Phytanic acid storage disease (Refsum's disease): clinical characteristics, pathophysiology and the role of therapeutic apheresis in its management

Safety and tolerance of the ketogenic diet in patients with Zellweger Syndrome

Zellweger Syndrome is a peroxisomal disorder that can lead to elevation of long chain fatty acids and epilepsy, which can be drug resistant. The treatment of drug resistant epilepsy can include the ketogenic diet in appropriately chosen patients. Typically, the ketogenic diet is contraindicated in individuals with defects in fatty acid metabolism because of the diet's reliance on medium and long chain fatty acids. To our knowledge this is the first publication outlining the use of the ketogenic diet in patients with defects in beta oxidation of very long chain fatty acids. We present two patients with Zellweger Syndrome who were placed on a ketogenic diet for drug resistant epilepsy. Safety and tolerance of the ketogenic diet in patients with Zellweger Syndrome.

Disruption of mitochondrial bioenergetics and calcium homeostasis by phytanic acid in the heart: Potential relevance for the cardiomyopathy in Refsum disease

Refsum disease is an inherited peroxisomal disorder caused by severe deficiency of phytanoyl-CoA hydroxylase activity. Affected patients develop severe cardiomyopathy of poorly known pathogenesis that may lead to a fatal outcome. Since phytanic acid (Phyt) concentrations are highly increased in tissues of individuals with this disease, it is conceivable that this branched-chain fatty acid is cardiotoxic. The present study investigated whether Phyt (10-30 μM) could disturb important mitochondrial functions in rat heart mitochondria. We also determined the influence of Phyt (50-100 μM) on cell viability (MTT reduction) in cardiac cells (H9C2). Phyt markedly increased mitochondrial state 4 (resting) and decreased state 3 (ADP-stimulated) and uncoupled (CCCP-stimulated) respirations, besides reducing the respiratory control ratio, ATP synthesis and the activities of the respiratory chain complexes I-III, II, and II-III. This fatty acid also reduced mitochondrial membrane potential and induced swelling in mitochondria supplemented by exogenous Ca²⁺, which were prevented by cyclosporin A alone or combined with ADP, suggesting the involvement of the mitochondrial permeability transition (MPT) pore opening. Mitochondrial NAD(P)H content and Ca²⁺ retention capacity were also decreased by Phyt in the presence of Ca²⁺. Finally, Phyt significantly reduced cellular viability (MTT reduction) in cultured cardiomyocytes. The present data indicate that Phyt, at concentrations found in the plasma of patients with Refsum disease, disrupts by multiple mechanisms mitochondrial bioenergetics and Ca²⁺ homeostasis, which could presumably be involved in the cardiomyopathy of this disease.

Extracorporeal Therapy in Dermatology

Extracorporeal therapy is a treatment modality where human blood undergoes favorable technical modifications and is reintroduced into the same patient. Since the last four decades this technique has been deployed in the management of difficult and refractory disorders in dermatology. Over a period of time newer techniques like immunoadsorption has emerged and opened new vistas in management of morbid dermatoses. In extracorporeal photopheresis a patient's leukocytes are separated and treated outside with Ultra Violet A in presence of 8-methoxypsoralen. Double filtration plasmapheresis and Immunoadsorption are techniques to remove offending immune complexes. They are safe and reduce the need of toxic medications that are conventionally used in recalcitrant skin diseases. In recent years immunoadsorption is emerging as first-line therapy in condition like immunobullous diseases. High cost is one of the important factors limiting their wider use in developing countries like India. Our review discusses different extracorporeal therapies, their applications, recommendations and guidelines based on various clinical trials.

Treatable cerebellar ataxias

Cerebellar ataxic syndrome is a heterogenous class of disorders which can result from a miscellany of causes- genetic or acquired. There are a few metabolic, immune mediated, inflammatory and hereditary causes of ataxia which can be diagnosed from the gamut of possibilities, offering great relief to the ailing patient, their family and the treating physician. A pragmatic algorithm for diagnosing treatable causes of ataxia includes a thorough clinical history, meticulous examination for associated signs and an investigative mind to clinch the diagnosis. With novel diagnostic techniques and targeted therapies, early diagnosis and treatment can lead to favourable outcomes. In this review, diseases presenting predominantly as cerebellar ataxia and are treatable by targeted therapies are discussed.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Application of machine learning algorithms for the differential diagnosis of peroxisomal disorders

We have established diagnostic thresholds of very long-chain fatty acids (VLCFA) for the differential diagnosis of peroxisomal disorders using the machine learning tools. The plasma samples of 131 controls and 90 cases were tested for VLCFA using gas chromatography-mass spectrometry following stable isotope dilution. These data were used to construct association rules and for recursive partitioning. The C26/22 in healthy controls ranged between 0.008 and 0.01. The C26 levels between 1.61 and 3.34 µmol/l and C26/C22 between 0.05 and 0.10 are diagnostic of X-linked adrenoleukodystrophy (X-ALD). Very high levels of C26 (>3.34 µmol/l) and C26/C22 ratio (>0.10) are diagnostic of Zellweger syndrome (ZS). Significant elevation of phytanic acid was observed in Refsum (t = 6.14, P < 0.0001) and Rhizomelic chondrodysplasia punctata (RCDP) (t = 16.72, P < 0.0001). The C26/C22 ratio is slightly elevated in RCDP (t = 2.58, P = 0.01) while no such elevation was observed in Refsum disease (t = 0.86, P = 0.39). The developed algorithm exhibited greater clinical utility (AUC: 0.99-1.00) in differentiating X-ALD, ZS and healthy controls. The algorithm has greater clinical utility in the differential diagnosis of peroxisomal disorders based on VLCFA pattern. Plasmalogens will add additional value in differentiating RCDP and Refsum disease.

Phytyl fatty acid esters in vegetables pose a risk for patients suffering from Refsum's disease

Patients suffering from Refsum’s disease show mutations in the enzyme necessary for the degradation of phytanic acid. Accumulation of this tetramethyl-branched fatty acid in inner organs leads to severe neurological and cardiac dysfunctions which can even result in death. Thus, patients with Refsum’s disease have to follow a specific diet resigning foods with high levels of phytanic acid and trans-phytol like products from ruminant animals with a tolerable daily intake (TDI) of ≤ 10 mg/d. We recently reported the occurrence of phytyl fatty acid esters (PFAE, trans-phytol esterified with a fatty acid) in bell pepper with trans-phytol amounts of up to 5.4 mg/100 g fresh weight (FW). In this study we carried out in vitro-digestion experiments of PFAE with artificial digestion fluids. Our results demonstrate that PFAE actually are a source for bioavailable trans-phytol and thus add to the TDI. Eating only one portion of bell pepper (∼150 g) could therefore lead to exploitation of the TDI of up to 81%. Analysis of additional vegetable matrices showed that also rocket salad with up to 4.2 mg/100 g FW trans-phytol bound in PFAE represents a risk-relevant food for patients with Refsum’s disease and should therefore be taken into account.

Use of plasma exchange or double filtration plasmapheresis to reduce body burden of polychlorinated biphenyls: A pilot trial

The aim of the study was to examine whether plasma exchange (PE) or selective double filtration plasmapheresis (DFPP) is able to reduce the internal Polychlorinated biphenyl (PCB) burden of highly exposed participants of the health effects in high-level exposure to PCB (HELPcB) cohort. HELPcB is a surveillance program for former PCB-exposed workers of a German capacitor recycling company. After comparative evaluation of PE and DFPP in a phase I, DFPP was chosen as method for further treatment. In phase II, five participants underwent DFPP at weekly intervals for the duration of 12 weeks. Six PCB species were selected as indicators and were analyzed in the plasma before and after each treatment and 4 weeks after the last treatment. The PCB levels before and after each DFPP treatment showed a significant reduction in PCB blood levels; however, there was no significant change in PCB levels within the samples collected before each treatment as compared with the samples collected in the following week before treatment. Even the difference between PCB levels at the onset of the study and 4 weeks after the last treatment was not significant. The results of this pilot trial do not encourage further investigations in using therapeutic apheresis to reduce the PCB body burden.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Current concepts in the treatment of hereditary ataxias

Hereditary ataxias (HA) represents an extensive group of clinically and genetically heterogeneous neurodegenerative diseases, characterized by progressive ataxia combined with extra-cerebellar and multi-systemic involvements, including peripheral neuropathy, pyramidal signs, movement disorders, seizures, and cognitive dysfunction. There is no effective treatment for HA, and management remains supportive and symptomatic. In this review, we will focus on the symptomatic treatment of the main autosomal recessive ataxias, autosomal dominant ataxias, X-linked cerebellar ataxias and mitochondrial ataxias. We describe management for different clinical symptoms, mechanism-based approaches, rehabilitation therapy, disease modifying therapy, future clinical trials and perspectives, genetic counseling and preimplantation genetic diagnosis.

Phytyl Fatty Acid Esters in the Pulp of Bell Pepper (Capsicum annuum)

Phytyl fatty acid esters (PFAE) are esters of fatty acids with the isoprenoid alcohol phytol (3,7R,11R,15-tetramethylhexadec-2E-enol). In this study, PFAE were identified and quantified in bell pepper using gas chromatography with mass spectrometry (GC-MS). All red (n = 14) and yellow (n = 6) samples contained six or seven PFAE at 0.9-11.2 mg/100 g fresh weight. By contrast, PFAE were not detected in green bell pepper samples (n = 3). PFAE might eventually be a source for bioavailable phytol, which can be transformed into phytanic acid by humans. Phytanic acid cannot be properly degraded by patients who suffer from Refsum's disease (tolerable daily intake (TDI) ≤ 10 mg of phytanic acid). The phytol moiety of the PFAE (0.4-5.4 mg/100 g fresh weight) would contribute up to ∼50% to the TDI with the consumption of only one portion of bell pepper fruit pulp.

Ataxia

Ataxia is a disorder of balance and coordination resulted from dysfunctions involving cerebellum and its afferent and efferent connections. While a variety of disorders can cause secondary ataxias, the list of genetic causes of ataxias is growing longer. Genetic abnormalities may involve mitochondrial dysfunction, oxidative stress, abnormal mechanisms of DNA repair, possible protein misfolding, and abnormalities in cytoskeletal proteins. Few ataxias are fully treatable while hope for efficacious gene therapy and pharmacotherapy is emerging. A discussion of the ataxias is presented here with brief mention of acquired ataxias, and a greater focus on inherited ataxias.

Treatable causes of cerebellar ataxia

The cerebellar ataxia syndromes are a heterogeneous group of disorders clinically characterized by the presence of cerebellar dysfunction. Initial assessment of patients with progressive cerebellar ataxia is complex because of an extensive list of potential diagnoses. A detailed history and comprehensive examination are required for an accurate diagnosis and hierarchical diagnostic investigations. Although no cure exists for most of these conditions, a small group of metabolic, hereditary, inflammatory, and immune-mediated etiologies of cerebellar ataxia are amenable to disease-modifying, targeted therapies. Over the past years, disease-specific treatments have emerged. Thus, clinicians must become familiar with these disorders because maximal therapeutic benefit is only possible when done early. In this article, we review disorders in which cerebellar ataxia is a prominent clinical feature requiring targeted treatments along with specific management recommendations.

Phytanic acid disturbs mitochondrial homeostasis in heart of young rats: a possible pathomechanism of cardiomyopathy in Refsum disease

Phytanic acid (Phyt) accumulates in tissues and biological fluids of patients affected by Refsum disease. Although cardiomyopathy is an important clinical manifestation of this disorder, the mechanisms of heart damage are poorly known. In the present study, we investigated the in vitro effects of Phyt on important parameters of oxidative stress in heart of young rats. Phyt significantly increased thiobarbituric acid-reactive substances levels (P < 0.001) and carbonyl formation (P < 0.01), indicating that this fatty acid induces lipid and protein oxidative damage, respectively. In contrast, Phyt did not alter sulfhydryl oxidation. Phyt also decreased glutathione (GSH) concentrations (P < 0.05), an important non-enzymatic antioxidant defense. Moreover, Phyt increased 2',7'-dichlorofluorescin oxidation (DCFH) (P < 0.01), reflecting increased reactive species generation. We also found that the induced lipid and protein oxidative damage, as well as the decreased GSH levels and increased DCFH oxidation provoked by this fatty acid were prevented or attenuated by the reactive oxygen species scavengers melatonin, trolox, and GSH, but not by the nitric oxide inhibitor N: (ω)-nitro-L: -arginine methyl ester, suggesting that reactive oxygen species were involved in these effects. Next, we verified that Phyt strongly inhibited NADH-cytochrome c oxidoreductase (complex I-III) activity (P < 0.001) in heart supernatants, and decreased membrane potential and the NAD(P)H pool in heart mitochondria, indicating that Phyt acts as a metabolic inhibitor and as an uncoupler of the electron transport chain. Therefore, it can be presumed that disturbance of cellular energy and redox homeostasis induced by Phyt may possibly contribute to the cardiomyopathy found in patients affected by Refsum disease.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Ichthyoses - Part 1: Differential diagnosis of vulgar ichthyoses and therapeutic options

Ichthyoses are a group of genetic disorders with defective cornification, clinically characterized by scaling of the skin. Additionally, distinctive cutaneous inflammation can often be observed. For most of the patients these diseases lead to a significant restriction in quality of life. The diagnostic criteria include clinical and histological findings, often confirmed by specialized tests. Because many of the ichthyoses are extremely rare, their accurate diagnosis is often carried out in specialized centers. We summarize isolated vulgar and congenital ichthyoses both with and without associated symptoms and focus on the common genetic changes and their clinical phenotype. Specific therapies are still not available for most of these genetic disorders. The use of different topical agents (e. g. urea, retinoids and salicylic acid) and baths followed by mechanical keratolysis (sometimes in combination with systemic retinoids) reduce symptoms. Patients with uncommon congenital ichthyoses often benefit from interdisciplinary management which involves specialized dermatological centers. In this first part of the paper the vulgar ichthyoses as well as the diagnostic and therapeutic options are discussed. The second part focuses on the congenital ichthyoses and their differential diagnosis.

Clinical features and molecular genetics of autosomal recessive cerebellar ataxias

Among the hereditary ataxias, autosomal recessive spinocerebellar ataxias comprise a diverse group of neurodegenerative disorders. Clinical phenotypes vary from predominantly cerebellar syndromes to sensorimotor neuropathy, ophthalmological disturbances, involuntary movements, seizures, cognitive dysfunction, skeletal anomalies, and cutaneous disorders, among others. Molecular pathogenesis also ranges from disorders of mitochondrial or cellular metabolism to impairments of DNA repair or RNA processing functions. Diagnosis can be improved by a systematic approach to the categorisation of these disorders, which is used to direct further, more specific, biochemical and genetic investigations. In this Review, we discuss the clinical characteristics and molecular genetics of the more common autosomal recessive ataxias and provide a framework for assessment and differential diagnosis of patients with these disorders.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.

Refsum's disease may mimic familial Guillain Barre syndrome

Refsum's disease is a rare autosomal recessive disorder with clinical features including retinitis pigmentosa, anosmia, deafness, chronic sensory-motor neuropathy, ataxia and the accumulation of phytanic acid in blood plasma and body tissues. We report the occurrence of Refsum's disease in two sisters, both presenting with acute demyelinating polyneuropathy mimicking the familial Guillain Barre syndrome. Thus, when GBS is suspected, particularly in cases of familial recurrence as well as in atypical cases of acute polyneuropathy, the diagnosis of Refsum's disease should be considered, looking for other features of the disease and, if appropriate, testing plasma phytanic acid levels.

Current therapeutic strategies for patients with polyneuropathies secondary to inherited metabolic disorders

Supportive care, symptomatic treatment, and patient education should be provided for patients with inherited or acquired polyneuropathies. In addition, specific treatment is available for many of the acquired polyneuropathies. Genetic counseling is valuable for many patients with inherited polyneuropathies, but only rarely is specific treatment an option for these patients. However, specific treatments are available for many of the rare and devastating systemic disorders associated with polyneuropathies. Thus, clinicians must promptly diagnose these inherited disorders so that specific treatment may be initiated. The clinical features of these rare inherited disorders are emphasized.

Glucose is toxic to glycosome-deficient trypanosomes

Trypanosomatids, the etiologic agents of sleeping sickness, leishmaniasis, and Chagas' disease, compartmentalize glycolysis within glycosomes, metabolic organelles related to peroxisomes. Here, we identify a trypanosome homologue of PEX14, one of the components of the peroxisomal protein import docking complex. We have used double-stranded RNA interference to target the PEX14 transcript for degradation. Glycosomal matrix protein import was compromised, and both glycolytic bloodstream stage parasites and mitochondrially respiring procyclic stage parasites were killed. Thus, unlike peroxisomes, glycosomes are essential organelles. Surprisingly, procyclic forms, which can grow in the absence of glucose, were killed by PEX14 RNA interference only when simple sugars were present. Thus, interference with glycosome protein import makes glucose toxic to trypanosomes.

Ataxias of childhood

BACKGROUND

This review examines the causes of ataxias in children. It is a relatively common manifestation of neurological diseases in children. The etiology of ataxia covers a broad range, from infections to rare hereditary metabolic diseases. A systematic approach is required to make the correct diagnosis.

REVIEW SUMMARY

The more common causes of ataxias in children are discussed in detail. The importance of recognizing potentially reversible conditions such as vitamin E deficiency and Refsum's disease is stressed. Recent advances in molecular genetics of some of the chronic ataxias are discussed. The importance of categorizing diseases based on the duration of symptoms and associated signs is discussed. Treatment options are mentioned.

CONCLUSION

Ataxia is a common mode of presentation of cerebellar, posterior column, and vestibular disease in children. Awareness of the spectrum of disease entities that cause ataxia in childhood may lead to better diagnosis.