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Chen CT, Shao Z, Fu Z. Dysfunctional peroxisomal lipid metabolisms and their ocular manifestations. Front Cell Dev Biol 2022; 10:982564. [PMID: 36187472 PMCID: PMC9524157 DOI: 10.3389/fcell.2022.982564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Retina is rich in lipids and dyslipidemia causes retinal dysfunction and eye diseases. In retina, lipids are not only important membrane component in cells and organelles but also fuel substrates for energy production. However, our current knowledge of lipid processing in the retina are very limited. Peroxisomes play a critical role in lipid homeostasis and genetic disorders with peroxisomal dysfunction have different types of ocular complications. In this review, we focus on the role of peroxisomes in lipid metabolism, including degradation and detoxification of very-long-chain fatty acids, branched-chain fatty acids, dicarboxylic acids, reactive oxygen/nitrogen species, glyoxylate, and amino acids, as well as biosynthesis of docosahexaenoic acid, plasmalogen and bile acids. We also discuss the potential contributions of peroxisomal pathways to eye health and summarize the reported cases of ocular symptoms in patients with peroxisomal disorders, corresponding to each disrupted peroxisomal pathway. We also review the cross-talk between peroxisomes and other organelles such as lysosomes, endoplasmic reticulum and mitochondria.
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Affiliation(s)
- Chuck T. Chen
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhuo Shao
- Post-Graduate Medical Education, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Metabolic Genetics, the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Genetics Program, North York General Hospital, University of Toronto, Toronto, ON, Canada
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: Zhongjie Fu,
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Characterization of Severity in Zellweger Spectrum Disorder by Clinical Findings: A Scoping Review, Meta-Analysis and Medical Chart Review. Cells 2022; 11:cells11121891. [PMID: 35741019 PMCID: PMC9221082 DOI: 10.3390/cells11121891] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/05/2022] [Accepted: 06/06/2022] [Indexed: 02/04/2023] Open
Abstract
Zellweger spectrum disorder (ZSD) is a rare, debilitating genetic disorder of peroxisome biogenesis that affects multiple organ systems and presents with broad clinical heterogeneity. Although severe, intermediate, and mild forms of ZSD have been described, these designations are often arbitrary, presenting difficulty in understanding individual prognosis and treatment effectiveness. The purpose of this study is to conduct a scoping review and meta-analysis of existing literature and a medical chart review to determine if characterization of clinical findings can predict severity in ZSD. Our PubMed search for articles describing severity, clinical findings, and survival in ZSD resulted in 107 studies (representing 307 patients) that were included in the review and meta-analysis. We also collected and analyzed these same parameters from medical records of 136 ZSD individuals from our natural history study. Common clinical findings that were significantly different across severity categories included seizures, hypotonia, reduced mobility, feeding difficulties, renal cysts, adrenal insufficiency, hearing and vision loss, and a shortened lifespan. Our primary data analysis also revealed significant differences across severity categories in failure to thrive, gastroesophageal reflux, bone fractures, global developmental delay, verbal communication difficulties, and cardiac abnormalities. Univariable multinomial logistic modeling analysis of clinical findings and very long chain fatty acid (VLCFA) hexacosanoic acid (C26:0) levels showed that the number of clinical findings present among seizures, abnormal EEG, renal cysts, and cardiac abnormalities, as well as plasma C26:0 fatty acid levels could differentiate severity categories. We report the largest characterization of clinical findings in relation to overall disease severity in ZSD. This information will be useful in determining appropriate outcomes for specific subjects in clinical trials for ZSD.
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Affiliation(s)
- Robert J Courtney
- Case Eye Institute, Oregon Health and Science University, Portland, OR 97239, USA
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Abstract
Retinitis pigmentosa (RP) refers to a group of inherited retinal diseases with phenotypic and genetic heterogeneity. The pathophysiologic basis of the progressive visual loss in patients with RP is not completely understood but is felt to be due to a primary retinal photoreceptor cell degenerative process mainly affecting the rods of the peripheral retina. In most cases RP is seen in isolation (nonsyndromic), but in some other cases it may be a part of a genetic, metabolic, or neurologic syndrome or disorder. Nyctalopia, or night blindness, is the most common symptom of RP. The classic fundus appearance of RP includes retinal pigment epithelial cell changes resulting in retinal hypo- or hyperpigmentation ("salt-and-pepper"), retinal granularity, and bone spicule formation. The retinal vessels are often narrowed or attenuated and there is a waxy pallor appearance of the optic nerve head. Electroretinography will demonstrate rod and cone photoreceptor cell dysfunction and is a helpful test in the diagnosis and monitoring of patients with RP. A detailed history with pedigree analysis, a complete ocular examination, and the appropriate paraclinical testing should be performed in patients complaining of visual difficulties at night or in dim light. This review discusses the clinical manifestations of RP as well as describing the various systemic diseases, with a special emphasis on neurologic diseases, associated with a pigmentary retinopathy.
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Affiliation(s)
- M Tariq Bhatti
- Department of Ophthalmology, University of FloridaCollege of Medicine, Box 100284 JHMHSC, Gainesville, FL 32610-0284, USA.
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Abstract
The reported incidence of mental retardation in Leber's congenital amaurosis has varied from 10% to 87%. There has been no review of the estimate since it became possible to delineate an increasing number of diagnostic subcategories. In this study, the visual and cognitive development of 38 children with congenital retinal dystrophies has been followed up prospectively. Children with associated disorders in other systems and those with central nervous system malformations or degenerations were significantly more likely to have learning disability than those without additional medical problems. Most subgroups made little or no visual progress with the exception of the group with associated hypoplasia of the cerebellar vermis. The study highlights the importance of using the specialised techniques now available to delineate fully the visual diagnosis and paediatric perspective because of their relevance to cognitive and visual prognosis.
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Affiliation(s)
- M M Black
- Department of Neurology and Developmental Paediatrics, Wolfson Centre, London
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Abstract
Several childhood multisystem disorders with prominent ophthalmological manifestations have been ascribed to the malfunction of the peroxisome, a subcellular organelle. The peroxisomal disorders have been divided into three groups: 1) those that result from defective biogenesis of the peroxisome (Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile Refsum's disease); 2) those that result from multiple enzyme deficiencies (rhizomelic chondrodysplasia punctata); and 3) those that result from a single enzyme deficiency (X-linked adrenoleukodystrophy, primary hyperoxaluria type 1). Zellweger syndrome, the most lethal of the three peroxisomal biogenesis disorders, causes infantile hypotonia, seizures, and death within the first year. Ophthalmic manifestations include corneal opacification, cataract, glaucoma, pigmentary retinopathy and optic atrophy. Neonatal adrenoleukodystrophy and infantile Refsum's disease appear to be genetically distinct, but clinically, biochemically, and pathologically similar to Zellweger syndrome, although milder. Rhizomelic chondrodysplasia punctata, a peroxisomal disorder which results from at least two peroxisomal enzyme deficiencies, presents at birth with skeletal abnormalities and patients rarely survive past one year of age. The most prominent ocular manifestation consists of bilateral cataracts. X-linked (childhood) adrenoleukodystrophy, results from a deficiency of a single peroxisomal enzyme, presents in the latter part of the first decade with behavioral, cognitive and visual deterioration. The vision loss results from demyelination of the entire visual pathway, but the outer retina is spared. Primary hyperoxaluria type 1 manifests parafoveal subretinal pigment proliferation. Classical Refsum's disease may also be a peroxisomal disorder, but definitive evidence is lacking. Early identification of these disorders, which may depend on recognizing the ophthalmological findings, is critical for prenatal diagnosis, treatment, and genetic counselling.
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Affiliation(s)
- S J Folz
- W.K. Kellogg Eye Center, Ann Arbor, Michigan
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Lambert SR, Taylor D, Kriss A. The infant with nystagmus, normal appearing fundi, but an abnormal ERG. Surv Ophthalmol 1989; 34:173-86. [PMID: 2694415 DOI: 10.1016/0039-6257(89)90101-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Many retinal disorders present during infancy with nystagmus, decreased vision, and normal-appearing fundi, but an abnormal ERG. The most common of these disorders are Leber's congenital amaurosis, achromatopsia, and congenital stationary night-blindness. Other disorders with similar ocular manifestations may be associated with a variety of life-threatening systemic abnormalities. This review describes the clinical, electrophysiological, and laboratory findings that can be used to distinguish among these conditions.
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Affiliation(s)
- S R Lambert
- Department of Ophthalmology, Hospital for Sick Children, London, England
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Lambert SR, Kriss A, Taylor D, Coffey R, Pembrey M. Follow-up and diagnostic reappraisal of 75 patients with Leber's congenital amaurosis. Am J Ophthalmol 1989; 107:624-31. [PMID: 2658617 DOI: 10.1016/0002-9394(89)90259-6] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We reexamined 75 children in whom Leber's congenital amaurosis had been previously diagnosed. On review, 30 of these patients had an ocular or systemic disorder other than Leber's congenital amaurosis. The most common of these revised diagnoses were congenital stationary night blindness, achromatopsia, infantile-onset retinitis pigmentosa, Joubert's syndrome, Zellweger syndrome, and infantile Refsum's disease. Of the 45 patients with Leber's congenital amaurosis, mental retardation occurred in six patients, and visual deterioration in six patients. Leber's congenital amaurosis should only be diagnosed if other known ocular and systemic disorders have been carefully excluded.
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Affiliation(s)
- S R Lambert
- Departments of Ophthalmology, Hospitals for Sick Children, London, England
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Wanders RJ, Heymans HS, Schutgens RB, Barth PG, van den Bosch H, Tager JM. Peroxisomal disorders in neurology. J Neurol Sci 1988; 88:1-39. [PMID: 3066850 DOI: 10.1016/0022-510x(88)90203-1] [Citation(s) in RCA: 156] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although peroxisomes were initially believed to play only a minor role in mammalian metabolism, it is now clear that they catalyse essential reactions in a number of different metabolic pathways and thus play an indispensable role in intermediary metabolism. The metabolic pathways in which peroxisomes are involved include the biosynthesis of ether phospholipids and bile acids, the oxidation of very long chain fatty acids, prostaglandins and unsaturated long chain fatty acids and the catabolism of phytanate and (in man) pipecolate and glyoxylate. The importance of peroxisomes in cellular metabolism is stressed by the existence of a group of inherited diseases, the peroxisomal disorders, caused by an impairment in one or more peroxisomal functions. In the last decade our knowledge about peroxisomes and peroxisomal disorders has progressed enormously and has been the subject of several reviews. New developments include the identification of several additional peroxisomal disorders, the discovery of the primary defect in several of these peroxisomal disorders, the recognition of novel peroxisomal functions and the application of complementation analysis to obtain information on the genetic relationship between the different peroxisomal disorders. The peroxisomal disorders recognized at present comprise 12 different diseases, with neurological involvement in 10 of them. These diseases include: (1) those in which peroxisomes are virtually absent leading to a generalized impairment of peroxisomal functions (the cerebro-hepato-renal syndrome of Zellweger, neonatal adrenoleukodystrophy, infantile Refsum disease and hyperpipecolic acidaemia); (2) those in which peroxisomes are present and several peroxisomal functions are impaired (the rhizomelic form of chondrodysplasia punctata, combined peroxisomal beta-oxidation enzyme protein deficiency); and (3) those in which peroxisomes are present and only a single peroxisomal function is impaired (X-linked adrenoleukodystrophy, peroxisomal thiolase deficiency (pseudo-Zellweger syndrome), acyl-CoA oxidase deficiency (pseudo-neonatal adrenoleukodystrophy) and probably, the classic form of Refsum disease.
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Affiliation(s)
- R J Wanders
- Dept. of Pediatrics, University Hospital Amsterdam, The Netherlands
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Torvik A, Torp S, Kase BF, Ek J, Skjeldal O, Stokke O. Infantile Refsum's disease: a generalized peroxisomal disorder. Case report with postmortem examination. J Neurol Sci 1988; 85:39-53. [PMID: 2455020 DOI: 10.1016/0022-510x(88)90034-2] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Infantile Refsum's disease (IRD) is a peroxisomal deficiency disease which is closely related to neonatal adrenoleukodystrophy (NALD) and the Zellweger syndrome (ZS). Recent observations suggest that NALD and ZS are separate genetic disorders but the delimitation towards IRD remains uncertain. We present here the first autopsy report of a patient who was clinically and biochemically diagnosed as having IRD, and we compare the findings with those from NALD and ZS. The main gross and microscopic findings comprised micronodular liver cirrhosis, small hypoplastic adrenals without degenerative changes, and large groups of lipid macrophages in liver, lymph nodes and certain areas of the cerebral white matter. The brain showed no malformations except for a severe hypoplasia of the cerebellar granule layer and ectopic location of the Purkinje cells in the molecular layer. A mild and diffuse reduction of axons and myelin was found in the corpus callosum and periventricular white matter, the corticospinal tracts, and the optic nerves. Large numbers of perivascular macrophages were present in the same areas but there was no active demyelination. The retina and cochlea showed severe degenerative changes. Peripheral nerves, skeletal system and kidneys were normal. Electron microscopy showed characteristic cytoplasmic inclusions with bilamellar profiles in macrophages in the liver, lymph nodes and brain but not in the adrenals. Similar inclusions were found in liver cells and astrocytes. The findings differ from ZS which shows cortical renal cysts, skeletal changes, liver changes, cerebral micropolygyria, neuronal heterotopias, and demyelination of the white matter. Cases with NALD show mild cerebral malformations, active demyelination, degenerative changes of the adrenals, liver changes, and bilamellar electromicroscopic inclusions in macrophages. Our cases thus resembled NALD but lacked active demyelination, cerebral cortical malformations and adrenal degenerative changes. Further autopsy studies will be necessary to determine whether these changes are consistent findings in IRD.
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Affiliation(s)
- A Torvik
- Department of Pathology, Ullevål Hospital, Oslo, Norway
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Affiliation(s)
- A Michalski
- Department of Child Health, Institute of Child Health, London
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Abstract
Peroxisomes have been shown to participate in a variety of pathological processes. Peroxisomal anomalities are central features of Zellweger's cerebro-hepato-renal syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease and several other genetic metabolic disorders (pseudo-Zellweger syndrome, Leber congenital amaurosis, cerebrotendinous xanthomatosis, rhizomelic chondrodysplasia punctata). In disorders with general loss of peroxisomal functions (Zellweger syndrome, neonatal adrenoleukodystrophy, infantile Refsum's disease) an accumulation of very long-chain fatty acids and pathological bile acids are found. Patients have a defective synthesis of plasmalogens and show increased excretion of dicarboxylic acids of medium chain length and of pipecolic acid in the urine. These anomalities which are due to the lack of peroxisomal enzymes, supply the basis for clinical laboratory tests. The study of these peroxisomal disorders has presented valuable information on the normal function of peroxisomes.
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Affiliation(s)
- E Kaiser
- Institut für Medizinische Chemie der Universität Wien, Vienna, Austria
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Barth PG, Schutgens RB, Bakkeren JA, Dingemans KP, Heymans HS, Douwes AC, van der Klei-van Moorsel JM. A milder variant of Zellweger syndrome. Eur J Pediatr 1985; 144:338-42. [PMID: 4076250 DOI: 10.1007/bf00441774] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A 4.5-year-old male patient is described with chorioretinopathy, minor facial anomalies, delayed closure of the fontanel, mental retardation, moderate hypotonia, epilepsy and hepatic fibrosis. Postural control, intentional vocalising and manual dexterity were superior to the performance of patients with classical Zellweger syndrome (ZS). Morphologically distinct peroxisomes were absent in the liver. In blood elevated pipecolic acid levels and abnormal levels of bile acid intermediates were found. The plasmalogen content of erythrocytes was normal. In fibroblasts we found an accumulation of very long chain fatty acids, decreased activity of acyl CoA:dihydroxyacetone phosphate acyltransferase, and impaired de novo biosynthesis of plasmalogens. On the basis of these clinical, ultrastructural and biochemical characteristics we assume that this patient represents a milder variant of the classical cerebro-hepato-renal syndrome of Zellweger.
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Opitz JM. The Zellweger syndrome: Book review and bibliography. The cerebro-hepato-renal syndrome of Zellweger. L.C.P. Govaerts. Nijmegen: Stichting Studentenpers, 1984, 195 pp. ACTA ACUST UNITED AC 1985. [DOI: 10.1002/ajmg.1320220229] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cohen SM, Brown FR, Martyn L, Moser HW, Chen W, Kistenmacher M, Punnett H, de la Cruz ZC, Chan NR, Green WR. Ocular histopathologic and biochemical studies of the cerebrohepatorenal syndrome (Zellweger's syndrome) and its relationship to neonatal adrenoleukodystrophy. Am J Ophthalmol 1983; 96:488-501. [PMID: 6624831 DOI: 10.1016/s0002-9394(14)77913-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The eyes of three infants with cerebrohepatorenal disease (Zellweger's syndrome) who died demonstrated ganglion cell loss, gliosis of the nerve fiber layer and optic nerve, optic atrophy, and changes resembling those of retinitis pigmentosa in the retina and pigment epithelium. Ultrastructural examination showed bileaflet inclusions identical to those seen in neonatal adrenoleukodystrophy in the pigment epithelium and in pigmented macrophages, but these were absent in the cornea. Biochemical analysis of tissues demonstrated an excessive amount of very-long-chain fatty acids in the ocular tissues, an abnormality also found in adrenoleukodystrophy. These histopathologic and biochemical results demonstrated that the cerebrohepatorenal syndrome and neonatal adrenoleukodystrophy are similar in regard to ocular abnormalities and the presence of saturated very-long-chain fatty acids.
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