in the blood to the skin, whereas increases in potentially neurotoxic porphyrin precursors are associated with neurovisceral symptoms. Current therapies are suboptimal and their mechanisms are not well established. As described here, emerging therapies address underlying disease mechanisms by introducing a gene, RNA or other specific molecule with the potential to cure or slow progression of the disease. Recent progress in nanotechnology and nanoscience, particularly regarding particle design and formulation, is expanding disease targets. More secure and efficient drug delivery systems have extended our toolbox for transferring specific molecules, especially into hepatocytes, and led to proof-of-concept studies in animal models. Repurposing existing drugs as molecular chaperones or haem synthesis inhibitors is also promising. This review summarizes key examples of these emerging therapeutic approaches and their application for hepatic and erythropoietic porphyrias.

Hematopoietic stem cell transplant for erythropoietic porphyrias in pediatric patients.

Cutaneous, hematopoietic, and hepatic manifestations of congenital erythropoietic porphyria (CEP) and erythropoietic protoporphyria (EPP) can be debilitating. We present our institution's experience with five patients with porphyria who underwent hematopoietic stem cell transplant (HSCT). Four patients with CEP, including three under age 2, received myeloablation. One patient with EPP, with prior liver transplant, received reduced intensity conditioning (RIC). Four patients are alive without porphyria symptomology and with full donor chimerism. HSCT corrects the defective heme pathway and should be considered early in patients with severe erythropoietic porphyrias to minimize end-organ damage. RIC regimens can minimize toxicity in patients with comorbidities.

Bone Marrow Transplantation in Congenital Erythropoietic Porphyria: Sustained Efficacy but Unexpected Liver Dysfunction.

Congenital erythropoietic porphyria (CEP) is a rare disease characterized by erosive photosensitivity and chronic hemolysis due to a defect of the enzyme uroporphyrinogen-III-synthase (UROS). To date, hematopoietic stem cell transplantation (HSCT) is the only curative therapy for the devastating early and severe form of the disease. We describe 6 patients with CEP treated with HSCT (3 of them twice after failure of a first graft) between 1994 and 2016 in our center, including 2 of the very first living patients treated more than 20 years ago. Four patients are doing well at 6 to 25 years post-HSCT, with near-normal biochemical parameters of porphyrin metabolism without the cutaneous or hematologic features of CEP. One patient died within the first year after HSCT from severe graft-versus-host disease (GVHD), and 1 child died of unexplained acute hepatic failure at 1 year after HSCT, despite full donor chimerism. Retrospectively, it appears that all but 1 child had increased transaminase activity with onset from the early postnatal period, which was significantly more marked in the child who died of liver failure. In contrast, liver function values progressively normalized after engraftment in all other children. Liver pathology before HSCT for 3 patients revealed varying degrees of portal, centrilobular, and perisinusoidal fibrosis; clarification of hepatocytes; and cytosolic porphyrin deposits. The liver porphyrin content in biopsy specimens was >60 times the normal values. Despite difficult engraftment, the long-term efficacy of HSCT in CEP appears to be favorable and reinforces its benefits for the severe form of CEP. Hepatic involvement requires careful evaluation before and after HSCT and further investigation into its pathophysiology and care.

Congenital erythropoietic porphyria: Recent advances.

Congenital erythropoietic porphyria (CEP) is a rare autosomal recessive disorder characterized by photosensitivity and by hematologic abnormalities in affected individuals. CEP is caused by mutations in the uroporphyrinogen synthase (UROS) gene. In three reported cases, CEP has been associated with a specific X-linked GATA1 mutation. Disease-causing mutations in either gene result in absent or markedly reduced UROS enzymatic activity. This in turn leads to the accumulation of the non-physiologic and photoreactive porphyrinogens, uroporphyrinogen I and coproporphyrinogen I, which damage erythrocytes and elicit a phototoxic reaction upon light exposure. The clinical spectrum of CEP depends on the level of residual UROS activity, which is determined by the underlying pathogenic loss-of-function UROS mutations. Disease severity ranges from non-immune hydrops fetalis in utero to late-onset disease with only mild cutaneous involvement. The clinical characteristics of CEP include exquisite photosensitivity to visible light resulting in bullous vesicular lesions which, when infected lead to progressive photomutilation of sun-exposed areas such as the face and hands. In addition, patients have erythrodontia (brownish discoloration of teeth) and can develop corneal scarring. Chronic transfusion-dependent hemolytic anemia is common and leads to bone marrow hyperplasia, which further increases porphyrin production. Management of CEP consists of strict avoidance of exposure to visible light with sun-protective clothing, sunglasses, and car and home window filters. Adequate care of ruptured vesicles and use of topical antibiotics is indicated to prevent superinfections and osteolysis. In patients with symptomatic hemolytic anemia, frequent erythrocyte cell transfusions may be necessary to suppress hematopoiesis and decrease marrow production of the phototoxic porphyrins. In severe transfection-dependent cases, bone marrow or hematopoietic stem cell transplantation has been performed, which is curative. Therapeutic approaches including gene therapy, proteasome inhibition, and pharmacologic chaperones are under investigation.

[The cutaneous porphyrias]. / Porphyries cutanées.

The porphyrias are a group of metabolic disorders resulting from an innate abnormality in haem biosynthesis, and the clinical settings of which vary according to the genetic enzyme abnormality in question. These are genetic disorders with autosomal dominant or recessive inheritance of varying penetrance, and whose clinical expression differs according to the preferential location of haem precursors. Different classifications have been proposed according to genetic inheritance, the enzyme anomaly at issue, and clinical expression. The clinical classification distinguishes between acute porphyria (acute intermittent porphyria, porphyria variegata, hereditary coproporphyria), bullous cutaneous porphyrias (porphyria cutanea tarda, porphyria variegata and hereditary coproporphyria), painful photosensitive acute cutaneous porphyrias (erythropoietic protoporphyria and X-linked dominant protoporphyria), and rare recessive porphyrias (congenital erythropoietic porphyria, Doss porphyria, hepatoerythropoietic porphyria and harderoporphyria). Treatment depends on the clinical expression of the disorder.

Acquired erythropoietic uroporphyria secondary to myelodysplastic syndrome with chromosome 3 alterations: a case report.

Congenital erythropoietic porphyria is a rare autosomal recessive disease caused by a deficiency of uroporphyrinogen III synthase, owing to mutations in UROS in chromosome 10. Occasionally, patients show a mild, late-onset disease, without germline UROS mutations, associated with haematological malignancies. We report a 65-year-old patient with photosensitivity, overexcretion of porphyrins and thrombocytopenia. Bone marrow analysis gave a diagnosis of myelodysplastic syndrome (MDS) with the presence of a derivative chromosome 3, possibly due to an inversion including 3q21 and 3q26 break points. After allogeneic stem-cell transplantation, complete remission of MDS and uroporphyria was achieved. To our knowledge, this is the first reported case of acquired erythropoietic uroporphyria associated with MDS, with chromosome 3 alterations.

Acute hepatic and erythropoietic porphyrias: from ALA synthases 1 and 2 to new molecular bases and treatments.

PURPOSE OF REVIEW: Many studies over the past decade have together identified new genes including modifier genes and new regulation and pathophysiological mechanisms in inherited inborn diseases of the heme biosynthetic pathway. A new porphyria has been characterized: X-linked protoporphyria and the perspective to have innovative treatment at very short-term became a reality. We will summarize how recent data on both ALAS1 and ALAS2 have informed our understanding of disease pathogenesis with an emphasis on how this information may contribute to new therapeutic strategies. RECENT FINDINGS: The development of clinical and biological porphyria networks improved the long-term follow up of cohorts. The ageing of patients have allowed for the identification of novel recurrently mutated genes, and highlighted long-term complications in acute hepatic porphyrias. The treatment of hepatic porphyrias by an RNAi-targeting hepatic ALAS1 is actually tested and may lead to improve the management of acute attacks.In erythropoietic porphyrias, the key role of ALAS2 as a gate keeper of the heme and subsequently hemoglobin synthesis has been demonstrated. Its implication as a modifier gene in over erythroid disorders has also been documented. SUMMARY: The knowledge of both the genetic abnormalities and the regulation of heme biosynthesis has increased over the last 5 years and open new avenues in the management of erythropoietic and acute hepatic porphyrias.

[Congenital erythropoietic porphyria : An update]. / Kongenitale erythropoetische Porphyrie : Ein Update.

BACKGROUND: Congenital erythropoetic porphria is a very rare type of autosomal recessive nonacute porphyria. Homozygous or compound heterozygous mutations in the uroporphyrinogen III consynthase gene cause a marked enzymatic deficiency of uroporphyrinogen III consynthase, the fourth enzyme along the heme biosynthetic pathway. CLINICAL PRESENTATION: Clinically, affected patients are characterized by a moderate to severe photosensitivity. Starting early in infancy, they develop blisters, erosions, and exulcerations in sun-exposed areas of the body, often resulting in scar formation and mutilation. Besides the cutaneous changes, hemolytic anemia, transfusion-dependent pancytopenia, hepatosplenomegaly and liver cirrhosis can occur. Due to increased susceptibility for infections and because of the hematological and hepatic complications, affected individuals have a decreased life expectancy, rarely exceeding 40 years of age. TREATMENT: Currently, no causal treatment is available for the disorder. Therefore, the most important therapeutic modality is strict avoidance of sunlight, preferably by inversion of the day-night rhythm, or at least consequent photoprotection with adequate clothing. In severe cases, bone marrow or stem cell transplantation should be considered.

[Erythropoietic protoporphyria : Clinical manifestations, diagnosis and new therapeutic possibilities]. / Erythropoetische Protoporphyrie : Klinik, Diagnostik und neue therapeutische Möglichkeiten.

BACKGROUND: Erythropoietic protoporphyria, the second most common type of the cutaneous porphyrias, is due to an enzymatic deficiency of ferrochelatase, the last enzyme in heme biosynthesis. The enzyme defect leads to an accumulation of protoporphyrin IX in erythrocytes and an elevated excretion of this metabolite in the feces. CLINICAL PRESENTATION: Usually, disease onset is in early infancy, characterized by increased photosensitivity. During or shortly after sunlight exposure, affected individuals suffer from burning, stinging, itching, and pain in sun-exposed skin areas. These symptoms lead to a considerably reduced quality of life and strict avoidance of sunlight exposure. Subacute symptoms include visible changes like edema and erythema. In the further course of the disease, chronic signs such as lichenification and scarring may occur. A severe complication of hepatic protoporphyrin IX accumulation is the development of a potentially life-threatening fulminant liver failure. Therefore, hepatic laboratory tests and ultrasound of the liver should be performed regularly. THERAPY: Traditionally, therapy merely consisted of consequent photoprotection and orally administered ß-carotene. A novel treatment option is afamelanotide (Scenesse®), a synthetic analogue of the naturally occurring α-melanocyte stimulating hormone. Afamelanotide, administered as a subcutaneous implant, induces eumelanin production, independent of preceding UV light exposure. This may enable patients with erythropoietic protoporphyria to stay in sunlight significantly longer than previously possible without complaints, thus, substantially improving quality of life.

Metabolic correction of congenital erythropoietic porphyria with iPSCs free of reprogramming factors.

Congenital erythropoietic porphyria (CEP) is due to a deficiency in the enzymatic activity of uroporphyrinogen III synthase (UROS); such a deficiency leads to porphyrin accumulation and results in skin lesions and hemolytic anemia. CEP is a candidate for retrolentivirus-mediated gene therapy, but recent reports of insertional leukemogenesis underscore the need for safer methods. The discovery of induced pluripotent stem cells (iPSCs) has opened up new horizons in gene therapy because it might overcome the difficulty of obtaining sufficient amounts of autologous hematopoietic stem cells for transplantation and the risk of genotoxicity. In this study, we isolated keratinocytes from a CEP-affected individual and generated iPSCs with two excisable lentiviral vectors. Gene correction of CEP-derived iPSCs was obtained by lentiviral transduction of a therapeutic vector containing UROS cDNA under the control of an erythroid-specific promoter shielded by insulators. One iPSC clone, free of reprogramming genes, was obtained with a single proviral integration of the therapeutic vector in a genomic safe region. Metabolic correction of erythroblasts derived from iPSC clones was demonstrated by the disappearance of fluorocytes. This study reports the feasibility of porphyria gene therapy with the use of iPSCs.

Report of a novel Indian case of congenital erythropoietic porphyria and overview of therapeutic options.

Congenital erythropoietic porphyria is a rare disorder of heme biosynthesis, resulting from decreased enzymatic activity of uroporphyrinogen III synthase. Clinical manifestations are heterogenous, of variable severity, and with occasional phenotypic-genotypic correlation. A 14-month-old boy developed fever, extensive dermatitis, and reddish colored urine. Anemia, erythrodontia, hepatosplenomegaly, and massive urinary elimination of predominantly type I porphyrins was suggestive of congenital erythropoietic porphyria. Although hemolysis remained mild and compensated, facial and digital mutilation developed indicative of moderate clinical phenotype. Mutational analysis revealed compound heterozygosity of mutant alleles, including a novel mutation (p.Pro190Leu). The child received supportive management and underwent facial reconstruction successfully.

Successful treatment of congenital erythropoietic porphyria using matched unrelated hematopoietic stem cell transplantation.

Congenital erythropoietic porphyria (CEP), or Günther's disease, is an inborn error of metabolism produced by a deficiency of uroporphyrinogen III synthase (UROS), the fourth enzyme of the heme biosynthesis pathway. This enzymatic defect induces the accumulation of isomer I porphyrins in erythrocytes, skin, and tissues, producing various clinical manifestations. Severe cases are characterized by extreme photosensitivity, causing scarring and mutilations, and by hemolytic anemia, reducing life expectancy. CEP is caused by mutations in the UROS gene, and one of the most severe forms of the disease is associated with a cysteine to arginine substitution at residue 73 of the protein (C73R). CEP has been successfully treated only by the transplantation of hematopoietic precursors. We report the case of a male infant with severe postdelivery symptoms diagnosed with CEP and found to be homozygous for the C73R mutation. He underwent successful allogeneic bone marrow transplantation from a matched unrelated donor at 7 months of age. The hemolytic anemia was corrected and the porphyrin overproduction was significantly reduced. The patient remained asymptomatic after 1 year. This new case confirms that patients with severe CEP can benefit from early postnatal hematopoietic stem cell transplantation.

Very Early Diagnosis and Management of Congenital Erythropoietic Porphyria.

Congenital erythropoietic porphyria (CEP), a rare form of porphyria, is caused by a defect in the heme biosynthesis pathway of the enzyme uroporphyrinogen III synthase (UROS). Uroporphyrinogen III synthase deficiency leads to an accumulation of nonphysiological porphyrins in bone marrow, red blood cells, skin, bones, teeth, and spleen. Consequently, the exposure to sunlight causes severe photosensitivity, long-term intravascular hemolysis, and eventually, irreversible mutilating deformities. Several supportive therapies such as strict sun avoidance, physical sunblocks, red blood cells transfusions, hydroxyurea, and splenectomy are commonly used in the management of CEP. Currently, the only available curative treatment of CEP is hematopoietic stem cell transplantation (HSCT). In this article, we present a young girl in which precocious genetic testing enabled early diagnosis and allowed curative treatment with HSCT for CEP at the age of 3 months of age, that is, the youngest reported case thus far.

Bullous lesions following phototherapy in a newborn.

A male infant presented with progressive jaundice immediately after birth. Fecal acholia and choluria associated with extensive bullous skin lesions in his trunk, abdomen, and upper and lower limbs developed during phototherapy. Several diagnostic hypotheses were presented, including neonatal porphyria, hemochromatosis, Alagille syndrome, and neonatal lupus. A 24-hour urine sample for the dosage of urinary porphyrins was collected, showing high results (1823.6µg in 100mL). At 50 days of life, fluorescence spectroscopy using a Wood's lamp revealed simultaneous bright red fluorescence of urine-stained diapers and sample blood. A definitive diagnosis of congenital erythropoietic porphyria was made following identification of a mutation of the uroporphyrinogen synthetases III gene on genetic testing. The patient was subsequently maintained in a low light environment since then, resulting in improvement of the lesions. Congenital erythropoietic porphyria is a disease of the group of porphyrias that presents shortly after birth with blistering occurring in regions exposed to the sun or other ultraviolet light. Atrophic scars, mutilated fingers, and bright red fluorescence of the urine and teeth may also be observed. There is no specific treatment, and prophylaxis comprising a total avoidance of sunlight is generally recommended. A high degree of suspicion is required for diagnosis. An early diagnosis can lead to less damage. Here, we present the case of a newborn with congenital erythropoietic porphyria diagnosed after presenting with bullous lesions secondary to phototherapy.

A management algorithm for congenital erythropoietic porphyria derived from a study of 29 cases.

BACKGROUND: Congenital erythropoietic porphyria (CEP) is an autosomal recessive photomutilating porphyria with onset usually in childhood, where haematological complications determine prognosis. Due to its extreme rarity and clinical heterogeneity, management decisions in CEP are often difficult. OBJECTIVES: To develop a management algorithm for patients with CEP based on data from carefully characterized historical cases. METHODS: A single investigator collated data related to treatments and their outcomes in 29 patients with CEP from the U.K., France, Germany and Switzerland. RESULTS: Six children were treated with bone marrow transplantation (BMT); five have remained symptomatically cured up to 11.5 years post-transplantation. Treatments such as oral charcoal, splenectomy and chronic hypertransfusion were either of no benefit or were associated with complications and negative impact on health-related quality of life. Lack of consistent genotype-phenotype correlation meant that this could not be used to predict disease prognosis. The main poor prognostic factors were early age of disease onset and severity of haematological manifestations. CONCLUSIONS: A management algorithm is proposed where every patient, irrespective of disease severity at presentation, should receive a comprehensive, multidisciplinary clinical assessment and should then be reviewed at intervals based on their predicted prognosis, and the rate of onset of complications. A BMT should be considered in those with progressive, symptomatic haemolytic anaemia and/or thrombocytopenia. Uroporphyrinogen III synthase genotypes associated with poor prognosis would additionally justify consideration for a BMT. Rigorous photoprotection of the skin and eyes from visible light is essential in all patients.