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Wangler MF, Chao YH, Roth M, Welti R, McNew JA. Drosophila Models Uncover Substrate Channeling Effects on Phospholipids and Sphingolipids in Peroxisomal Biogenesis Disorders. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591192. [PMID: 38746221 PMCID: PMC11092477 DOI: 10.1101/2024.04.26.591192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Peroxisomal Biogenesis Disorders Zellweger Spectrum (PBD-ZSD) disorders are a group of autosomal recessive defects in peroxisome formation that produce a multi-systemic disease presenting at birth or in childhood. Well documented clinical biomarkers such as elevated very long chain fatty acids (VLCFA) are key biochemical diagnostic findings in these conditions. Additional, secondary biochemical alterations such as elevated very long chain lysophosphatidylcholines are allowing newborn screening for peroxisomal disease. In addition, a more widespread impact on metabolism and lipids is increasingly being documented by metabolomic and lipidomic studies. Here we utilize Drosophila models of pex2 and pex16 as well as human plasma from individuals with PEX1 mutations. We identify phospholipid abnormalities in Drosophila larvae and brain characterized by differences in the quantities of phosphatidylcholine (PC) and phosphatidylethanolamines (PE) with long chain lengths and reduced levels of intermediate chain lengths. For diacylglycerol (DAG) the precursor of PE and PC through the Kennedy pathway, the intermediate chain lengths are increased suggesting an imbalance between DAGs and PE and PC that suggests the two acyl chain pools are not in equilibrium. Altered acyl chain lengths are also observed in PE ceramides in the fly models. Interestingly, plasma from human subjects exhibit phospholipid alterations similar to the fly model. Moreover, human plasma shows reduced levels of sphingomyelin with 18 and 22 carbon lengths but normal levels of C24. Our results suggest that peroxisomal biogenesis defects alter shuttling of the acyl chains of multiple phospholipid and ceramide lipid classes, whereas DAG species with intermediate fatty acids are more abundant. These data suggest an imbalance between de novo synthesis of PC and PE through the Kennedy pathway and remodeling of existing PC and PE through the Lands cycle. This imbalance is likely due to overabundance of very long and long acyl chains in PBD and a subsequent imbalance due to substrate channeling effects. Given the fundamental role of phospholipid and sphingolipids in nervous system functions, these observations suggest PBD-ZSD are diseases characterized by widespread cell membrane lipid abnormalities.
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Huang Y, Liu L, Fang F, Zhou H, Liu X. Identification of a novel heterozygous variant in the PEX26 gene in an infant: a case report. Transl Pediatr 2024; 13:192-199. [PMID: 38323187 PMCID: PMC10839275 DOI: 10.21037/tp-23-454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 12/10/2023] [Indexed: 02/08/2024] Open
Abstract
Background The protein PEX26 is involved in the biogenesis and maintenance of peroxisomes, which are organelles within cells. Dysfunction of PEX26 results in peroxisome biogenesis disorders (PBDs) complementation group 8 (CG8), leading to Zellweger spectrum disorders (ZSDs). These disorders present as a syndrome with multiple congenital anomalies, varying in clinical severity. Case Description We present the case of a 7-month-old boy who exhibited hepatic impairment with hepatomegaly, sensorineural hearing loss, developmental delay, abnormal ossification, and mild craniofacial dysmorphology. Tandem mass spectrometry analysis of plasma isolated from whole blood revealed a significant increase in the levels of very long chain fatty acids (VLCFAs) C26:0, C26:0/C22:0, and C24:0/C22:0, consistent with peroxisomal fatty acid oxidation disorder. Exome sequencing identified two variants in the PEX26 gene (c.347T>C and c.616C>T), with the latter being a suspected pathogenic variation. The variant can lead to a defect in the PEX26 gene, resulting in impaired peroxisome biogenesis, β-oxidation of VLCFAs, and disruption of other biochemical pathways. Ultimately, this cascade of events manifests as ZSDs. Currently, symptomatic supportive treatment is the main approach for managing this condition and regular follow-up is being conducted for the patient. Conclusions The present study introduces a novel heterozygous variant comprising two previously unidentified variants in the PEX26 gene, thereby expanding the range of known genetic alterations and highlighting the effectiveness of highly efficient exome sequencing in patients with undetermined multiple system dysfunctions.
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Affiliation(s)
- Yuan Huang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lingling Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Feng Fang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hua Zhou
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinglou Liu
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Yergeau C, Coussa RG, Antaki F, Argyriou C, Koenekoop RK, Braverman NE. Zellweger Spectrum Disorder: Ophthalmic Findings from a New Natural History Study Cohort and Scoping Literature Review. Ophthalmology 2023; 130:1313-1326. [PMID: 37541626 DOI: 10.1016/j.ophtha.2023.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 08/06/2023] Open
Abstract
PURPOSE Individuals with Zellweger spectrum disorder (ZSD) manifest a spectrum of clinical phenotypes but almost all have retinal degeneration leading to blindness. The onset, extent, and progression of retinal findings have not been well described. It is crucial to understand the natural history of vision loss in ZSD to define reliable endpoints for future interventional trials. Herein, we describe ophthalmic findings in the largest number of ZSD patients to date. DESIGN Retrospective review of longitudinal data from medical charts and review of cross-sectional data from the literature. PARTICIPANTS Sixty-six patients with ZSD in the retrospective cohort and 119 patients reported in the literature, divided into 4 disease phenotypes based on genotype or clinical severity. METHODS We reviewed ophthalmology records collected from the retrospective cohort (Clinicaltrials.gov NCT01668186) and performed a scoping review of the literature for ophthalmic findings in patients with ZSD. We extracted available ophthalmic data and analyzed by age and disease severity. MAIN OUTCOME MEASURES Visual acuity (VA), posterior and anterior segment descriptions, nystagmus, refraction, electroretinography findings, visual evoked potentials, and OCT results and images. RESULTS Visual acuity was worse at younger ages in those with severe disease compared with older patients with intermediate to mild disease for all 78 participants analyzed, with a median VA of 0.93 logarithm of the minimum angle of resolution (Snellen 20/320). Longitudinal VA data revealed slow loss over time and legal blindness onset at an average age of 7.8 years. Funduscopy showed retinal pigmentation, macular abnormalities, small or pale optic discs, and attenuated vessels with higher prevalence in milder severity groups and did not change with age. Electroretinography waveforms were diminished in 91% of patients, 46% of which were extinguished and did not change with age. OCT in milder patients revealed schitic changes in 18 of 23 individuals (age range 1.8 to 30 years), with evolution or stable macular edema. CONCLUSIONS In ZSD, VA slowly deteriorates and is associated with disease severity, serial electroretinography is not useful for documenting vision loss progression, and intraretinal schitic changes may be common. Multiple systematic measures are required to assess retinal dystrophy accurately in ZSD, including functional vision measures. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.
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Affiliation(s)
- Christine Yergeau
- Child Health and Human Development Axis, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Razek G Coussa
- Dean McGee Eye Institute, Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma; The Children's Hospital of Oklahoma, Oklahoma City, Oklahoma; Department of Ophthalmology, McGill University, Montreal, Quebec, Canada
| | - Fares Antaki
- Department of Ophthalmology, Centre Hospitalier de l'Université de Montréal (CHUM), Montreal, Quebec, Canada
| | - Catherine Argyriou
- Child Health and Human Development Axis, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada.
| | - Robert K Koenekoop
- Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; Department of Pediatrics, McGill University, Montreal, Quebec, Canada; Department of Paediatric Surgery, McGill University, Montreal, Quebec, Canada
| | - Nancy E Braverman
- Child Health and Human Development Axis, Research Institute of the McGill University Health Center, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada; Department of Pediatrics, McGill University, Montreal, Quebec, Canada
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Swinkels D, Baes M. The essential role of docosahexaenoic acid and its derivatives for retinal integrity. Pharmacol Ther 2023; 247:108440. [PMID: 37201739 DOI: 10.1016/j.pharmthera.2023.108440] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/08/2023] [Accepted: 05/15/2023] [Indexed: 05/20/2023]
Abstract
The fatty acid composition of photoreceptor outer segment (POS) phospholipids diverges from other membranes, being highly enriched in polyunsaturated fatty acids (PUFAs). The most abundant PUFA is docosahexaenoic acid (DHA, C22:6n-3), an omega-3 PUFA that amounts to over 50% of the POS phospholipid fatty acid side chains. Interestingly, DHA is the precursor of other bioactive lipids such as elongated PUFAs and oxygenated derivatives. In this review, we present the current view on metabolism, trafficking and function of DHA and very long chain polyunsaturated fatty acids (VLC-PUFAs) in the retina. New insights on pathological features generated from PUFA deficient mouse models with enzyme or transporter defects and corresponding patients are discussed. Not only the neural retina, but also abnormalities in the retinal pigment epithelium are considered. Furthermore, the potential involvement of PUFAs in more common retinal degeneration diseases such as diabetic retinopathy, retinitis pigmentosa and age-related macular degeneration are evaluated. Supplementation treatment strategies and their outcome are summarized.
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Affiliation(s)
- Daniëlle Swinkels
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium.
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Diagnostic Odyssey in an Adult Patient with Ophthalmologic Abnormalities and Hearing Loss: Contribution of RNA-Seq to the Diagnosis of a PEX1 Deficiency. Int J Mol Sci 2022; 23:ijms232012367. [PMID: 36293220 PMCID: PMC9604267 DOI: 10.3390/ijms232012367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 11/07/2022] Open
Abstract
Peroxisomal biogenesis disorders (PBDs) are a heterogeneous group of genetic diseases. Multiple peroxisomal pathways are impaired, and very long chain fatty acids (VLCFA) are the first line biomarkers for the diagnosis. The clinical presentation of PBDs may range from severe, lethal multisystemic disorders to milder, late-onset disease. The vast majority of PBDs belong to Zellweger Spectrum Disordes (ZSDs) and represents a continuum of overlapping clinical symptoms, with Zellweger syndrome being the most severe and Heimler syndrome the less severe disease. Mild clinical conditions frequently present normal or slight biochemical alterations, making the diagnosis of these patients challenging. In the present study we used a combined WES and RNA-seq strategy to diagnose a patient presenting with retinal dystrophy as the main clinical symptom. Results showed the patient was compound heterozygous for mutations in PEX1. VLCFA were normal, but retrospective analysis of lysosphosphatidylcholines (LPC) containing C22:0–C26:0 species was altered. This simple test could avoid the diagnostic odyssey of patients with mild phenotype, such as the individual described here, who was diagnosed very late in adult life. We provide functional data in cell line models that may explain the mild phenotype of the patient by demonstrating the hypomorphic nature of a deep intronic variant altering PEX1 mRNA processing.
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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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Enns GM, Ammous Z, Himes RW, Nogueira J, Palle S, Sullivan M, Ramirez C. Diagnostic challenges and disease management in patients with a mild Zellweger spectrum disorder phenotype. Mol Genet Metab 2021; 134:217-222. [PMID: 34625341 DOI: 10.1016/j.ymgme.2021.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 11/19/2022]
Abstract
Peroxisome Biogenesis Disorders-Zellweger spectrum disorder (PBD-ZSD) is a rare, autosomal recessive peroxisome biogenesis disorder that presents with variable symptoms. In patients with PBD-ZSD, pathogenic variants in the PEX family of genes disrupt normal peroxisomal function, impairing α- and β-oxidation of very-long-chain fatty acids and synthesis of bile acids, resulting in increased levels of toxic bile acid intermediates and multisystem organ damage. The spectrum of severity in PBD-ZSD is variable, with some patients dying in the first year of life, while others live into adulthood. Symptoms of mild PBD-ZSD include various combinations of developmental delay, craniofacial dysmorphic features, visual impairment, sensorineural hearing loss, liver disease, and adrenal insufficiency. Disease progression in mild PBD-ZSD is generally slow, and may include extended periods of stability in some cases. The presence and extent to which symptoms occur in mild PBD-ZSD represents a diagnostic challenge that can cause delays in diagnosis with potential significant implications related to disease monitoring and treatment. There is some support for the pharmacologic therapies of Lorenzo's oil, docosohexanoic acid, and batyl alcohol in altering symptoms; however, systematic long-term studies are lacking. Cholic acid (CA) therapy has demonstrated treatment efficacy in patients with PBD-ZSD, including decreased toxic bile acid intermediates, transaminase levels, and liver inflammation, with improvement in growth parameters. However, these responses are most apparent in patients diagnosed and treated at a young age. Advanced liver disease may limit the efficacy of CA, underscoring the need to diagnose and treat these patients before significant liver damage and other related complications occur. Here we discuss the signs and symptoms of PBD-ZSD in patients with mild disease, standard diagnostic tools, factors affecting disease management, and available pharmacological interventions.
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Affiliation(s)
| | | | | | - Janaina Nogueira
- The University of Alabama at Birmingham, Children's of Alabama, Birmingham, AL, USA
| | - Sirish Palle
- Oklahoma University Medicine, Oklahoma City, OK, USA
| | - Meghan Sullivan
- MedVal Scientific Information Services, LLC, Princeton, NJ, USA
| | - Charina Ramirez
- University of Texas, Southwestern Medical Center, Children's Medical Center Dallas, Dallas, TX, USA
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Liu Y, Weaver CM, Sen Y, Eitzen G, Simmonds AJ, Linchieh L, Lurette O, Hebert-Chatelain E, Rachubinski RA, Di Cara F. The Nitric Oxide Donor, S-Nitrosoglutathione, Rescues Peroxisome Number and Activity Defects in PEX1G843D Mild Zellweger Syndrome Fibroblasts. Front Cell Dev Biol 2021; 9:714710. [PMID: 34434934 PMCID: PMC8382563 DOI: 10.3389/fcell.2021.714710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/20/2021] [Indexed: 02/04/2023] Open
Abstract
Peroxisome biogenesis disorders (PBDs) are a group of metabolic developmental diseases caused by mutations in one or more genes encoding peroxisomal proteins. Zellweger syndrome spectrum (PBD-ZSS) results from metabolic dysfunction caused by damaged or non-functional peroxisomes and manifests as a multi-organ syndrome with significant morbidity and mortality for which there is no current drug therapy. Mild PBD-ZSS patients can exhibit a more progressive disease course and could benefit from the identification of drugs to improve the quality of life and extend the lifespan of affected individuals. Our study used a high-throughput screen of FDA-approved compounds to identify compounds that improve peroxisome function and biogenesis in human fibroblast cells carrying the mild PBD-ZSS variant, PEX1G843D. Our screen identified the nitrogen oxide donor, S-nitrosoglutathione (GSNO), as a potential therapeutic for this mild form of PBD-ZSS. Further biochemical characterization showed that GSNO enhances both peroxisome number and function in PEX1G843D mutant fibroblasts and leads to increased survival and longer lifespan in an in vivo humanized Drosophila model carrying the PEX1G843D mutation. GSNO is therefore a strong candidate to be translated to clinical trials as a potential therapeutic for mild PBD-ZSS.
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Affiliation(s)
- Yidi Liu
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Ceileigh M Weaver
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, Halifax, NS, Canada
| | - Yarina Sen
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Gary Eitzen
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Simmonds
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Lilliana Linchieh
- Department of Cell Biology, University of Alberta, Edmonton, AB, Canada
| | - Olivier Lurette
- Department of Biology, University of Moncton, Moncton, NB, Canada
| | | | | | - Francesca Di Cara
- Department of Microbiology and Immunology, IWK Research Centre, Dalhousie University, Halifax, NS, Canada
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Benson MD, Papp KM, Casey GA, Radziwon A, St Laurent CD, Doucette LP, MacDonald IM. PEX6 Mutations in Peroxisomal Biogenesis Disorders: An Usher Syndrome Mimic. OPHTHALMOLOGY SCIENCE 2021; 1:100028. [PMID: 36249295 PMCID: PMC9559095 DOI: 10.1016/j.xops.2021.100028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/29/2021] [Accepted: 05/14/2021] [Indexed: 06/16/2023]
Abstract
PURPOSE Peroxisomal biogenesis disorders (PBDs) represent a spectrum of conditions that result in vision loss, sensorineural hearing loss, neurologic dysfunction, and other abnormalities resulting from aberrant peroxisomal function caused by mutations in PEX genes. With no treatments currently available, we sought to investigate the disease mechanism in a patient with a PBD caused by defects in PEX6 and to probe whether overexpression of PEX6 could restore peroxisome function and potentially offer therapeutic benefit. DESIGN Laboratory-based study. PARTICIPANTS A 12-year-old boy sought treatment with hearing loss and retinopathy. After negative results in an Usher syndrome panel, targeted genetic testing revealed compound heterozygous mutations in PEX6. These included a 14-nucleotide deletion (c.802_815del: p.(Asp268Cysfs∗8)) and a milder missense variant (c.35T→C:(p.Phe12Ser)). METHODS Patient-derived skin fibroblasts were cultured, and a PEX6 knockout cell line was developed using clustered regularly interspaced short palindromic repeats and Cas9 technology in HEK293T cells to emulate a more severe disease phenotype. Immunoblot analysis of whole cell lysates was performed to assess peroxisome number. Immunofluorescence studies used antibodies against components of the peroxisomal protein import pathway to interrogate the effects of mutations in PEX6 on protein trafficking. MAIN OUTCOME MEASURES Primary outcome measures were peroxisome abundance and matrix protein import. RESULTS Peroxisome number was not significantly different between control fibroblasts and patient fibroblasts; however, fewer peroxisomes were observed in PEX6 knockout cells compared with wild-type cells (P = 0.04). Analysis by immunofluorescent microscopy showed significantly impaired peroxisomal targeting signal 1- and peroxisomal targeting signal 2-mediated matrix protein import in both patient fibroblasts and PEX6 knockout cells. Overexpressing PEX6 resulted in improved matrix protein import in PEX6 knockout cells. CONCLUSIONS Mutations in PEX6 were responsible for combined hearing loss and retinopathy in our patient. The primary peroxisomal defect in our patient's skin fibroblasts was impaired peroxisomal protein import as opposed to reduction in the number of peroxisomes. Genetic strategies that introduce wild-type PEX6 into cells deficient in PEX6 protein show promise in restoring peroxisome function. Future studies of patient-specific induced pluripotent stem cell-derived retinal pigment epithelium cells may clarify the role of PEX6 in the retina and the potential for gene therapy in these patients.
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Key Words
- CRISPR, clustered regularly interspaced short palindromic repeats
- DTM, docking translocation module
- GFP, green fluorescent protein
- HEK293T, human embryonic kidney 293T
- Hearing loss
- PBD, peroxisomal biogenesis disorder
- PBS, phosphate-buffered saline
- PEX6
- PTS1, peroxisomal targeting signal 1
- PTS2, peroxisomal targeting signal 2
- Peroxisomal biogenesis disorders
- Peroxisome
- RPE, retinal pigment epithelium
- Retinal degeneration
- Usher syndrome
- WT, wild-type
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Affiliation(s)
- Matthew D. Benson
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | - Kimberly M. Papp
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | - Geoffrey A. Casey
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
| | - Alina Radziwon
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | - Chris D. St Laurent
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | - Lance P. Doucette
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
| | - Ian M. MacDonald
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada
- Department of Medical Genetics, University of Alberta, Edmonton, Canada
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Lu P, Ma L, Sun J, Gong X, Cai C. A Chinese newborn with Zellweger syndrome and compound heterozygous mutations novel in the PEX1 gene: a case report and literature review. Transl Pediatr 2021; 10:446-453. [PMID: 33708531 PMCID: PMC7944177 DOI: 10.21037/tp-20-167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
In this study, we report a male newborn with severe Zellweger spectrum disorder (ZSDs) presenting asphyxia, hypotonia, poor feeding, and dysmorphic facial features. Despite intensive supportive treatment, the boy's condition deteriorated progressively. The patient's diagnosis was made by delayed results after his death. His genetic analysis showed that the boy carried novel compound heterozygous mutation in PEX1 gene (c.2050C > T and c.782_783del). We conducted a literature search and identified 316 patients with ZSD caused by mutations in the PEX1 gene. The p.G843D and p.I700Yfs*42 were the most commonly reported mutations. Among the 316 patients, clinical manifestations were available in 265 patients. The segregation of these patients' manifestation showed that patients with missense PEX1 mutations have a milder phenotype than those with truncating mutations, while the common p.G843D mutations are milder than other missense mutations. Nearly all truncating mutations in PEX1 except for those with premature stop codons near the end of the gene were associated with a severe disease phenotype. These results indicated that all domains of PEX1 were important in the maintenance of normal peroxisome function. The correlation between severity of the disease and type of mutations in PEX1 can be helpful in predicting prognosis among patients with ZSD caused by mutated PEX1.
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Affiliation(s)
- Pei Lu
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Li Ma
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jingjing Sun
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaohui Gong
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Cheng Cai
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
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Barillari MR, Karali M, Di Iorio V, Contaldo M, Piccolo V, Esposito M, Costa G, Argenziano G, Serpico R, Carotenuto M, Cappuccio G, Banfi S, Melillo P, Simonelli F. Mild form of Zellweger Spectrum Disorders (ZSD) due to variants in PEX1: Detailed clinical investigation in a 9-years-old female. Mol Genet Metab Rep 2020; 24:100615. [PMID: 32596134 PMCID: PMC7306489 DOI: 10.1016/j.ymgmr.2020.100615] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 06/05/2020] [Accepted: 06/06/2020] [Indexed: 11/27/2022] Open
Abstract
Peroxisomal biogenesis disorders (PBD) are rare autosomal recessive disorders with various degrees of severity caused by hypomorphic mutations in 13 different peroxin (PEX) genes. In this study, we report the clinical and molecular characterization of a 9-years-old female presenting an apparently isolated pre-lingual sensorineural hearing loss (SNHL) and early onset Retinitis Pigmentosa (RP) that may clinically overlap with Usher syndrome. Genetic testing by clinical exome sequencing identified two variants in PEX1: the missense variant c.274G > C; p.(Val92Leu) that was already reported in a PBD patient, and the variant c.2140_2145dup; p.(Ser714_Gln715dup) which is a novel, non-frameshift variant, absent in control databases. On the basis of the molecular analysis, a thorough clinical examination revealed nail and dental abnormalities, a mild cognitive impairment, learning disabilities and poor feeding, apart from the retinal and audiological features initially identified. The clinical and molecular findings led us to the diagnosis of a mild form of PBD. This study further emphasizes that mild forms of PBD can be a differential diagnosis of Usher syndrome and suggests that patients with mild cognitive impairment associated to visual and hearing loss should perform a comprehensive mutation screening that includes PEX genes.
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Key Words
- ABR, Auditory Brainstem Responses
- BCVA, Best Corrected Visual Acuity
- CDI, Children’s Depression Inventory
- ERG, full-field electroretinogram
- Enamel defects
- FAF, color fundus and fundus autofluorescence
- GVF, Goldmann Visual Field
- HS, Heimler syndrome
- Mild Zellweger syndrome
- OCT, optical coherence tomography
- PBD, Peroxisomal biogenesis disorders
- PEX genes
- PEX, peroxin
- PTA, Pure Tone Average
- Peroxisomal biogenesis disorders
- RP, retinitis pigmentosa
- Retinitis pigmentosa
- SNHL, sensorineural hearing loss
- Sensorineural hearing loss
- TEOAE, Transient-Evoked Otoacustic Emission
- VLCFA, Very Long Chain Fatty Acid
- WISC-IV, Wechsler Intelligence Scale for Children (4th Edition)
- ZS, Zellweger Syndrome
- ZSD, Zellweger spectrum disorder
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Affiliation(s)
- Maria Rosaria Barillari
- Division of Phoniatrics and Audiology, Department of Mental and Physical Health and Preventive Medicine, University of Campania "Luigi Vanvitelli", Via L. De Crecchio 4, 80138 Naples, Italy
| | - Marianthi Karali
- Telethon Institute of Genetics and Medicine, Pozzuoli, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via L. De Crecchio 7, 80138 Naples, Italy
| | - Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Via Pansini 5, 80131 Naples, Italy
| | - Maria Contaldo
- Dental Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania “Luigi Vanvitelli”, Via L. De Crecchio 6, 80138 Naples, Italy
| | - Vincenzo Piccolo
- Pediatric Dermatology, Dermatology Unit, University of Campania Luigi Vanvitelli, Via Pansini 5, 80131 Naples, Italy
| | - Maria Esposito
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Via Pansini 5, 80131 Naples, Italy
| | - Giuseppe Costa
- Division of Phoniatrics and Audiology, Department of Mental and Physical Health and Preventive Medicine, University of Campania "Luigi Vanvitelli", Via L. De Crecchio 4, 80138 Naples, Italy
| | - Giuseppe Argenziano
- Pediatric Dermatology, Dermatology Unit, University of Campania Luigi Vanvitelli, Via Pansini 5, 80131 Naples, Italy
| | - Rosario Serpico
- Dental Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania “Luigi Vanvitelli”, Via L. De Crecchio 6, 80138 Naples, Italy
| | - Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", Via Pansini 5, 80131 Naples, Italy
| | - Gerarda Cappuccio
- Telethon Institute of Genetics and Medicine, Pozzuoli, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
- Department of Translational Medicine, Section of Paediatrics, Federico II University, Via Pansini 5, 80131 Naples, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Pozzuoli, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Via L. De Crecchio 7, 80138 Naples, Italy
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Via Pansini 5, 80131 Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Via Pansini 5, 80131 Naples, Italy
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12
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Daich Varela M, Jani P, Zein WM, D'Souza P, Wolfe L, Chisholm J, Zalewski C, Adams D, Warner BM, Huryn LA, Hufnagel RB. The peroxisomal disorder spectrum and Heimler syndrome: Deep phenotyping and review of the literature. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:618-630. [PMID: 32866347 DOI: 10.1002/ajmg.c.31823] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/14/2020] [Accepted: 07/21/2020] [Indexed: 12/20/2022]
Abstract
The spectrum of peroxisomal disorders is wide and comprises individuals that die in the first year of life, as well as people with sensorineural hearing loss, retinal dystrophy and amelogenesis imperfecta. In this article, we describe three patients; two diagnosed with Heimler syndrome and a third one with a mild-intermediate phenotype. We arrived at these diagnoses by conducting complete ophthalmic (National Eye Institute), auditory (National Institute of Deafness and Other Communication Disorders), and dental (National Institute of Dental and Craniofacial Research) evaluations, as well as laboratory and genetic testing. Retinal degeneration with macular cystic changes, amelogenesis imperfecta, and sensorineural hearing loss were features shared by the three patients. Patients A and C had pathogenic variants in PEX1 and Patient B, in PEX6. Besides analyzing these cases, we review the literature regarding mild peroxisomal disorders, their pathophysiology, genetics, differential diagnosis, diagnostic methods, and management. We suggest that peroxisomal disorders are considered in every child with sensorineural hearing loss and retinal degeneration. These patients should have a dental evaluation to rule out amelogenesis imperfecta as well as audiologic examination and laboratory testing including peroxisomal biomarkers and genetic testing. Appropriate diagnosis can lead to better genetic counseling and management of the associated comorbidities.
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Affiliation(s)
- Malena Daich Varela
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Priyam Jani
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Precilla D'Souza
- Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA
| | - Lynne Wolfe
- Undiagnosed Diseases Program, Common Fund, NIH, Bethesda, Maryland, USA
| | - Jennifer Chisholm
- Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, Maryland, USA
| | - Christopher Zalewski
- Audiology Unit, Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, Maryland, USA
| | - David Adams
- Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, Maryland, USA.,Undiagnosed Diseases Program, Common Fund, NIH, Bethesda, Maryland, USA
| | - Blake M Warner
- National Institute of Dental and Craniofacial Research, NIH, Bethesda, Maryland, USA
| | - Laryssa A Huryn
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health (NIH), Bethesda, Maryland, USA
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13
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Cheillan D. Zellweger Syndrome Disorders: From Severe Neonatal Disease to Atypical Adult Presentation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1299:71-80. [PMID: 33417208 DOI: 10.1007/978-3-030-60204-8_6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Zellweger syndrome disorders (ZSD) is the principal group of peroxisomal disorders characterized by a defect of peroxisome biogenesis due to mutations in one of the 13 PEX genes. The clinical spectrum is very large with a continuum from antenatal forms to adult presentation. Whereas biochemical profile in body fluids is classically used for their diagnosis, the revolution of high-throughput sequencing has extended the knowledge about these disorders. The aim of this review is to offer a large panorama on molecular basis, clinical presentation and treatment of ZSD, and to update the diagnosis strategy of these disorders in the era of next-generation sequencing (NGS).
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Affiliation(s)
- David Cheillan
- Inserm U1060 - CarMeN Laboratory, Lyon University, Pierre-Bénite, France.
- Service Biochimie et Biologie Moléculaire Grand Est - Centre de Biologie Est, Hospices Civils de Lyon, Bron, France.
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14
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Gao FJ, Hu FY, Xu P, Qi YH, Li JK, Zhang YJ, Chen F, Chang Q, Song F, Shen SM, Xu GZ, Wu JH. Expanding the clinical and genetic spectrum of Heimler syndrome. Orphanet J Rare Dis 2019; 14:290. [PMID: 31831025 PMCID: PMC6909578 DOI: 10.1186/s13023-019-1243-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 10/29/2019] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Heimler syndrome (HS) is a rare hereditary systemic disorder, partial clinically overlapping with Usher syndrome. So far, our knowledge of HS is very limited, many cases are misdiagnosed or may not even be diagnosed at all. This study aimed to analyze the clinical and genetic characteristics of HS, and to evaluate potential phenotype-genotype correlations. RESULTS Two HS cases caused by PEX1 mutations were identified, and a novel likely pathogenic mutation, PEX1 c.895_896insTATA, was found. The main ophthalmic finding of the two patients was consistent with retinitis pigmentosa accompanied by cystoid macular edema, but short axial length and hyperopia were also observed as two previously unreported ocular phenotypes. Analysis of the literature showed that of the 29 HS patients previously reported, 12 had PEX6 mutations, 10 had PEX1 mutations, two had PEX26 mutations, and the remaining patients were not genetically tested. Three novel genotype-phenotype correlations were revealed from analysis of these patients. First, most genotypes of every HS patient include at least one missense variant; second, at least one mutation in PEX1 or PEX6 gene affects the AAA-ATPase region in every HS patient with retinal dystrophy, suggesting AAA-ATPase region is a hypermutable region in patients with a retinal dystrophy; third, there are no significant differences between PEX1-, PEX6-, and PEX26-associated phenotypes. CONCLUSION Next-generation sequencing is important for the diagnosis of HS. This study expands the clinical and genetic spectrum of HS, and provides additional insights into genotype-phenotype correlations, which is vital for accurate clinical practice, genetic counseling, and pathogenesis studies.
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Affiliation(s)
- Feng-Juan Gao
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang-Yuan Hu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Ping Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Yu-He Qi
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Jian-Kang Li
- BGI-Shenzhen, Shenzhen, China.,Department of Computer Science, City University of Hong Kong, 83 Tat Chee Ave, Kowloon, Hong Kong
| | - Yong-Jin Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang Chen
- BGI-Shenzhen, Shenzhen, China.,Laboratory of Genomics and Molecular Biomedicine, Department of Biology, University of Copenhagen, Copenhagen, Denmark.,Shenzhen Engineering Laboratory for Birth Defects Screening, BGI-Shenzhen, Shenzhen, China
| | - Qing Chang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang Song
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | | | - Ge-Zhi Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China.
| | - Ji-Hong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China.
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15
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Mild Zellweger syndrome due to functionally confirmed novel PEX1 variants. J Appl Genet 2019; 61:87-91. [PMID: 31628608 PMCID: PMC6968987 DOI: 10.1007/s13353-019-00523-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 08/31/2019] [Accepted: 09/11/2019] [Indexed: 01/08/2023]
Abstract
Zellweger spectrum disorders (ZSD) constitute a group of rare autosomal recessive disorders characterized by a defect in peroxisome biogenesis due to mutations in one of 13 PEX genes. The broad clinical heterogeneity especially in late-onset presenting patients and a mild phenotype complicates and delays the diagnostic process. Here, we report a case of mild ZSD, due to novel PEX1 variants. The patient presented with an early hearing loss, bilateral cataracts, and leukodystrophy on magnetic resonance (MR) images. Normal results of serum very-long-chain fatty acids (VLCFA) and phytanic acid were found. Molecular diagnostics were performed to uncover the etiology of the clinical phenotype. Using whole exome sequencing, there have been found two variants in the PEX1 gene-c.3450T>A (p.Cys1150*) and c.1769T>C (p.Leu590Pro). VLCFA measurement in skin fibroblasts and C26:0-lysoPC in dried blood spot therefore was performed. Both results were in line with the diagnosis of ZSD. To conclude, normal results of routine serum VLCFA and branched-chain fatty acid measurement do not exclude mild forms of ZSD. The investigation of C26:0-lysoPC should be included in the diagnostic work-up in patients with cataract, hearing loss, and leukodystrophy on MR images suspected to suffer from ZSD.
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16
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Argyriou C, Polosa A, Cecyre B, Hsieh M, Di Pietro E, Cui W, Bouchard JF, Lachapelle P, Braverman N. A longitudinal study of retinopathy in the PEX1-Gly844Asp mouse model for mild Zellweger Spectrum Disorder. Exp Eye Res 2019; 186:107713. [PMID: 31254513 DOI: 10.1016/j.exer.2019.107713] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/17/2019] [Accepted: 06/25/2019] [Indexed: 02/03/2023]
Abstract
Zellweger Spectrum Disorder (ZSD) is an autosomal recessive disease caused by mutations in any one of 13 PEX genes whose protein products are required for peroxisome assembly. Retinopathy leading to blindness is one of the major untreatable handicaps faced by patients with ZSD but is not well characterized, and the requirement for peroxisomes in retinal health is unknown. To address this, we examined the progression of retinopathy from 2 to 32 weeks of age in our murine model for the common human PEX1-p.Gly843Asp allele (PEX1-p.Gly844Asp) using electrophysiology, histology, immunohistochemistry, electron microscopy, biochemistry, and visual function tests. We found that retinopathy in male and female PEX1-G844D mice was marked by an attenuated cone function and abnormal cone morphology early in life, with gradually decreasing rod function. Structural defects at the inner retina occurred later in the form of bipolar cell degradation (between 13 and 32 weeks). Inner segment disorganization and enlarged mitochondria were seen at 32 weeks, while other inner retinal cells appeared preserved. Visual acuity was diminished by 11 weeks of age, while signal transmission from the retina to the brain was relatively intact from 7 to 32 weeks of age. Molecular analyses showed that PEX1-G844D is a subfunctional but stable protein, contrary to human PEX1-G843D. Finally, C26:0 lysophosphatidylcholine was elevated in the PEX1-G844D retina, while phopshoethanolamine plasmalogen lipids were present at normal levels. These characterization studies identify therapeutic endpoints for future preclinical trials, including improving or preserving the electroretinogram response, improving visual acuity, and/or preventing loss of bipolar cells.
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Affiliation(s)
- Catherine Argyriou
- Department of Human Genetics, McGill University, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Anna Polosa
- Department of Ophthalmology, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Bruno Cecyre
- School of Optometry, Université de Montréal, Pavillon 3744 Jean-Brillant, Bureau 260-39, Montréal, Québec, H3T 1P1, Canada.
| | - Monica Hsieh
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Erminia Di Pietro
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Wei Cui
- Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Jean-François Bouchard
- School of Optometry, Université de Montréal, Pavillon 3744 Jean-Brillant, Bureau 260-39, Montréal, Québec, H3T 1P1, Canada.
| | - Pierre Lachapelle
- Department of Ophthalmology, McGill University, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
| | - Nancy Braverman
- Department of Human Genetics, McGill University, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Child Health and Human Development Program, Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada; Department of Pediatrics, 1001 Decarie Boulevard, Montreal, Quebec, H4A 3J1, Canada.
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17
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Abstract
Peroxisomes play vital roles in a broad spectrum of cellular metabolic pathways. Defects in genes encoding peroxisomal proteins can result in a wide array of disorders, depending upon the metabolic pathways affected. These disorders can be broadly classified into 2 main groups; peroxisome biogenesis disorders (PBDs) and single peroxisomal enzyme deficiencies. Peroxisomal enzyme deficiencies are result of dysfunction of a specific metabolic pathway, while PBDs are due to generalized peroxisomal dysfunction. Mutations in PEX1 gene are the most common cause of PBDs, accounting for two-thirds of cases. Peroxisomal fission defects is a recently recognized entity, included under the subgroup of PBDs. The aim of this article is to provide a comprehensive review on the clinical and neuroimaging spectrum of peroxisomal disorders.
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18
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Wangler MF, Hubert L, Donti TR, Ventura MJ, Miller MJ, Braverman N, Gawron K, Bose M, Moser AB, Jones RO, Rizzo WB, Sutton VR, Sun Q, Kennedy AD, Elsea SH. A metabolomic map of Zellweger spectrum disorders reveals novel disease biomarkers. Genet Med 2018; 20:1274-1283. [PMID: 29419819 PMCID: PMC7605708 DOI: 10.1038/gim.2017.262] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 12/12/2017] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Peroxisome biogenesis disorders-Zellweger spectrum disorders (PBD-ZSD) are metabolic diseases with multisystem manifestations. Individuals with PBD-ZSD exhibit impaired peroxisomal biochemical functions and have abnormal levels of peroxisomal metabolites, but the broader metabolic impact of peroxisomal dysfunction and the utility of metabolomic methods is unknown. METHODS We studied 19 individuals with clinically and molecularly characterized PBD-ZSD. We performed both quantitative peroxisomal biochemical diagnostic studies in parallel with untargeted small molecule metabolomic profiling in plasma samples with detection of >650 named compounds. RESULTS The cohort represented intermediate to mild PBD-ZSD subjects with peroxisomal biochemical alterations on targeted analysis. Untargeted metabolomic profiling of these samples revealed elevations in pipecolic acid and long-chain lysophosphatidylcholines, as well as an unanticipated reduction in multiple sphingomyelin species. These sphingomyelin reductions observed were consistent across the PBD-ZSD samples and were rare in a population of >1,000 clinical samples. Interestingly, the pattern or "PBD-ZSD metabolome" was more pronounced in younger subjects suggesting studies earlier in life reveal larger biochemical changes. CONCLUSION Untargeted metabolomics is effective in detecting mild to intermediate cases of PBD-ZSD. Surprisingly, dramatic reductions in plasma sphingomyelin are a consistent feature of the PBD-ZSD metabolome. The use of metabolomics in PBD-ZSD can provide insight into novel biomarkers of disease.
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Affiliation(s)
- Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.
- Texas Children's Hospital, Houston, Texas, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, Texas, USA.
- Developmental Biology Program, Baylor College of Medicine, Houston, Texas, USA.
| | - Leroy Hubert
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Taraka R Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Marcus J Miller
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Nancy Braverman
- Research Institute of the McGill University Health Center, Montreal, Quebec, Canada
| | - Kelly Gawron
- Department of Nutrition and Food Studies, Montclair State University, Montclair, New Jersey, USA
| | - Mousumi Bose
- Department of Nutrition and Food Studies, Montclair State University, Montclair, New Jersey, USA
| | - Ann B Moser
- Division of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Richard O Jones
- Division of Neurogenetics, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | | | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Qin Sun
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | | | - Sarah H Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.
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19
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Takashima S, Saitsu H, Shimozawa N. Expanding the concept of peroxisomal diseases and efficient diagnostic system in Japan. J Hum Genet 2018; 64:145-152. [PMID: 30237433 DOI: 10.1038/s10038-018-0512-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/21/2018] [Accepted: 08/21/2018] [Indexed: 01/02/2023]
Abstract
The concept of peroxisomal diseases is expanding because of improvements in diagnostic technology based on advanced biochemical analysis and development of next-generation sequencing. For quicker and more accurate diagnosis of as many patients as possible, we developed a new diagnostic system combining the conventional diagnostic system and comprehensive mutational analysis by whole-exome sequencing in Japan. Adrenoleukodystrophy (ALD) is the most common peroxisomal disease. In the cerebral type of ALD, hematopoietic stem cell transplantation is the only treatment in the early stage, and thus prompt diagnosis will improve the prognosis of affected patients. Furthermore, it is also important to identify pre-symptomatic patients by family analysis of probands by providing appropriate disease information and genetic counseling, which will also lead to early intervention. Here, we summarize current information related to peroxisomal diseases and ALD and introduce our efficient diagnostic system for use in Japan, which resulted in the diagnosis of 73 Japanese patients with peroxisome biogenesis disorders, 16 with impaired β-oxidation of fatty acids, three with impaired etherphospholipid biosynthesis, and 191 Japanese families with ALD so far.
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Affiliation(s)
- Shigeo Takashima
- Division of Genomics Research, Life Science Research Center, Gifu University, Gifu, Japan
| | - Hirotomo Saitsu
- Department of Biochemistry, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Nobuyuki Shimozawa
- Division of Genomics Research, Life Science Research Center, Gifu University, Gifu, Japan.
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20
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Bellettato CM, Hubert L, Scarpa M, Wangler MF. Inborn Errors of Metabolism Involving Complex Molecules: Lysosomal and Peroxisomal Storage Diseases. Pediatr Clin North Am 2018; 65:353-373. [PMID: 29502918 DOI: 10.1016/j.pcl.2017.11.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Peroxisomes and lysosomes are distinct subcellular compartments that underlie several pediatric metabolic disorders. Knowledge of their function and cell biology leads to understanding how the disorders result from genetic defects. Diagnostic and therapeutic approaches for the disorders take advantage of the cell biology mechanisms. Whereas peroxisomal disorders are characterized by enzymatic defects in peroxisomal pathways leading to metabolic and lipid changes, lysosomal storage disorders are marked by accumulation of substrates of lysosomal pathways inside the lysosome. The human diseases related to these two organelles are reviewed, focusing on general disease patterns and underlying diagnosis and treatment principles.
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Affiliation(s)
- Cinzia Maria Bellettato
- Brains for Brains Foundation, Department of Women and Children Health, Via Giustiniani 3, Padova 35128, Italy
| | - Leroy Hubert
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Maurizio Scarpa
- Brains for Brains Foundation, Department of Women and Children Health, Via Giustiniani 3, Padova 35128, Italy; Center for Rare Diseases, Department of Pediatric and Adolescent Medicine, Helios Dr. Horst Schmidt Klinik, Ludwig-Erhard-Straße 100, Wiesbaden 65199, Germany; Department of Women and Children Health, University of Padova, Via Giustiniani 3, Padova 35128, Italy
| | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA.
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21
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Wanders RJA. Peroxisomal disorders: Improved laboratory diagnosis, new defects and the complicated route to treatment. Mol Cell Probes 2018; 40:60-69. [PMID: 29438773 DOI: 10.1016/j.mcp.2018.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 02/01/2018] [Accepted: 02/02/2018] [Indexed: 12/15/2022]
Abstract
Peroxisomes catalyze a number of essential metabolic functions of which fatty acid alpha- and beta-oxidation, ether phospholipid biosynthesis, glyoxylate detoxification and bile acid synthesis are the most important. The key role of peroxisomes in humans is exemplified by the existence of a group of peroxisomal disorders, caused by mutations in > 30 different genes which code for proteins with a role in either peroxisome biogenesis or one of the metabolic pathways in peroxisomes. Technological advances in laboratory methods at the metabolite-, enzyme-, and molecular level have not only allowed the identification of new peroxisomal disorders but also new phenotypes associated with already identified genetic defects thus extending the clinical spectrum. Unfortunately, progress in the field of pathogenesis and treatment has lagged behind although there are certainly new and hopeful developments with respect to X-linked adrenoleukodystrophy and hyperoxaluria type 1.
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Affiliation(s)
- Ronald J A Wanders
- Department of Clinical Chemistry, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands; Department of Pediatrics, Laboratory Genetic Metabolic Diseases, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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22
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O'Bryhim BE, Kozel BA, Lueder GT. Novel retinal findings in peroxisomal biogenesis disorders. Ophthalmic Genet 2018; 39:377-379. [PMID: 29377746 DOI: 10.1080/13816810.2018.1430241] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Peroxisomal biogenesis disorders are caused by disruption of long chain fatty acid metabolism due to mutations in PEX genes. Individuals with these disorders often have vision loss due to optic atrophy and pigmentary retinopathy. We report an unusual retinal manifestation of peroxisomal biogenesis disorder.
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Affiliation(s)
- B E O'Bryhim
- a Department of Ophthalmology and Visual Sciences , Washington University in St. Louis , St. Louis , MO , USA
| | - B A Kozel
- b Department of Pediatrics , Washington University School of Medicine , St. Louis , MO , USA.,c National Institutes of Health , National Heart, Lung, and Blood Institute , Bethesda , MD , USA
| | - G T Lueder
- a Department of Ophthalmology and Visual Sciences , Washington University in St. Louis , St. Louis , MO , USA.,d Department of Pediatrics , St. Louis Children's Hospital , St. Louis , MO , USA
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Klouwer FCC, Ferdinandusse S, van Lenthe H, Kulik W, Wanders RJA, Poll-The BT, Waterham HR, Vaz FM. Evaluation of C26:0-lysophosphatidylcholine and C26:0-carnitine as diagnostic markers for Zellweger spectrum disorders. J Inherit Metab Dis 2017; 40:875-881. [PMID: 28677031 DOI: 10.1007/s10545-017-0064-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/31/2017] [Accepted: 06/05/2017] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Zellweger spectrum disorders (ZSD) are a group of genetic metabolic disorders caused by a defect in peroxisome biogenesis. This results in multiple metabolic abnormalities, including elevated very long-chain fatty acid (VLCFA) levels. Elevated levels of C26:0-lysophosphatidylcholine (C26:0-lysoPC) have been shown in dried blood spots (DBS) from ZSD patients. However, little is known about the sensitivity and specificity of this marker and C26:0-carnitine, another VLCFA-marker, in ZSD. We investigated C26:0-lysoPC and C26:0-carnitine as diagnostic markers for ZSD in DBS and fibroblasts. METHODS C26:0-lysoPC levels in 91 DBS from 37 different ZSD patients were determined and compared to the levels in 209 control DBS. C26:0-carnitine levels were measured in 41 DBS from 29 ZSD patients and 97 control DBS. We measured C26:0-lysoPC levels in fibroblasts from 24 ZSD patients and 61 control individuals. RESULTS Elevated C26:0-lysoPC levels (>72 nmol/L) were found in 86/91 ZSD DBS (n=33/37 patients) corresponding to a sensitivity of 89.2%. Median level was 567 nmol/l (range 28-3133 nmol/l). Consistently elevated C26:0-carnitine levels (>0.077 μmol/L) in DBS were found in 16 out of 29 ZSD patients corresponding to a sensitivity of 55.2%. C26:0-lysoPC levels were elevated in 21/24 ZSD fibroblast lines. DISCUSSION C26:0-lysoPC in DBS is a sensitive and useful marker for VLCFA accumulation in patients with a ZSD. C26:0-carnitine in DBS is elevated in some ZSD patients, but is less useful as a diagnostic marker. Implementation of C26:0-lysoPC measurement in the diagnostic work-up when suspecting a ZSD is advised. This marker has the potential to be used for newborn screening for ZSD.
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Affiliation(s)
- Femke C C Klouwer
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Department of Pediatric Neurology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Henk van Lenthe
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Wim Kulik
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Bwee Tien Poll-The
- Department of Pediatric Neurology, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Frédéric M Vaz
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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