Purple pigments: the pathophysiology of acute porphyric neuropathy

[Acute hepatic porphyrias: pathophysiology and pathogenesis of acute attacks]

Heme is an iron-containing molecule essential for virtually all living organisms. However, excessive heme is cytotoxic, necessitating tight regulation of intracellular heme concentration. The acute hepatic porphyrias (AHPs) are a group of rare inborn errors of heme biosynthesis that are characterized by episodic acute neurovisceral attacks that are precipitated by various factors. The AHPs are often misdiagnosed, as the acute attack symptom are non-specific and can be attributed to other more common causes. Understanding how heme biosynthesis is dysregulated in AHP patients and the mechanism by which acute attacks are precipitated will aid in accurate and rapid diagnoses, and subsequently, appropriate treatment of these disorders. Therefore, this review article will focus on the biochemical and molecular changes that occur during an acute attack and present what is currently known regarding the underlying pathogenesis of acute attacks.

Neurogenetic motor disorders

Advances in the field of neurogenetics have practical applications in rapid diagnosis on blood and body fluids to extract DNA, obviating the need for invasive investigations. The ability to obtain a presymptomatic diagnosis through genetic screening and biomarkers can be a guide to life-saving disease-modifying therapy or enzyme replacement therapy to compensate for the deficient disease-causing enzyme. The benefits of a comprehensive neurogenetic evaluation extend to family members in whom identification of the causal gene defect ensures carrier detection and at-risk counseling for future generations. This chapter explores the many facets of the neurogenetic evaluation in adult and pediatric motor disorders as a primer for later chapters in this volume and a roadmap for the future applications of genetics in neurology.

Derivative Matrix-Isopotential Synchronous Spectrofluorimetry and Hantzsch Reaction: A Direct Route to Simultaneous Determination of Urinary δ-Aminolevulinic Acid and Porphobilinogen

Early and sensitive detection of δ-aminolevulinic acid (δ-ALA) and porphobilinogen (PBG) is the cornerstone of diagnosis and effective treatment for acute porphyria. However, at present, the quantifying strategies demand multiple solvent extraction steps or chromatographic approaches to separate δ-ALA and PBG prior to quantification. These methods are both time-consuming and laborious. Otherwise, in conventional spectrofluorimetry, the overlapping spectra of the two analytes cause false diagnosis. To overcome this challenge, we present a two-step approach based on derivative matrix-isopotential synchronous fluorescence spectrometry (DMISFS) and the Hantzsch reaction, realizing the simple and simultaneous detection of δ-ALA and PBG in urine samples. The first step is chemical derivatization of the analytes by Hantzsch reaction. The second step is the determination of the target analytes by combining MISFS and the first derivative technique. The proposed approach accomplishes following advantages: 1) The MISFS technique improves the spectral resolution and resolves severe spectral overlap of the analytes, alleviating tedious and complicated pre-separation processes; 2) First derivative technique removes the background interference of δ-ALA on PBG and vice versa, ensuring high sensitivity; 3) Both the analytes can be determined simultaneously via single scanning, enabling rapid detection. The obtained detection limits for δ-ALA and PBG were 0.04 μmol L−1 and 0.3 μmol L−1, respectively. Within-run precisions (intra and inter-day CVs) for both the analytes were <5%. Further, this study would serve to enhance the availability of early and reliable quantitative diagnosis for acute porphyria in both scientific and clinical laboratories.

Acute porphyrias - A neurological perspective

Acute hepatic porphyrias (AHP) can cause severe neurological symptoms involving the central, autonomic, and peripheral nervous system. Due to their relative rarity and their chameleon-like presentation, delayed diagnosis and misdiagnosis are common. AHPs are genetically inherited disorders that result from heme biosynthesis enzyme deficiencies and comprise four forms: acute intermittent porphyria (AIP), variegate porphyria (VP), hereditary coproporphyria (HCP), and ALA-dehydratase porphyria (ALADP). Depending on the clinical presentation, the main differential diagnoses are Guillain-Barré syndrome and autoimmune encephalitis. Red flags that could raise the suspicion of acute porphyria are neurological symptoms starting after severe (abdominal) pain, in association with reddish urine, hyponatremia or photodermatitis, and the presence of encephalopathy and/or axonal neuropathy. We highlight the diagnostic difficulties by presenting three cases from our neurological intensive care unit and give a comprehensive overview about the diagnostic findings in imaging, electrophysiology, and neuropathology.

Acute Hepatic Porphyria: Pathophysiological Basis of Neuromuscular Manifestations

Acute hepatic porphyria represents a rare, underdiagnosed group of inherited metabolic disorders due to hereditary defects of heme group biosynthesis pathway. Most patients have their definite diagnosis after several years of complex and disabling clinical manifestations and commonly after life-threatening acute neurovisceral episodes or severe motor handicap. Many key studies in the last two decades have been performed and led to the discovery of novel possible diagnostic and prognostic biomarkers and to the development of new therapeutic purposes, including small interfering RNA-based therapy, specifically driven to inhibit selectively delta-aminolevulinic acid synthase production and decrease the recurrence number of severe acute presentation for most patients. Several distinct mechanisms have been identified to contribute to the several neuromuscular signs and symptoms. This review article aims to present the current knowledge regarding the main pathophysiological mechanisms involved with the acute and chronic presentation of acute hepatic porphyria and to highlight the relevance of such content for clinical practice and in decision making about therapeutic options.

Severe neuropathic attack in a woman with acute intermittent porphyria: a case report

Acute intermittent porphyria (AIP) is a rare autosomal dominant metabolic disease with a broad spectrum of clinical manifestations, and can be easily confused with other diseases. Many patients with porphyria may have symptoms of peripheral nerve damage during an AIP attack, but most such patients are usually only mildly affected. Herein, we describe the case of an undiagnosed woman who developed overall weakness and respiratory failure within 48 hours, leading to her referral to the intensive care unit. Her neuropathy rapidly deteriorated, leading to quadriplegia and bulbar palsy within 14 days. Finally, the reddish color of her urine and further genetic analysis led to a diagnosis of AIP. The patient was treated with intravenous glucose infusion and her condition gradually improved; however, severe neurological sequelae remained. To the best of our knowledge, the AIP reported in this case, involving rapid and severe neuropathy, is extremely rare worldwide. A diagnosis of AIP should therefore be considered when patients present with severe progressive neuropathy. Moreover, early diagnosis may considerably improve patient prognosis.

Porphyric neuropathy

Acute hepatic porphyrias are inherited metabolic disorders that may present with polyneuropathy, which if not diagnosed early can lead to quadriparesis, respiratory weakness, and death. Porphyric neuropathy is an acute to subacute motor predominant axonal neuropathy with a predilection for the upper extremities and usually preceded by a predominantly parasympathetic autonomic neuropathy. The rapid progression and associated dysautonomia mimic Guillain-Barré syndrome but are distinguished by the absence of cerebrospinal fluid albuminocytologic dissociation, progression beyond 4 wk, and associated abdominal pain. Spot urine test to assess the porphyrin precursors delta-aminolevulinic acid and porphobilinogen can provide a timely diagnosis during an acute attack. Timely treatment with intravenous heme, carbohydrate loading, and avoidance of porphyrinogenic medications can prevent further neurological morbidity and mortality.

HEME: a neglected player in nociception?

Despite increasing progress in the understanding of the pathophysiology of pain, current management of pain syndromes is still unsatisfactory. The recent discovery of novel pathways associated with pain insensitivity in humans represents a unique opportunity to improve our knowledge on the pathophysiology of pain. Heme metabolism recently emerged as a crucial regulator of nociception. Of note, alteration of heme metabolism has been associated with pain insensitivity as well as with acute and chronic pain in porphyric neuropathy and hemolytic diseases. However, the molecular mechanisms linking heme to the pain pathways still remain unclear. The review focuses on the major heme-regulated processes relevant for sensory neurons' maintenance, peripheral and central sensitization as well as for pain comorbidities, like anxiety and depression. By discussing the body of knowledge on the topic, we provide a novel perspective on the molecular mechanisms linking heme to nociception.

Acute Intermittent Porphyria: An Overview of Therapy Developments and Future Perspectives Focusing on Stabilisation of HMBS and Proteostasis Regulators

Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease with low clinical penetrance, caused by mutations in the hydroxymethylbilane synthase (HMBS) gene, which encodes the third enzyme in the haem biosynthesis pathway. In susceptible HMBS mutation carriers, triggering factors such as hormonal changes and commonly used drugs induce an overproduction and accumulation of toxic haem precursors in the liver. Clinically, this presents as acute attacks characterised by severe abdominal pain and a wide array of neurological and psychiatric symptoms, and, in the long-term setting, the development of primary liver cancer, hypertension and kidney failure. Treatment options are few, and therapies preventing the development of symptomatic disease and long-term complications are non-existent. Here, we provide an overview of the disorder and treatments already in use in clinical practice, in addition to other therapies under development or in the pipeline. We also introduce the pathomechanistic effects of HMBS mutations, and present and discuss emerging therapeutic options based on HMBS stabilisation and the regulation of proteostasis. These are novel mechanistic therapeutic approaches with the potential of prophylactic correction of the disease by totally or partially recovering the enzyme functionality. The present scenario appears promising for upcoming patient-tailored interventions in AIP.

Acute hepatic porphyrias for the neurologist: current concepts and perspectives

BACKGROUND

Acute hepatic porphyrias represent an expanding group of complex inherited metabolic disorders due to inborn errors of metabolism involving heme biosynthesis.

OBJECTIVE

We aimed to review the main clinical and therapeutic aspects associated with acute hepatic porphyrias.

METHODS

The authors provided a wide non-systematic review of current concepts and recently acquired knowledge about acute hepatic porphyrias.

RESULTS

Acute neurovisceral attacks are the most common and life-threatening presentation of this group and are often considered the main clinical manifestation by clinicians during differential diagnosis and the start of proper diagnostic work-up for acute porphyrias. However, atypical presentations with central nervous system involvement, neuropsychiatric disturbances, and some subtypes with photosensitivity usually make the definite diagnosis difficult and late. Early therapeutic interventions are essential during emergency treatment and intercritical periods to avoid recurrent severe presentations. The availability of new disease-modifying therapeutic proposals based on small interfering RNA (siRNA)-based therapies, complementary to the classic intravenous glucose infusion and hemin-based treatments, emphasizes the importance of early diagnosis and genetic counseling of patients.

CONCLUSIONS

This review article highlights the main biochemical, pathophysiological, clinical, and therapeutic aspects of acute hepatic porphyrias in clinical practice.

Acute intermittent porphyria: focus on possible mechanisms of acute and chronic manifestations

Porphyrias are a group of inherited metabolic diseases that include eight types, each of which is caused by a mutation that affects an enzyme of the heme biosynthetic pathway. When an enzyme defect has physiological significance, it leads to overproduction of pathway precursors prior to the defective step. The partial absence of the third enzyme in the heme biosynthetic pathway, porphobilinogen deaminase (PBGD) also known as hydroxymethylbilane synthase (HMBS), results in acute intermittent porphyria (AIP), which affects mainly women. Subjects who had AIP symptoms were deemed to have manifest AIP (MAIP). Clinical manifestations are usually diverse and non-specific. Acute AIP episodes may present with abdominal pain, nausea, and vomiting, and repeated episodes may result in a series of chronic injuries. Therefore, studying the mechanisms of acute and chronic manifestations of AIP is of great significance. This review aims to summarize the possible mechanisms of acute and chronic manifestations in patients with AIP.

The Multifaceted Role of Heme in Cancer

Heme, an iron-containing porphyrin, is of vital importance for cells due to its involvement in several biological processes, including oxygen transport, energy production and drug metabolism. Besides these vital functions, heme also bears toxic properties and, therefore, the amount of heme inside the cells must be tightly regulated. Similarly, heme intake from dietary sources is strictly controlled to meet body requirements. The multifaceted nature of heme renders it a best candidate molecule exploited/controlled by tumor cells in order to modulate their energetic metabolism, to interact with the microenvironment and to sustain proliferation and survival. The present review summarizes the literature on heme and cancer, emphasizing the importance to consider heme as a prominent player in different aspects of tumor onset and progression.

Porphyrias: A clinically based approach

BACKGROUND

Porphyrias are a group of metabolic diseases, individually rare but with an important combined prevalence. Because of their pathological complexity and clinical heterogeneity, they present a challenging diagnosis. The present review aims to provide a clinically based approach to the recognition and treatment of these disorders.

METHODS

We carried out a search in PubMed, with the keyword "porphyria", for reviews published in English from 2010 until 2017.

RESULTS

The research yielded 196 papers, of which 64 were included in the final narrative review.

CONCLUSIONS

Porphyrias can be divided based on clinical presentation in acute neurovisceral, chronic cutaneous bullous, chronic cutaneous non-bullous and acute neurovisceral/chronic cutaneous bullous. Each individual porphyria presents a characteristic pattern of porphyrins in plasma, urine, stool and red blood cells. As such, diagnosis is easily obtained by following a simple diagnostic algorithm. Early recognition is key in managing these diseases. Neurovisceral porphyrias require acute support therapy and chronic eviction of precipitating factors. Cutaneous prophyrias, as photosensitivity disorders, rely on sunlight avoidance and, in some cases, specific therapeutic interventions. Given the rarity of these conditions, physician awareness is crucial.

Measurement of axonal excitability: Consensus guidelines

Measurement of axonal excitability provides an in vivo indication of the properties of the nerve membrane and of the ion channels expressed on these axons. Axonal excitability techniques have been utilised to investigate the pathophysiological mechanisms underlying neurological diseases. This document presents guidelines derived for such studies, based on a consensus of international experts, and highlights the potential difficulties when interpreting abnormalities in diseased axons. The present manuscript provides a state-of-the-art review of the findings of axonal excitability studies and their interpretation, in addition to suggesting guidelines for the optimal performance of excitability studies.

Acute Intermittent Porphyria: A Report of 3 Cases with Neuropathy

The porphyrias are metabolic disorders due to a defect in the heme biosynthetic pathway. Patients have diverse clinical presentations with neuropathy being frequent in acute intermittent porphyria (AIP). Associated symptoms are abdominal pain and seizures. Three patients presenting with neuropathy were later diagnosed with AIP on the basis of clinical features, erythrocyte porphobilinogen deaminase activity, neuropathic patterns, and nerve conduction studies. Testing for the HMBS genetic mutation confirmed the diagnosis of AIP in 1 patient. The findings from this case series confirm that porphyric neuropathy in AIP is a predominantly motor neuropathy with differing neuropathic presentations ranging from focal motor neuropathy to quadriplegia and respiratory failure.

Unraveling the Role of Heme in Neurodegeneration

Heme (iron-protoporphyrin IX) is an essential co-factor involved in several biological processes, including neuronal survival and differentiation. Nevertheless, an excess of free-heme promotes oxidative stress and lipid peroxidation, thus leading to cell death. The toxic properties of heme in the brain have been extensively studied during intracerebral or subarachnoid hemorrhages. Recently, a growing number of neurodegenerative disorders have been associated to alterations of heme metabolism. Hence, the etiology of such diseases remains undefined. The aim of this review is to highlight the neuropathological role of heme and to discuss the major heme-regulated pathways that might be crucial for the survival of neuronal cells. The understanding of the molecular mechanisms linking heme to neurodegeneration will be important for therapeutic purposes.

Recurrent abdominal pain as principal clinical manifestation of acute intermittent porphyria: A case report and literature review

Acute intermittent porphyria (AIP), an autosomal dominant disorder, is caused by a partial deficiency of porphobilinogen deaminase (PBGD), which is also named hydroxymethylbilane synthase (HMBS), the third enzyme in the heme biosynthetic pathway. In October 2015, a women presented with recurrent abdominal pain for 2 years. Using direct sequencing, we identified a hererozygous nonsense mutation, C to T, in exon 3 of HMBS at position 3782, resulting in a change of glutamine codon to termination codon (Q34*) in this patient. This mutation can lead to a decrease in the activity of heme biosynthetic enzyme PBGD, which is related to AIP.

Update review of the acute porphyrias

Acute porphyrias are rare inherited disorders due to deficiencies of haem synthesis enzymes. To date, all UK cases have been one of the three autosomal dominant forms, although penetrance is low and most gene carriers remain asymptomatic. Clinical presentation is typically with acute neurovisceral attacks characterised by severe abdominal pain, vomiting, tachycardia and hypertension. Severe attacks may be complicated by hyponatraemia, peripheral neuropathy sometimes causing paralysis, seizures and psychiatric features. Attacks are triggered by prescribed drugs, alcohol, hormonal changes, fasting or stress. The diagnosis is made by finding increased porphobilinogen excretion in a light-protected random urine sample. Management includes administration of intravenous human haemin and supportive treatment with non-porphyrinogenic drugs. A few patients develop recurrent attacks, a chronic illness requiring specialist management. Late complications include chronic pain, hepatocellular carcinoma, chronic renal failure and hypertension. In the UK, the National Acute Porphyria Service provides clinical advice and supplies haemin when indicated.

A Comprehensive Rehabilitation Program and Follow-up Assessment for Acute Intermittent Porphyria

Acute intermittent porphyria (AIP) is an infrequent metabolic disease that can cause severe disability or death without timely treatment. A porphyric attack occurs when genetic factors combine with trigger factors, and diagnosis may be delayed owing to nonspecific symptoms. Recovery from AIP can be nearly or fully complete with proper treatment, which includes intravenous hematin administration, the control of trigger factors, and a comprehensive rehabilitation program. The aim of this case report was to describe the clinical evolution of a 43-year-old woman with AIP and a polyneuropathy. The patient was treated through a comprehensive rehabilitation program, with outcomes evaluated by the Functional Independence Measure and the Berg scales during rehabilitation and postdischarge follow-up. After completing the comprehensive rehabilitation program, the patient achieved a satisfactory level of functional independence, allowing for social and work reintegration. We conclude that an early and multidisciplinary approach is essential for regaining optimal functionality after AIP.

Mitochondrial energetic defects in muscle and brain of a Hmbs-/- mouse model of acute intermittent porphyria

Acute intermittent porphyria (AIP), an autosomal dominant metabolic disease (MIM #176000), is due to a deficiency of hydroxymethylbilane synthase (HMBS), which catalyzes the third step of the heme biosynthetic pathway. The clinical expression of the disease is mainly neurological, involving the autonomous, central and peripheral nervous systems. We explored mitochondrial oxidative phosphorylation (OXPHOS) in the brain and skeletal muscle of the Hmbs(-/-) mouse model first in the basal state (BS), and then after induction of the disease with phenobarbital and treatment with heme arginate (HA). The modification of the respiratory parameters, determined in mice in the BS, reflected a spontaneous metabolic energetic adaptation to HMBS deficiency. Phenobarbital induced a sharp alteration of the oxidative metabolism with a significant decrease of ATP production in skeletal muscle that was restored by treatment with HA. This OXPHOS defect was due to deficiencies in complexes I and II in the skeletal muscle whereas all four respiratory chain complexes were affected in the brain. To date, the pathogenesis of AIP has been mainly attributed to the neurotoxicity of aminolevulinic acid and heme deficiency. Our results show that mitochondrial energetic failure also plays an important role in the expression of the disease.

Clinical presentation and electrophysiological findings of porphyric neuropathies: a follow-up study

INTRODUCTION

A case series of acute intermittent porphyria (AIP) is described that focuses on the clinical course of the disease with regard to neurological manifestations of the peripheral nervous system.

METHODS

Eight patients were diagnosed with AIP on the basis of characteristic clinical findings, erythrocyte porphobilinogendeaminase activity, neuropathic patterns, serial changes in nerve conduction studies (NCS), and temporal relationship of central nervous system involvement.

RESULTS

Six patients diagnosed with AIP<2 months after symptom onset had neuropathy that was predominantly upper extremity, motor, and proximal. NCS recovery rates were slower in the lower than the upper limbs. Two patients diagnosed >2 months after symptom onset had distal sensorimotor polyneuropathy.

CONCLUSIONS

The findings from this case series suggest that the peripheral nerves may be differentially and selectively involved in different diagnostic stages of porphyric neuropathy.

Best practice guidelines on clinical management of acute attacks of porphyria and their complications

The British and Irish Porphyria Network guidelines describe best practice in the clinical assessment, investigation and management of acute porphyria attacks and their complications, including severe attacks with neuropathy. Acute attacks of porphyria may occur in acute intermittent porphyria (AIP), variegate porphyria (VP) and hereditary coproporphyria (HCP). Aminolaevulinic acid dehydratase deficiency porphyria (ADP) is a very rare autosomal recessive porphyria; only six cases substantiated by mutation analysis have yet been described in the literature. Urinary porphobilinogen (PBG) is always raised in an acute attack due to AIP, VP or HCP and this analysis is essential to confirm the diagnosis. A positive result in a qualitative or semi-quantitative screening test must be followed by PBG quantitation at the earliest opportunity. However in a severely ill patient, treatment should not be delayed. Removal of precipitating factors, effective analgesia and control of symptoms with safe medication, attention to nutrition and fluid balance are essential. The indications for use of intravenous haem arginate are set out, together with advice on its administration. A small proportion of acute porphyria patients develop recurrent attacks and management options that may be considered include gonadotrophin-releasing hormone analogues, 'prophylactic' regular haem arginate infusion or ultimately, liver transplantation.

Conformational stability and activity analysis of two hydroxymethylbilane synthase mutants, K132N and V215E, with different phenotypic association with acute intermittent porphyria

The autosomal dominantly inherited disease AIP (acute intermittent porphyria) is caused by mutations in HMBS [hydroxymethylbilane synthase; also known as PBG (porphobilinogen) deaminase], the third enzyme in the haem biosynthesis pathway. Enzyme-intermediates with increasing number of PBG molecules are formed during the catalysis of HMBS. In this work, we studied the two uncharacterized mutants K132N and V215E comparative with wt (wild-type) HMBS and to the previously reported AIP-associated mutants R116W, R167W and R173W. These mainly present defects in conformational stability (R116W), enzyme kinetics (R167W) or both (R173W). A combination of native PAGE, CD, DSF (differential scanning fluorimetry) and ion-exchange chromatography was used to study conformational stability and activity of the recombinant enzymes. We also investigated the distribution of intermediates corresponding to specific elongation stages. It is well known that the thermostability of HMBS increases when the DPM (dipyrromethane) cofactor binds to the apoenzyme and the holoenzyme is formed. Interestingly, a decrease in thermal stability was measured concomitant to elongation of the pyrrole chain, indicating a loosening of the structure prior to product release. No conformational or kinetic defect was observed for the K132N mutant, whereas V215E presented lower conformational stability and probably a perturbed elongation process. This is in accordance with the high association of V215E with AIP. Our results contribute to interpret the molecular mechanisms for dysfunction of HMBS mutants and to establish genotype–phenotype relations for AIP.

PORPHOBILINOGEN DEAMINASE deficiency alters vegetative and reproductive development and causes lesions in Arabidopsis

The Arabidopsis rugosa1 (rug1) mutant has irregularly shaped leaves and reduced growth. In the absence of pathogens, leaves of rug1 plants have spontaneous lesions reminiscent of those seen in lesion-mimic mutants; rug1 plants also express cytological and molecular markers associated with defence against pathogens. These rug1 phenotypes are made stronger by dark/light transitions. The rug1 mutant also has delayed flowering time, upregulation of the floral repressor FLOWERING LOCUS C (FLC) and downregulation of the flowering promoters FT and SOC1/AGL20. Vernalization suppresses the late flowering phenotype of rug1 by repressing FLC. Microarray analysis revealed that 280 nuclear genes are differentially expressed between rug1 and wild type; almost a quarter of these genes are involved in plant defence. In rug1, the auxin response is also affected and several auxin-responsive genes are downregulated. We identified the RUG1 gene by map-based cloning and found that it encodes porphobilinogen deaminase (PBGD), also known as hydroxymethylbilane synthase, an enzyme of the tetrapyrrole biosynthesis pathway, which produces chlorophyll, heme, siroheme and phytochromobilin in plants. PBGD activity is reduced in rug1 plants, which accumulate porphobilinogen. Our results indicate that Arabidopsis PBGD deficiency impairs the porphyrin pathway and triggers constitutive activation of plant defence mechanisms leading to leaf lesions and affecting vegetative and reproductive development.

Plasma and red cell exchange transfusions for erythropoietic protoporphyria: a case report and review of the literature

Erythropoietic protoporphyria (EPP) is a rare and usually autosomal dominant disorder characterized by ferrochelatase deficiency and accumulation of protoporphyrin in red blood cells (RBCs), skin, and liver. A small minority of patients develop severe liver dysfunction for which optimum treatment is lacking. Therapeutic plasma exchange (TPE) and RBC exchange (RCE) have been anecdotally reported to benefit patients with EPP and liver failure. A 50-year-old female with EPP developed severe liver dysfunction after knee replacement surgery and high-dose acetaminophen use. Liver biopsy showed cholestatic liver injury without fibrosis. A total of 20 TPE procedures, six RCE procedures, and then 14 more TPE procedures were performed as adjunctive therapy with the purpose of preventing progression to end-stage liver failure. After initial TPE, the plasma and RBC protoporphyrin levels decreased from 834.9 to 180.4 μg/dL (normal, ≤1 μg/dL), and from 3,905 to 2,879 μg/dL (normal, ≤80 μg/dL), respectively, without liver function improvement. RCE decreased RBC protoporphyrin levels from 2,879 to 1,225 μg/dL but plasma protoporphyrin increased from 180.4 to 1,044.1 μg/dL, and liver function failed to improve. Additional TPE again stabilized plasma protoporphyrin and improved RBC protoporphyrin levels but the patient ultimately died owing to end-stage liver disease complications. This case illustrates that TPE and RCE may improve the plasma and RBC biochemical markers of EPP activity but liver function abnormalities may persist and patients may still progress to liver failure either because of irreversible liver injury or independent pathobiological factors unrelated to EPP-induced hepatotoxicity.