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Smith CEL, Laugel-Haushalter V, Hany U, Best S, Taylor RL, Poulter JA, Wortmann SB, Feichtinger RG, Mayr JA, Al Bahlani S, Nikolopoulos G, Rigby A, Black GC, Watson CM, Mansour S, Inglehearn CF, Mighell AJ, Bloch-Zupan A. Biallelic variants in Plexin B2 ( PLXNB2) cause amelogenesis imperfecta, hearing loss and intellectual disability. J Med Genet 2024; 61:689-698. [PMID: 38458752 PMCID: PMC11228227 DOI: 10.1136/jmg-2023-109728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 02/22/2024] [Indexed: 03/10/2024]
Abstract
BACKGROUND Plexins are large transmembrane receptors for the semaphorin family of signalling proteins. Semaphorin-plexin signalling controls cellular interactions that are critical during development as well as in adult life stages. Nine plexin genes have been identified in humans, but despite the apparent importance of plexins in development, only biallelic PLXND1 and PLXNA1 variants have so far been associated with Mendelian genetic disease. METHODS Eight individuals from six families presented with a recessively inherited variable clinical condition, with core features of amelogenesis imperfecta (AI) and sensorineural hearing loss (SNHL), with variable intellectual disability. Probands were investigated by exome or genome sequencing. Common variants and those unlikely to affect function were excluded. Variants consistent with autosomal recessive inheritance were prioritised. Variant segregation analysis was performed by Sanger sequencing. RNA expression analysis was conducted in C57Bl6 mice. RESULTS Rare biallelic pathogenic variants in plexin B2 (PLXNB2), a large transmembrane semaphorin receptor protein, were found to segregate with disease in all six families. The variants identified include missense, nonsense, splicing changes and a multiexon deletion. Plxnb2 expression was detected in differentiating ameloblasts. CONCLUSION We identify rare biallelic pathogenic variants in PLXNB2 as a cause of a new autosomal recessive, phenotypically diverse syndrome with AI and SNHL as core features. Intellectual disability, ocular disease, ear developmental abnormalities and lymphoedema were also present in multiple cases. The variable syndromic human phenotype overlaps with that seen in Plxnb2 knockout mice, and, together with the rarity of human PLXNB2 variants, may explain why pathogenic variants in PLXNB2 have not been reported previously.
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Affiliation(s)
- Claire E L Smith
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Virginie Laugel-Haushalter
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Strasbourg, France
| | - Ummey Hany
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Sunayna Best
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Rachel L Taylor
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
- EMQN CIC, Manchester, UK
| | - James A Poulter
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Saskia B Wortmann
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
- Amalia Children's Hospital, Radboudumc, Nijmegen, The Netherlands
| | - Rene G Feichtinger
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
| | - Johannes A Mayr
- Department of Paediatrics, University Children's Hospital, Salzburger Landesklinken (SALK) and Paracelsus Medical University, Salzburg, Austria
| | - Suhaila Al Bahlani
- Dental & OMFS Clinic, Al Nahdha Hospital, Government of Oman Ministry of Health, Muscat, Oman
| | | | - Alice Rigby
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- School of Dentistry, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Graeme C Black
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Manchester Academic Health Science Centre, Faculty of Biology, Medicine and Health, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Christopher M Watson
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
- North East and Yorkshire Genomic Laboratory Hub, Central Lab, St James's University Hospital, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Sahar Mansour
- Lymphovascular Research Unit, Molecular and Clinical Sciences Research Institute, St George's Hospital, University of London, London, UK
- SW Thames Regional Centre for Genomics, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Chris F Inglehearn
- Institute of Medical Research, St James's University Hospital, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Alan J Mighell
- School of Dentistry, University of Leeds Faculty of Medicine and Health, Leeds, UK
| | - Agnès Bloch-Zupan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U1258, CNRS-UMR7104, Université de Strasbourg, Strasbourg, France
- Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France
- Centre de référence des maladies rares orales et dentaires O-Rares, Filière Santé Maladies rares TETE COU, European Reference Network CRANIO, Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpital Civil, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France
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Thuma TBT, Procopio RA, Jimenez HJ, Gunton KB, Pulido JS. Hypomorphic variants in inherited retinal and ocular diseases: A review of the literature with clinical cases. Surv Ophthalmol 2024; 69:337-348. [PMID: 38036193 DOI: 10.1016/j.survophthal.2023.11.006] [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: 06/20/2022] [Revised: 11/17/2023] [Accepted: 11/20/2023] [Indexed: 12/02/2023]
Abstract
Hypomorphic variants decrease, but do not eliminate, gene function via a reduction in the amount of mRNA or protein product produced by a gene or by production of a gene product with reduced function. Many hypomorphic variants have been implicated in inherited retinal diseases (IRDs) and other genetic ocular conditions; however, there is heterogeneity in the use of the term "hypomorphic" in the scientific literature. We searched for all hypomorphic variants reported to cause IRDs and ocular disorders. We also discuss the presence of hypomorphic variants in the patient population of our ocular genetics department over the past decade. We propose that standardized criteria should be adopted for use of the term "hypomorphic" to describe gene variants to improve genetic counseling and patient care outcomes.
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Affiliation(s)
- Tobin B T Thuma
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | | | - Hiram J Jimenez
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA
| | - Kammi B Gunton
- Department of Pediatric Ophthalmology and Strabismus, Wills Eye Hospital, Philadelphia, PA, USA
| | - Jose S Pulido
- Vickie and Jack Farber Vision Research Center, Wills Eye Hospital, Philadelphia, PA, USA; Retina Service, Wills Eye Hospital, Philadelphia, PA, USA.
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Tang C, Tang F, Cai Y, Tan M, Liu S, Xie T, Jiang X, Huang Y. A pilot study of newborn screening for X-linked adrenoleukodystrophy based on liquid chromatography-tandem mass spectrometry method for detection of C26:0-lysophosphatidylcholine in dried blood spots: Results from 43,653 newborns in a southern Chinese population. Clin Chim Acta 2024; 552:117653. [PMID: 37977233 DOI: 10.1016/j.cca.2023.117653] [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: 04/17/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/19/2023]
Abstract
BACKGROUND X-linked adrenoleukodystrophy (X-ALD) is a rare X-linked disease caused by mutations of the ABCD1 gene. C26:0-lysophosphatidylcholine (C26:0-LPC) has been proved to be an accurate biomarker for X-ALD. This study aims to propose an effective method for screening of X-ALD and to evaluate the performance of the newborn screening (NBS) assay for X-ALD in Guangzhou. METHODS C26:0-LPC in dried blood spots (DBS) was extracted by methanol solution containing isotope-labelled internal standard (C26:0-d4-LPC) and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The sensitivity of the method was assessed in eight male X-ALD patients, two female carriers and 583 healthy controls. The method was conducted on 43,653 newborns. Next generation sequencing was performed on screen-positive samples. Plasma analysis of very long-chain fatty acids and genetic counselling were performed by way of follow-up. RESULTS Elevated C26:0-LPC were 100% sensitive for screening of X-ALD. Of 43,653 newborns, 32 (18 males, 14 females) screened positive. Of these, 14 (43.7%) were identified ABCD1 variants, including seven hemizygous males and seven heterozygous females, and two (6.3%) were diagnosed with other peroxisomal disorders. CONCLUSION The LC-MS/MS method for screening of X-ALD can identify males, heterozygous females and other peroxisomal disorders. The incidence of X-ALD in Guangzhou is not low.
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Affiliation(s)
- Chengfang Tang
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Fang Tang
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Yanna Cai
- Department of Genetics and Endocrinology, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Minyi Tan
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Sichi Liu
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Ting Xie
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Xiang Jiang
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China
| | - Yonglan Huang
- Guangzhou Newborn Screening Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangdong Provincial Clinical Research Center for Child Health, Guangzhou, Guangdong, China.
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Miranda V, Cortez L, Rosmaninho-Salgado J, Ramos F, Paiva C. Ophthalmic Manifestations of Heimler Syndrome in Two Siblings With PEX1 Variants. J Pediatr Ophthalmol Strabismus 2024; 61:59-66. [PMID: 37092661 DOI: 10.3928/01913913-20230220-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
PURPOSE To report two new cases with confirmed diagnosis of Heimler syndrome and describe their systemic and ophthalmic phenotype and visual rehabilitation. METHODS Retrospective review of medical records. RESULTS Both siblings were diagnosed as having sensori-neural hearing loss and retinal dystrophy with exuberant intraretinal cystoid spaces and cone-rod dysfunction. The older sibling also had amelogenesis imperfecta and neither had nail abnormalities. Genetic analysis identified homozygosity for the pathogenic variant c.2528G>A p.(Gly843Asp) in the PEX1 gene in both siblings. The parents were heterozygous carriers of the variant. CONCLUSIONS The authors report a familial case of Heimler syndrome due to biallelic PEX1 pathogenic variants that manifested as macular dystrophy characterized by cone-rod dysfunction and complicated by intraretinal cystoid spaces. Review of the literature shows that ocular phenotype is variable in patients with Heimler syndrome. [J Pediatr Ophthalmol Strabismus. 2024;61(1):59-66.].
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Yu M, Zhang M, Chen Q, Huang T, Gan R, Yan X. A novel compound heterozygous PEX1 variant in Heimler syndrome. Exp Eye Res 2023; 237:109688. [PMID: 37871882 DOI: 10.1016/j.exer.2023.109688] [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: 07/06/2023] [Revised: 10/14/2023] [Accepted: 10/20/2023] [Indexed: 10/25/2023]
Abstract
Heimler syndrome (HS) is a rare autosomal recessive hereditary disease that is caused by biallelic variants in peroxisomal biogenic factor 1 gene (PEX1), peroxisomal biogenic factor 6 gene (PEX6) or peroxisomal biogenic factor 26 gene (PEX26), resulting in intracellular peroxisomal dysfunction (PBDs). We report a patient with HS with a new compound heterozygous PEX1 variant. Exon sequencing was used to screen pathologic variants in the patient. Retinal characteristics and serum metabolome alterations were evaluated. Scanning laser ophthalmoscope showed a large area of retinal choroidal atrophy at the posterior pole of the retina, with scattered patchy subretinal pigmentation. Optical coherence tomography showed fovea atrophy accompanied by retinal retinoschisis in the right eye and macular retinoschisis and edema in the left eye. The electroretinogram showed obviously reduced amplitudes of a-waves and b-waves under photopic and scotopic conditions in both eyes. Visual field tests showed a reduced central visual field in both eyes. Exon sequencing identified the compound heterozygous variant including c.2966T > C and c.1670+1G > T of the PEX1 gene, with the latter being novel. Nontargeted determination of total lipid metabolites and targeted determination of medium- and long-chain fatty acids in the serum of the patient and his healthy sibling were tested. This study identified a new compound heterozygous PEX1 variant, expanding our understanding of phenotypes in HS.
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Affiliation(s)
- Mingyu Yu
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Min Zhang
- School of Medicine, Anhui University of Science and Technology, Huainan, China
| | - Qingshan Chen
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Tao Huang
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Run Gan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, China
| | - Xiaohe Yan
- Shenzhen Eye Hospital, Jinan University, Shenzhen Eye Institute, Shenzhen, 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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Liang JS, Hung KL, Lin LJ, Ong WP, Keng WT, Lu JF. Novel PEX1 mutations in fibroblasts from children with Zellweger spectrum disorders exhibit temperature sensitive characteristics. Epilepsy Behav 2023; 145:109266. [PMID: 37385119 DOI: 10.1016/j.yebeh.2023.109266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 07/01/2023]
Abstract
Zellweger spectrum disorders (ZSD) are rare autosomal recessive disorders caused by defects in peroxisome biogenesis factor (PEX; peroxin) genes leading to impaired transport of peroxisomal proteins with peroxisomal targeting signals (PTS). Four patients, including a pair of homozygotic twins, diagnosed as ZSD by genetic study with different clinical presentations and outcomes as well as various novel mutations are described here. A total of 3 novel mutations, including a nonsense, a frameshift, and a splicing mutation, in PEX1 from ZSD patients were identified and unequivocally confirmed that the p.Ile989Thr mutant PEX1 exhibited temperature-sensitive characteristics and is associated with milder ZSD. The nature of the p.Ile989Thr mutant exhibited different characteristics from that of the other previously identified temperature-sensitive p.Gly843Asp PEX1 mutant. Transcriptome profiles under nonpermissive vs. permissive conditions were explored to facilitate the understanding of p.Ile989Thr mutant PEX1. Further investigation of molecular mechanisms may help to clarify potential genetic causes that could modify the clinical presentation of ZSD.
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Affiliation(s)
- Jao-Shwann Liang
- Departments of Pediatrics, Far Eastern Memorial Hospital, New Taipei City, Taiwan; Department of Nursing, Asia Eastern University of Science and Technology, New Taipei City, Taiwan
| | - Kun-Long Hung
- Departments of Pediatrics, Fu Jen Catholic University Hospital, New Taipei City, Taiwan; School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Li-Ju Lin
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan
| | - Winnie Peitee Ong
- Department of Genetics, Kuala Lumpur Hospital, Kuala Lumpur, Malaysia
| | - Wee Teik Keng
- Department of Genetics, Kuala Lumpur Hospital, Kuala Lumpur, Malaysia
| | - Jyh-Feng Lu
- School of Medicine, Fu Jen Catholic University, New Taipei City, Taiwan.
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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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Cellular and Molecular Mechanisms of Pathogenesis Underlying Inherited Retinal Dystrophies. Biomolecules 2023; 13:biom13020271. [PMID: 36830640 PMCID: PMC9953031 DOI: 10.3390/biom13020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are congenital retinal degenerative diseases that have various inheritance patterns, including dominant, recessive, X-linked, and mitochondrial. These diseases are most often the result of defects in rod and/or cone photoreceptor and retinal pigment epithelium function, development, or both. The genes associated with these diseases, when mutated, produce altered protein products that have downstream effects in pathways critical to vision, including phototransduction, the visual cycle, photoreceptor development, cellular respiration, and retinal homeostasis. The aim of this manuscript is to provide a comprehensive review of the underlying molecular mechanisms of pathogenesis of IRDs by delving into many of the genes associated with IRD development, their protein products, and the pathways interrupted by genetic mutation.
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Ultra-Widefield Imaging of Retinal Flecks and Corresponding Subretinal Hyperreflective Deposits in Heimler Syndrome. Retina 2023; 43:e1-e2. [PMID: 36542084 DOI: 10.1097/iae.0000000000003581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Masunova N, Tereschenko M, Alexandrov G, Spirina L, Tarasenko N. Crucial Role of microRNAs as New Targets for Amelogenesis Disorders Detection. Curr Drug Targets 2023; 24:1139-1149. [PMID: 37936447 DOI: 10.2174/0113894501257011231030161427] [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: 04/19/2023] [Revised: 09/21/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023]
Abstract
INTRODUCTION Amelogenesis imperfecta (AI) refers to a heterogeneous group of conditions with multiple factors which contribute to the hypomineralisation of enamel. Preventive measures are necessary to predict this pathology. Prospects for preventive medicine are closely related to the search for new informative methods for diagnosing a human disease. MicroRNAs are prominent for the non-invasive diagnostic platform. THE AIM OF THE STUDY The aim of the review is to review the heterogeneous factors involved in amelogenesis and to select the microRNA panel associated with the AI type. METHODS We used DIANA Tools (algorithms, databases and software) for interpreting and archiving data in a systematic framework ranging from the analysis of expression regulation from deep sequencing data to the annotation of miRNA regulatory elements and targets (https://dianalab. e-ce.uth.gr/). In our study, based on a gene panel associated with the AI types, twenty-four miRNAs were identified for the hypoplastic type (supplement), thirty-five for hypocalcified and forty-- nine for hypomaturation AI. The selection strategy included the microRNA search with multiple targets using the AI type's gene panel. RESULTS Key proteins, calcium-dependent and genetic factors were analysed to reveal their role in amelogenesis. The role of extracellular non-coding RNA sequences with multiple regulatory functions seems to be the most attractive. We chose the list of microRNAs associated with the AI genes. We found four microRNAs (hsa-miR-27a-3p, hsa-miR-375, hsa-miR-16-5p and hsamiR- 146a-5p) for the gene panel, associated with the hypoplastic type of AI; five microRNAs (hsa- miR-29c-3p, hsa-miR-124-3p, hsa-miR-1343-3p, hsa-miR-335-5p, and hsa-miR-16-5p - for hypocalcified type of AI, and seven ones (hsa-miR-124-3p, hsa-miR-147a, hsa-miR-16-5p, hsamiR- 429, hsa-let-7b-5p, hsa-miR-146a-5p, hsa-miR-335-5p) - for hypomaturation. It was revealed that hsa-miR-16-5p is included in three panels specific for both hypoplastic, hypocalcified, and hypomaturation types. Hsa-miR-146a-5p is associated with hypoplastic and hypomaturation type of AI, which is associated with the peculiarities of the inflammatory response immune response. In turn, hsa-miR-335-5p associated with hypocalcified and hypomaturation type of AI. CONCLUSION Liquid biopsy approaches are a promising way to reduce the economic cost of treatment for these patients in modern healthcare. Unique data exist about the role of microRNA in regulating amelogenesis. The list of microRNAs that are associated with AI genes and classified by AI types has been uncovered. The target gene analysis showed the variety of functions of selected microRNAs, which explains the multiple heterogeneous mechanisms in amelogenesis. Predisposition to mineralisation problems is a programmed event. Many factors determine the manifestation of this problem. Additionally, it is necessary to remember the variable nature of the changes, which reduces the prediction accuracy. Therefore, models based on liquid biopsy and microRNAs make it possible to take into account these factors and their influence on the mineralisation. The found data needs further investigation.
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Affiliation(s)
- Nadezhda Masunova
- Siberian State Medical University of the Ministry of Health of Russia, 634050, Tomsk, Russia
| | - Maria Tereschenko
- Siberian State Medical University of the Ministry of Health of Russia, 634050, Tomsk, Russia
| | - Georgy Alexandrov
- Siberian State Medical University of the Ministry of Health of Russia, 634050, Tomsk, Russia
| | - Liudmila Spirina
- Siberian State Medical University of the Ministry of Health of Russia, 634050, Tomsk, Russia
- Cancer Research Institute, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
| | - Natalia Tarasenko
- Siberian State Medical University of the Ministry of Health of Russia, 634050, Tomsk, Russia
- Research Institute of Medical Genetics, Tomsk National Research Medical Center of the Russian Academy of Sciences, Tomsk, Russia
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12
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Wanders RJA, Baes M, Ribeiro D, Ferdinandusse S, Waterham HR. The physiological functions of human peroxisomes. Physiol Rev 2023; 103:957-1024. [PMID: 35951481 DOI: 10.1152/physrev.00051.2021] [Citation(s) in RCA: 47] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Peroxisomes are subcellular organelles that play a central role in human physiology by catalyzing a range of unique metabolic functions. The importance of peroxisomes for human health is exemplified by the existence of a group of usually severe diseases caused by an impairment in one or more peroxisomal functions. Among others these include the Zellweger spectrum disorders, X-linked adrenoleukodystrophy, and Refsum disease. To fulfill their role in metabolism, peroxisomes require continued interaction with other subcellular organelles including lipid droplets, lysosomes, the endoplasmic reticulum, and mitochondria. In recent years it has become clear that the metabolic alliance between peroxisomes and other organelles requires the active participation of tethering proteins to bring the organelles physically closer together, thereby achieving efficient transfer of metabolites. This review intends to describe the current state of knowledge about the metabolic role of peroxisomes in humans, with particular emphasis on the metabolic partnership between peroxisomes and other organelles and the consequences of genetic defects in these processes. We also describe the biogenesis of peroxisomes and the consequences of the multiple genetic defects therein. In addition, we discuss the functional role of peroxisomes in different organs and tissues and include relevant information derived from model systems, notably peroxisomal mouse models. Finally, we pay particular attention to a hitherto underrated role of peroxisomes in viral infections.
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Affiliation(s)
- Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Daniela Ribeiro
- Institute of Biomedicine (iBiMED) and Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, Amsterdam, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Department of Clinical Chemistry, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,Department of Pediatrics, Emma Children's Hospital, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands.,United for Metabolic Diseases, Amsterdam, The Netherlands
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13
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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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14
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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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15
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Cell Type-Selective Loss of Peroxisomal β-Oxidation Impairs Bipolar Cell but Not Photoreceptor Survival in the Retina. Cells 2022; 11:cells11010161. [PMID: 35011723 PMCID: PMC8750404 DOI: 10.3390/cells11010161] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/20/2021] [Accepted: 12/29/2021] [Indexed: 12/12/2022] Open
Abstract
Retinal degeneration is a common feature in peroxisomal disorders leading to blindness. Peroxisomes are present in the different cell types of the retina; however, their precise contribution to retinal integrity is still unclear. We previously showed that mice lacking the central peroxisomal β-oxidation enzyme, multifunctional protein 2 (MFP2), develop an early onset retinal decay including photoreceptor cell death. To decipher the function of peroxisomal β-oxidation in photoreceptors, we generated cell type selective Mfp2 knockout mice, using the Crx promotor targeting photoreceptors and bipolar cells. Surprisingly, Crx-Mfp2−/− mice maintained photoreceptor length and number until the age of 1 year. A negative electroretinogram was indicative of preserved photoreceptor phototransduction, but impaired downstream bipolar cell signaling from the age of 6 months. The photoreceptor ribbon synapse was affected, containing free-floating ribbons and vesicles with altered size and density. The bipolar cell interneurons sprouted into the ONL and died. Whereas docosahexaenoic acid levels were normal in the neural retina, levels of lipids containing very long chain polyunsaturated fatty acids were highly increased. Crx-Pex5−/− mice, in which all peroxisomal functions are inactivated in photoreceptors and bipolar cells, developed the same phenotype as Crx-Mfp2−/− mice. In conclusion, the early photoreceptor death in global Mfp2−/− mice is not driven cell autonomously. However, peroxisomal β-oxidation is essential for the integrity of photoreceptor ribbon synapses and of bipolar cells.
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16
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Argyriou C, Polosa A, Song JY, Omri S, Steele B, Cécyre B, McDougald DS, Di Pietro E, Bouchard JF, Bennett J, Hacia JG, Lachapelle P, Braverman NE. AAV-mediated PEX1 gene augmentation improves visual function in the PEX1-Gly844Asp mouse model for mild Zellweger spectrum disorder. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 23:225-240. [PMID: 34703844 PMCID: PMC8516995 DOI: 10.1016/j.omtm.2021.09.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 09/01/2021] [Indexed: 12/01/2022]
Abstract
Patients with Zellweger spectrum disorder (ZSD) commonly present with vision loss due to mutations in PEX genes required for peroxisome assembly and function. Here, we evaluate PEX1 retinal gene augmentation therapy in a mouse model of mild ZSD bearing the murine equivalent (PEX1-p[Gly844Asp]) of the most common human mutation. Experimental adeno-associated virus 8.cytomegalovirus.human PEX1.hemagglutinin (AAV8.CMV.HsPEX1.HA) and control AAV8.CMV.EGFP vectors were administered by subretinal injection in contralateral eyes of early (5-week-old)- or later (9-week-old)-stage retinopathy cohorts. HsPEX1.HA protein was expressed in the retina with no gross histologic side effects. Peroxisomal metabolic functions, assessed by retinal C26:0 lysophosphatidylcholine (lyso-PC) levels, were partially normalized after therapeutic vector treatment. Full-field flash electroretinogram (ffERG) analyses at 8 weeks post-injection showed a 2-fold improved retinal response in the therapeutic relative to control vector-injected eyes. ffERG improved by 1.6- to 2.5-fold in the therapeutic vector-injected eyes when each cohort reached 25 weeks of age. At 32 weeks of age, the average ffERG response was double in the therapeutic relative to control vector-injected eyes in both cohorts. Optomotor reflex analyses trended toward improvement. These proof-of-concept studies represent the first application of gene augmentation therapy to treat peroxisome biogenesis disorders and support the potential for retinal gene delivery to improve vision in these patients.
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Affiliation(s)
- Catherine Argyriou
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Anna Polosa
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Ji Yun Song
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samy Omri
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Bradford Steele
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bruno Cécyre
- School of Optometry, Université de Montréal, Montreal, QC, Canada
| | - Devin S McDougald
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Erminia Di Pietro
- Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | | | - Jean Bennett
- Center for Advanced Retinal and Ocular Therapeutics, F.M. Kirby Center for Molecular Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph G Hacia
- Department of Biochemistry and Molecular Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Pierre Lachapelle
- Department of Ophthalmology & Visual Sciences, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Nancy E Braverman
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Research Institute of the McGill University Health Centre, Montreal, QC, Canada
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17
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Herijgers D, Denayer E, Balikova I, Witters P, Jacob J, Casteels I. Two siblings with Heimler syndrome caused by PEX1 variants: follow-up of ophthalmologic findings. Ophthalmic Genet 2021; 42:480-485. [PMID: 33955814 DOI: 10.1080/13816810.2021.1923033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Heimler syndrome (OMIM number #234580 and #616617) is a rare condition comprising sensorineural hearing loss (SNHL), nail abnormalities and amelogenesis imperfecta. In addition, patients with this syndrome can have retinal dystrophies. Heimler syndrome is caused by bi-allelic pathogenic variants in the PEX1 or PEX6 gene. Only few patients with this syndrome have been reported. We hereby describe two siblings with genetically confirmed Heimler syndrome and provide imaging of the ocular phenotype. MATERIALS AND METHODS The medical records of the siblings were reviewed retrospectively. RESULTS Both brother and sister were diagnosed with SNHL and amelogenesis imperfecta of the permanent teeth; one of the affected siblings also had nail abnormalities. Both patients presented to the ophthalmology department with suboptimal visual acuity, fundus abnormalities and intraretinal cystoid spaces. Full-field electroretinogram revealed a cone-rod dysfunction. A genetic analysis revealed a homozygous likely pathogenic variant c.3077 T > C (p.Leu1026Pro) in the PEX1 gene in both siblings. The parents are heterozygous carriers of the variant. CONCLUSION We recommend performing regular ophthalmic examination in patients with Heimler syndrome since the ophthalmic manifestations can manifest later in life. Our patients presented with cone-rod dystrophy and intraretinal cystoid spaces. Review of the literature shows that the ocular phenotype can be very variable in patients with Heimler syndrome.
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Affiliation(s)
- Dorien Herijgers
- Department of Ophthalmology, University Hospital Leuven, Leuven, Belgium
| | - Ellen Denayer
- Department of Human Genetics, University Hospital Leuven, Leuven, Belgium
| | - Irina Balikova
- Department of Ophthalmology, University Hospital Leuven, Leuven, Belgium
| | - Peter Witters
- Department of Pediatrics, Metabolic Center, University Hospital Leuven, Leuven, Belgium.,Department of Development and Regeneration, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Julie Jacob
- Department of Ophthalmology, University Hospital Leuven, Leuven, Belgium
| | - Ingele Casteels
- Department of Ophthalmology, University Hospital Leuven, Leuven, Belgium
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18
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Identification of a Homozygous PEX26 Mutation in a Heimler Syndrome Patient. Genes (Basel) 2021; 12:genes12050646. [PMID: 33926089 PMCID: PMC8146857 DOI: 10.3390/genes12050646] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/26/2021] [Accepted: 04/26/2021] [Indexed: 12/30/2022] Open
Abstract
This study aimed to identify the molecular genetic etiology of an 8-year-old boy with amelogenesis imperfecta in permanent dentition. Bilateral cochlear implants were placed due to sensorineural hearing loss, and there was no other family member with a similar phenotype. Peripheral blood samples were collected with the understanding and written consent of the participating family members. A constitutional chromosome study was performed for the proband. Genomic DNA was isolated, and whole exome sequencing was performed. A series of bioinformatic analyses were performed with the obtained paired-end sequencing reads, and the variants were filtered and annotated with dbSNP147. There was no abnormality in the constitutional chromosome study. Whole exome sequencing analysis with trio samples identified a homozygous mutation (c.506T>C, p. (Leu169Pro)) in the PEX26 gene. We verified “temperature sensitivity (ts)” of patient-derived Pex26-L169P by expression in pex26 CHO mutant ZP167 cells to determine the effect of the L169P mutation on Pex26 function. The L169P mutation causes a mild ts-cellular phenotype representing the decreased peroxisomal import of catalase. This study supports the finding that the recessive mutations in PEX26 are associated with Heimler syndrome and demonstrates the importance of an early and correct diagnosis.
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19
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Das Y, Swinkels D, Baes M. Peroxisomal Disorders and Their Mouse Models Point to Essential Roles of Peroxisomes for Retinal Integrity. Int J Mol Sci 2021; 22:ijms22084101. [PMID: 33921065 PMCID: PMC8071455 DOI: 10.3390/ijms22084101] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 12/31/2022] Open
Abstract
Peroxisomes are multifunctional organelles, well known for their role in cellular lipid homeostasis. Their importance is highlighted by the life-threatening diseases caused by peroxisomal dysfunction. Importantly, most patients suffering from peroxisomal biogenesis disorders, even those with a milder disease course, present with a number of ocular symptoms, including retinopathy. Patients with a selective defect in either peroxisomal α- or β-oxidation or ether lipid synthesis also suffer from vision problems. In this review, we thoroughly discuss the ophthalmological pathology in peroxisomal disorder patients and, where possible, the corresponding animal models, with a special emphasis on the retina. In addition, we attempt to link the observed retinal phenotype to the underlying biochemical alterations. It appears that the retinal pathology is highly variable and the lack of histopathological descriptions in patients hampers the translation of the findings in the mouse models. Furthermore, it becomes clear that there are still large gaps in the current knowledge on the contribution of the different metabolic disturbances to the retinopathy, but branched chain fatty acid accumulation and impaired retinal PUFA homeostasis are likely important factors.
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20
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Das Y, Swinkels D, Kocherlakota S, Vinckier S, Vaz FM, Wever E, van Kampen AHC, Jun B, Do KV, Moons L, Bazan NG, Van Veldhoven PP, Baes M. Peroxisomal Multifunctional Protein 2 Deficiency Perturbs Lipid Homeostasis in the Retina and Causes Visual Dysfunction in Mice. Front Cell Dev Biol 2021; 9:632930. [PMID: 33604342 PMCID: PMC7884615 DOI: 10.3389/fcell.2021.632930] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/11/2021] [Indexed: 01/09/2023] Open
Abstract
Patients lacking multifunctional protein 2 (MFP2), the central enzyme of the peroxisomal β-oxidation pathway, develop retinopathy. This pathway is involved in the metabolism of very long chain (VLCFAs) and polyunsaturated (PUFAs) fatty acids, which are enriched in the photoreceptor outer segments (POS). The molecular mechanisms underlying the retinopathy remain, however, elusive. Here, we report that mice with MFP2 inactivation display decreased retinal function already at the age of 3 weeks, which is accompanied by a profound shortening of the photoreceptor outer and inner segments, but with preserved photoreceptor ultrastructure. Furthermore, MFP2 deficient retinas exhibit severe changes in gene expression with downregulation of genes involved in the phototransduction pathway and upregulation of inflammation related genes. Lipid profiling of the mutant retinas revealed a profound reduction of DHA-containing phospholipids. This was likely due to a hampered systemic supply and retinal traffic of this PUFA, although we cannot exclude that the local defect of peroxisomal β-oxidation contributes to this DHA decrease. Moreover, very long chain PUFAs were also reduced, with the exception of those containing ≥ 34 carbons that accumulated. The latter suggests that there is an uncontrollable elongation of retinal PUFAs. In conclusion, our data reveal that intact peroxisomal β-oxidation is indispensable for retinal integrity, most likely by maintaining PUFA homeostasis.
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Affiliation(s)
- Yannick Das
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Daniëlle Swinkels
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Sai Kocherlakota
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | - Stefan Vinckier
- Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology, KU Leuven-VIB, Leuven, Belgium
| | - Frédéric M Vaz
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry and Pediatrics, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center (UMC), Amsterdam, Netherlands
| | - Eric Wever
- Laboratory of Genetic Metabolic Diseases, Department of Clinical Chemistry and Pediatrics, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands.,Core Facility Metabolomics, Amsterdam University Medical Center (UMC), Amsterdam, Netherlands.,Bioinformatics Laboratory, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands
| | - Antoine H C van Kampen
- Bioinformatics Laboratory, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam University Medical Center (UMC), University of Amsterdam, Amsterdam, Netherlands.,Biosystems Data Analysis, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Bokkyoo Jun
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, United States
| | - Khanh V Do
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, United States
| | - Lieve Moons
- Animal Physiology and Neurobiology, Department of Biology, KU Leuven, Leuven, Belgium
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, LA, United States
| | - Paul P Van Veldhoven
- Lipid Biochemistry and Protein Interactions (LIPIT), Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Myriam Baes
- Laboratory of Cell Metabolism, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
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21
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Tatour Y, Ben-Yosef T. Syndromic Inherited Retinal Diseases: Genetic, Clinical and Diagnostic Aspects. Diagnostics (Basel) 2020; 10:diagnostics10100779. [PMID: 33023209 PMCID: PMC7600643 DOI: 10.3390/diagnostics10100779] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 02/06/2023] Open
Abstract
Inherited retinal diseases (IRDs), which are among the most common genetic diseases in humans, define a clinically and genetically heterogeneous group of disorders. Over 80 forms of syndromic IRDs have been described. Approximately 200 genes are associated with these syndromes. The majority of syndromic IRDs are recessively inherited and rare. Many, although not all, syndromic IRDs can be classified into one of two major disease groups: inborn errors of metabolism and ciliopathies. Besides the retina, the systems and organs most commonly involved in syndromic IRDs are the central nervous system, ophthalmic extra-retinal tissues, ear, skeleton, kidney and the cardiovascular system. Due to the high degree of phenotypic variability and phenotypic overlap found in syndromic IRDs, correct diagnosis based on phenotypic features alone may be challenging and sometimes misleading. Therefore, genetic testing has become the benchmark for the diagnosis and management of patients with these conditions, as it complements the clinical findings and facilitates an accurate clinical diagnosis and treatment.
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22
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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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23
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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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24
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García-García G, Sanchez-Navarro I, Aller E, Jaijo T, Fuster-Garcia C, Rodríguez-Munoz A, Vallejo E, Tellería JJ, Vázquez S, Beltrán S, Derdak S, Zurita O, Villaverde-Montero C, Avila-Fernández A, Corton M, Blanco-Kelly F, Hakonarson H, Millán JM, Ayuso C. Exome sequencing identifies PEX6 mutations in three cases diagnosed with Retinitis Pigmentosa and hearing impairment. Mol Vis 2020; 26:216-225. [PMID: 32214787 PMCID: PMC7090270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 03/16/2020] [Indexed: 11/07/2022] Open
Abstract
Purpose The aim of the present work is the molecular diagnosis of three patients with deafness and retinal degeneration. Methods Three patients from two unrelated families were initially analyzed with custom gene panels for Usher genes, non-syndromic hearing loss, or inherited syndromic retinopathies and further investigated by means of clinical or whole exome sequencing. Results The study allowed us to detect likely pathogenic variants in PEX6, a gene typically involved in peroxisomal biogenesis disorders (PBDs). Beside deaf-blindness, both families showed additional features: Siblings from Family 1 showed enamel alteration and abnormal peroxisome. In addition, the brother had mild neurodevelopmental delay and nephrolithiasis. The case II:1 from Family 2 showed intellectual disability, enamel alteration, and dysmorphism. Conclusions We have reported three new cases with pathogenic variants in PEX6 presenting with milder forms of the Zellweger spectrum disorders (ZSD). The three cases showed distinct clinical features. Thus, expanding the phenotypic spectrum of PBDs and ascertaining exome sequencing is an effective strategy for an accurate diagnosis of clinically overlapping and genetically heterogeneous disorders such as deafness-blindness association.
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Affiliation(s)
- Gema García-García
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain,Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Iker Sanchez-Navarro
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Elena Aller
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain,Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Genetics Unit, La Fe University Hospital, Valencia, Spain
| | - Teresa Jaijo
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain,Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Genetics Unit, La Fe University Hospital, Valencia, Spain
| | - Carla Fuster-Garcia
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain
| | - Ana Rodríguez-Munoz
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain
| | - Elena Vallejo
- Department of Ophthalmology, Medina del Campo Hospital, Valladolid, Spain
| | | | - Selma Vázquez
- University Hospital of Valladolid, Valladolid, Spain
| | - Sergi Beltrán
- National Center of Genomic Analysis (CNAG-CRG) Centre for Genomic Regulation, Barcelona, Spain
| | - Sophia Derdak
- National Center of Genomic Analysis (CNAG-CRG) Centre for Genomic Regulation, Barcelona, Spain
| | - Olga Zurita
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Cristina Villaverde-Montero
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Almudena Avila-Fernández
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Marta Corton
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Fiona Blanco-Kelly
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children’s Hospital of Philadelphia, Philadelphia, PA,Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - José M. Millán
- Research group on Molecular, Cellular and Genomic Biomedicine, Health Research, Institute La Fe (IIS La Fe) and Mixed Unit for Rare diseases IIS La Fe - CIPF, Valencia, Spain,Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain
| | - Carmen Ayuso
- Centre for Biomedical Research on Rare Diseases (CIBERER), Madrid, Spain,Department of Genetics, IIS-Fundación Jiménez Díaz University Hospital (IIS-FJD, UAM), Madrid, Spain
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25
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Genetic Deciphering of Early-Onset and Severe Retinal Dystrophy Associated with Sensorineural Hearing Loss. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:233-238. [PMID: 31884617 DOI: 10.1007/978-3-030-27378-1_38] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The specific association of Leber congenital amaurosis (LCA) or early-onset severe retinal dystrophy (LCA-like) with sensorineural hearing loss (SHL) is uncommon. Recently, we ascribed some of these distinctive associations to dominant and de novo mutations in the β-tubulin 4B isotype-encoding gene (TUBB4B), providing a link between a sensorineural disease and anomalies in microtubules behavior. Here, we report 12 sporadic cases with LCA/SHL or LCA-like/SHL and no TUBB4B mutation. Trio-based whole exome sequencing (WES) identified disease-causing mutations in 5/12 cases. Four out of five carried biallelic mutations in PEX1 (1/4) or PEX6 (3/4), involved in peroxisome biogenesis disorders from Zellweger syndrome characterized by severe neurologic and neurosensory dysfunctions, craniofacial abnormalities, and liver dysfunction to Heimler syndrome associating SHL, enamel hypoplasia of the secondary dentition, nail abnormalities, and occasional retinal disease. Upon reexamination, the index case carrying PEX1 mutations, a 4-year-old girl, presented additional symptoms consistent with Zellweger syndrome. Reexamination of individuals with PEX6 mutations (1/3 unavailable) revealed normal nails but enamel hypoplasia affecting one primary teeth in a 4-year-old girl and severe enamel hypoplasia of primary teeth hidden by dental prosthesis in a 50-year-old male, describing a novel PEX6-associated disease of the Zellweger/Heimler spectrum. Finally, hemizygosity for a CACNA1F mutation was identified in an 18-year-old male addressed for LCA/SHL, redirecting the retinal diagnosis to congenital stationary night blindness (CSNB2A). Consistent with the pure CSNB2A retinal involvement, SHL was ascribed to biallelic mutations in another gene, STRC, involved in nonprogressive DFNB16 deafness.
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26
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Mechaussier S, Perrault I, Dollfus H, Bloch-Zupan A, Loundon N, Jonard L, Marlin S. Heimler Syndrome. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1299:81-87. [PMID: 33417209 DOI: 10.1007/978-3-030-60204-8_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Heimler syndrome is a rare syndrome associating sensorineural hearing loss with retinal dystrophy and amelogenesis imperfecta due to PEX1 or PEX6 biallelic pathogenic variations. This syndrome is one of the less severe forms of peroxisome biogenesis disorders. In this chapter, we will review clinical, biological, and genetic knowledges about the Heimler syndrome.
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Affiliation(s)
- S Mechaussier
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris University, Paris, France
| | - I Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR1163, Institute of Genetic Diseases, Imagine and Paris University, Paris, France
| | - H Dollfus
- Department of Medical Genetics, Institute of Medical Genetics of Alsace (IGMA), Strasbourg University Hospitals - Hautepierre Hospital, Strasbourg, France.,Laboratory of Medical Genetics, INSERM U1112, Institute of Medical Genetics of Alsace (IGMA), Strasbourg University, Strasbourg, France
| | - A Bloch-Zupan
- Strasbourg University, Faculty of Dental Medicine, Institute for Advanced Study (USIAS), Strasbourg, France.,Strasbourg University Hospitals (HUS), Oral Surgery and Oral Medecine Unit, Dental Clinic, Civil Hospital, Reference Center for Rare Oral and Dental Diseases, O-Rares, Filière Santé Maladies rares TETE COU, European Reference Network ERN CRANIO, Strasbourg, France.,Strasbourg University, Institute of Genetics and Molecular and Cellular Biology (IGBMC), Illkirch, France
| | - N Loundon
- Pediatric ENT Department, Necker-Enfants Malades Hospital, Paris, France.,Reference Center for Rare Diseases "Genetic deafness", Filière Santé Maladies rares SENSGENE, European Reference Network ERN CRANIO, Federation of Genetic, Necker-Enfants Malades Hospital, Paris, France
| | - L Jonard
- Reference Center for Rare Diseases "Genetic deafness", Filière Santé Maladies rares SENSGENE, European Reference Network ERN CRANIO, Federation of Genetic, Necker-Enfants Malades Hospital, Paris, France
| | - S Marlin
- Reference Center for Rare Diseases "Genetic deafness", Filière Santé Maladies rares SENSGENE, European Reference Network ERN CRANIO, Federation of Genetic, Necker-Enfants Malades Hospital, Paris, France. .,Laboratory of Embryology and Genetics of Malformations, INSERM UMR 1163, Institute of Genetic Diseases, Imagine and Paris University, Paris, France.
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27
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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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28
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Fu Z, Chen CT, Cagnone G, Heckel E, Sun Y, Cakir B, Tomita Y, Huang S, Li Q, Britton W, Cho SS, Kern TS, Hellström A, Joyal JS, Smith LE. Dyslipidemia in retinal metabolic disorders. EMBO Mol Med 2019; 11:e10473. [PMID: 31486227 PMCID: PMC6783651 DOI: 10.15252/emmm.201910473] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/10/2019] [Accepted: 08/15/2019] [Indexed: 12/24/2022] Open
Abstract
The light‐sensitive photoreceptors in the retina are extremely metabolically demanding and have the highest density of mitochondria of any cell in the body. Both physiological and pathological retinal vascular growth and regression are controlled by photoreceptor energy demands. It is critical to understand the energy demands of photoreceptors and fuel sources supplying them to understand neurovascular diseases. Retinas are very rich in lipids, which are continuously recycled as lipid‐rich photoreceptor outer segments are shed and reformed and dietary intake of lipids modulates retinal lipid composition. Lipids (as well as glucose) are fuel substrates for photoreceptor mitochondria. Dyslipidemia contributes to the development and progression of retinal dysfunction in many eye diseases. Here, we review photoreceptor energy demands with a focus on lipid metabolism in retinal neurovascular disorders.
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Affiliation(s)
- Zhongjie Fu
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA.,Manton Center for Orphan Disease, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Chuck T Chen
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Gael Cagnone
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Emilie Heckel
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Ye Sun
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Bertan Cakir
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Yohei Tomita
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Shuo Huang
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Qian Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - William Britton
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Steve S Cho
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
| | - Timothy S Kern
- Center for Translational Vision Research, Gavin Herbert Eye Institute, Irvine, CA, USA
| | - Ann Hellström
- Section for Ophthalmology, Department of Clinical Neuroscience, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden
| | - Jean-Sébastien Joyal
- Department of Pediatrics, Pharmacology and Ophthalmology, CHU Sainte-Justine Research Center, Université de Montréal, Montreal, QC, Canada.,Department of Pharmacology and Therapeutics, University of Montreal, Montreal, QC, Canada
| | - Lois Eh Smith
- Department of Ophthalmology, Harvard Medical School, Boston Children's Hospital, Boston, MA, USA
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29
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Schieferdecker A, Wendler P. Structural Mapping of Missense Mutations in the Pex1/Pex6 Complex. Int J Mol Sci 2019; 20:ijms20153756. [PMID: 31374812 PMCID: PMC6696164 DOI: 10.3390/ijms20153756] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 01/05/2023] Open
Abstract
Peroxisome biogenesis disorders (PBDs) are nontreatable hereditary diseases with a broad range of severity. Approximately 65% of patients are affected by mutations in the peroxins Pex1 and Pex6. The proteins form the heteromeric Pex1/Pex6 complex, which is important for protein import into peroxisomes. To date, no structural data are available for this AAA+ ATPase complex. However, a wealth of information can be transferred from low-resolution structures of the yeast scPex1/scPex6 complex and homologous, well-characterized AAA+ ATPases. We review the abundant records of missense mutations described in PBD patients with the aim to classify and rationalize them by mapping them onto a homology model of the human Pex1/Pex6 complex. Several mutations concern functionally conserved residues that are implied in ATP hydrolysis and substrate processing. Contrary to fold destabilizing mutations, patients suffering from function-impairing mutations may not benefit from stabilizing agents, which have been reported as potential therapeutics for PBD patients.
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Affiliation(s)
- Anne Schieferdecker
- Institute of Biochemistry and Biology, University of Potsdam, D-14476 Potsdam, Germany
| | - Petra Wendler
- Institute of Biochemistry and Biology, University of Potsdam, D-14476 Potsdam, Germany.
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30
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Yu HL, Shen Y, Sun YM, Zhang Y. Two novel mutations of PEX6 in one Chinese Zellweger spectrum disorder and their clinical characteristics. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:368. [PMID: 31555682 DOI: 10.21037/atm.2019.06.42] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Zellweger spectrum disorder (ZSD) is an autosomal recessive peroxisome biogenesis disorder (PBD) caused by bi-allelic mutations in any of the 13 PEX family genes. Methods We reported a Chinese PBD-ZSD patient with compound heterozygous mutations of PEX6 detected by target sequencing and Sanger sequencing. The clinical materials were collected. In silico analysis were used to evaluate the pathogenicity of the two mutations. An updated review summarized the genotype-phenotype correlation of PBD patients with PEX6 mutations. Results The patient was diagnosed as PBD-ZSD and displayed retinitis pigmentosa, bilateral sensorineural hearing loss, hypotonia, developmental delay, ovarian and enamel dysplasia. Elevated very long chain fatty acids were shown and a pattern of leukodystrophy was displayed through MRI. The two mutations were novel with p.Cys358* and p.Leu83Pro, both classified as pathogenic according to American College of Medical Genetics and Genomics guideline. Phenotype-genotype correlations were shown in the reported patients with PBD-ZSD continuum. Conclusions we reported the first Chinese PBD-ZSD patient with 2 novel mutations in PEX6. Target sequencing and VLFAC were helpful in diagnosis.
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Affiliation(s)
- Hui-Ling Yu
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yan Shen
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yi-Min Sun
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yue Zhang
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
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31
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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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Genetic and Clinical Findings in a Large Cohort of Chinese Patients with Suspected Retinitis Pigmentosa. Ophthalmology 2019; 126:1549-1556. [PMID: 31054281 DOI: 10.1016/j.ophtha.2019.04.038] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 12/21/2022] Open
Abstract
PURPOSE To characterize the genetic landscape of patients with suspected retinitis pigmentosa (RP) in the Chinese population. DESIGN Cohort study. PARTICIPANTS A total of 1243 patients of Chinese origin with clinically suspected RP and their available family members (n = 2701) were recruited. METHODS All patients and available family members were screened using multigene panel testing (including 586 eye disease-associated genes), followed by clinical variant interpretation. MAIN OUTCOME MEASURES Diagnostic yield, the 17 most commonly implicated genes, age at onset, de novo mutations, and clinical usefulness of genetic testing. RESULTS Overall, 72.08% of patients received a molecular diagnosis, and the 17 top genes covered 75.63% of diagnostic cases. Diagnostic yield was higher among patients in the early-onset subgroup (≤5 years old, 79.58%) than in the childhood or adolescence-onset subgroup (6-16 years old, 73.74%) and late-onset subgroup (≥17 years old, 65.99%). Moreover, different genes associated with different onset ages and subgroups with different onset ages showed a diverse mutation spectrum. Only 11 de novo mutations (3.18%) were identified. Furthermore, 16.84% of the patients who received a molecular diagnosis had refinement of the initial clinical diagnoses, and the remaining 83.16% received definite genetic subtypes of RP. CONCLUSIONS This large cohort study provides population-based data of the genome landscape of patients with suspected RP in China. The diagnostic yield was significantly higher than that in previous studies, and the mutation spectrum is completely different with other populations. Genetic testing improves the chance to establish a precise diagnosis, identifies features not previously determined, and allows a more accurate refinement of risk to family members. Our results not only expand the existing genotypic spectrum but also serve as an efficient reference for the design of panel-based genetic diagnostic testing and genetic counseling for patients with suspected RP in China.
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Both rare and common genetic variants contribute to autism in the Faroe Islands. NPJ Genom Med 2019; 4:1. [PMID: 30675382 PMCID: PMC6341098 DOI: 10.1038/s41525-018-0075-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 12/13/2018] [Indexed: 11/09/2022] Open
Abstract
The number of genes associated with autism is increasing, but few studies have been performed on epidemiological cohorts and in isolated populations. Here, we investigated 357 individuals from the Faroe Islands including 36 individuals with autism, 136 of their relatives and 185 non-autism controls. Data from SNP array and whole exome sequencing revealed that individuals with autism had a higher burden of rare exonic copy-number variants altering autism associated genes (deletions (p = 0.0352) or duplications (p = 0.0352)), higher inbreeding status (p = 0.023) and a higher load of rare homozygous deleterious variants (p = 0.011) compared to controls. Our analysis supports the role of several genes/loci associated with autism (e.g., NRXN1, ADNP, 22q11 deletion) and identified new truncating (e.g., GRIK2, ROBO1, NINL, and IMMP2L) or recessive deleterious variants (e.g., KIRREL3 and CNTNAP2) affecting autism-associated genes. It also revealed three genes involved in synaptic plasticity, RIMS4, KALRN, and PLA2G4A, carrying de novo deleterious variants in individuals with autism without intellectual disability. In summary, our analysis provides a better understanding of the genetic architecture of autism in isolated populations by highlighting the role of both common and rare gene variants and pointing at new autism-risk genes. It also indicates that more knowledge about how multiple genetic hits affect neuronal function will be necessary to fully understand the genetic architecture of autism.
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Das Y, Roose N, De Groef L, Fransen M, Moons L, Van Veldhoven PP, Baes M. Differential distribution of peroxisomal proteins points to specific roles of peroxisomes in the murine retina. Mol Cell Biochem 2019; 456:53-62. [PMID: 30604065 DOI: 10.1007/s11010-018-3489-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 12/14/2018] [Indexed: 12/21/2022]
Abstract
The retinal pathology in peroxisomal disorders suggests that peroxisomes are important to maintain retinal homeostasis and function. These ubiquitous cell organelles are mainly involved in lipid metabolism, which comprises α- and β-oxidation and ether lipid synthesis. Although peroxisomes were extensively studied in liver, their role in the retina still remains to be elucidated. As a first step in gaining more insight into the role of peroxisomes in retinal physiology, we performed immunohistochemical stainings, immunoblotting and enzyme activity measurements to reveal the distribution of peroxisomes and peroxisomal lipid metabolizing enzymes in the murine retina. Whereas peroxisomes were detected in every retinal layer, we found a clear differential distribution of the peroxisomal lipid metabolizing enzymes in the neural retina compared to the retinal pigment epithelium. In particular, the ABC transporters that transfer lipid substrates into the organelle as well as several enzymes of the β-oxidation pathway were enriched either in the neural retina or in the retinal pigment epithelium. In conclusion, our results strongly indicate that peroxisome function varies between different regions in the murine retina.
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Affiliation(s)
- Yannick Das
- Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Nele Roose
- Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Lies De Groef
- Department of Biology, Animal Physiology and Neurobiology, KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Marc Fransen
- Department of Cellular and Molecular Medicine, Lipid Biochemistry and Protein Interactions (LIPIT), KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Lieve Moons
- Department of Biology, Animal Physiology and Neurobiology, KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Paul P Van Veldhoven
- Department of Cellular and Molecular Medicine, Lipid Biochemistry and Protein Interactions (LIPIT), KU Leuven -University of Leuven, 3000, Leuven, Belgium
| | - Myriam Baes
- Department of Pharmaceutical and Pharmacological Sciences, Cell Metabolism, KU Leuven -University of Leuven, 3000, Leuven, Belgium.
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35
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Das Y, Baes M. Peroxisomal Disorders and Retinal Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1185:317-321. [PMID: 31884631 DOI: 10.1007/978-3-030-27378-1_52] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Peroxisomal disorders are a group of inherited metabolic diseases, which can be incompatible with life in the postnatal period or allow survival into adulthood. Retinopathy is a recurrent feature in both the severely and mildly affected patients, which can be accompanied with other ophthalmological pathologies. Thanks to next-generation sequencing, patients originally identified with other inherited blinding diseases were reclassified as suffering from peroxisomal disorders. In addition, new peroxisomal gene defects or disease presentations exhibiting retinal degeneration were recently identified. The pathogenic mechanisms underlying retinopathy in peroxisomal disorders remain unresolved.
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Affiliation(s)
- Yannick Das
- KU Leuven - University of Leuven, Department for Pharmaceutical and Pharmacological Sciences, Lab for Cell Metabolism, Leuven, Belgium
| | - Myriam Baes
- KU Leuven - University of Leuven, Department for Pharmaceutical and Pharmacological Sciences, Lab for Cell Metabolism, Leuven, Belgium.
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Guder P, Lotz-Havla AS, Woidy M, Reiß DD, Danecka MK, Schatz UA, Becker M, Ensenauer R, Pagel P, Büttner L, Muntau AC, Gersting SW. Isoform-specific domain organization determines conformation and function of the peroxisomal biogenesis factor PEX26. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:518-531. [PMID: 30366024 DOI: 10.1016/j.bbamcr.2018.10.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 10/11/2018] [Accepted: 10/18/2018] [Indexed: 10/28/2022]
Abstract
Peroxisomal biogenesis factor PEX26 is a membrane anchor for the multi-subunit PEX1-PEX6 protein complex that controls ubiquitination and dislocation of PEX5 cargo receptors for peroxisomal matrix protein import. PEX26 associates with the peroxisomal translocation pore via PEX14 and a splice variant (PEX26Δex5) of unknown function has been reported. Here, we demonstrate PEX26 homooligomerization mediated by two heptad repeat domains adjacent to the transmembrane domain. We show that isoform-specific domain organization determines PEX26 oligomerization and impacts peroxisomal β-oxidation and proliferation. PEX26 and PEX26Δex5 displayed different patterns of interaction with PEX2-PEX10 or PEX13-PEX14 complexes, which relate to distinct pre-peroxisomes in the de novo synthesis pathway. Our data support an alternative PEX14-dependent mechanism of peroxisomal membrane association for the splice variant, which lacks a transmembrane domain. Structure-function relationships of PEX26 isoforms explain an extended function in peroxisomal homeostasis and these findings may improve our understanding of the broad phenotype of PEX26-associated human disorders.
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Affiliation(s)
- Philipp Guder
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Amelie S Lotz-Havla
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany
| | - Mathias Woidy
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Dunja D Reiß
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany
| | - Marta K Danecka
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ulrich A Schatz
- Department for Medical Genetics, Molecular and Clinical Pharmacology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Marc Becker
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany; Labor Becker Olgemöller und Kollegen, 81671 Munich, Germany
| | - Regina Ensenauer
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany; Experimental Pediatrics, Department of General Pediatrics, Neonatology and Pediatric Cardiology, University Children's Hospital, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany
| | - Philipp Pagel
- Lehrstuhl für Genomorientierte Bioinformatik, Technische Universität, 85350 Freising, Germany; numares GmbH, Josef-Engert-Str. 9, 93053 Regensburg, Germany
| | - Lars Büttner
- Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, 80337 Munich, Germany
| | - Ania C Muntau
- Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Søren W Gersting
- University Children's Research@Kinder-UKE, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; Children's Hospital, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany.
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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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A pex1 missense mutation improves peroxisome function in a subset of Arabidopsis pex6 mutants without restoring PEX5 recycling. Proc Natl Acad Sci U S A 2018; 115:E3163-E3172. [PMID: 29555730 DOI: 10.1073/pnas.1721279115] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Peroxisomes are eukaryotic organelles critical for plant and human development because they house essential metabolic functions, such as fatty acid β-oxidation. The interacting ATPases PEX1 and PEX6 contribute to peroxisome function by recycling PEX5, a cytosolic receptor needed to import proteins targeted to the peroxisomal matrix. Arabidopsis pex6 mutants exhibit low PEX5 levels and defects in peroxisomal matrix protein import, oil body utilization, peroxisomal metabolism, and seedling growth. These defects are hypothesized to stem from impaired PEX5 retrotranslocation leading to PEX5 polyubiquitination and consequent degradation of PEX5 via the proteasome or of the entire organelle via autophagy. We recovered a pex1 missense mutation in a screen for second-site suppressors that restore growth to the pex6-1 mutant. Surprisingly, this pex1-1 mutation ameliorated the metabolic and physiological defects of pex6-1 without restoring PEX5 levels. Similarly, preventing autophagy by introducing an atg7-null allele partially rescued pex6-1 physiological defects without restoring PEX5 levels. atg7 synergistically improved matrix protein import in pex1-1 pex6-1, implying that pex1-1 improves peroxisome function in pex6-1 without impeding autophagy of peroxisomes (i.e., pexophagy). pex1-1 differentially improved peroxisome function in various pex6 alleles but worsened the physiological and molecular defects of a pex26 mutant, which is defective in the tether anchoring the PEX1-PEX6 hexamer to the peroxisome. Our results support the hypothesis that, beyond PEX5 recycling, PEX1 and PEX6 have additional functions in peroxisome homeostasis and perhaps in oil body utilization.
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39
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Cho DH, Kim YS, Jo DS, Choe SK, Jo EK. Pexophagy: Molecular Mechanisms and Implications for Health and Diseases. Mol Cells 2018; 41:55-64. [PMID: 29370694 PMCID: PMC5792714 DOI: 10.14348/molcells.2018.2245] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 12/28/2017] [Accepted: 12/29/2017] [Indexed: 02/06/2023] Open
Abstract
Autophagy is an intracellular degradation pathway for large protein aggregates and damaged organelles. Recent studies have indicated that autophagy targets cargoes through a selective degradation pathway called selective autophagy. Peroxisomes are dynamic organelles that are crucial for health and development. Pexophagy is selective autophagy that targets peroxisomes and is essential for the maintenance of homeostasis of peroxisomes, which is necessary in the prevention of various peroxisome-related disorders. However, the mechanisms by which pexophagy is regulated and the key players that induce and modulate pexophagy are largely unknown. In this review, we focus on our current understanding of how pexophagy is induced and regulated, and the selective adaptors involved in mediating pexophagy. Furthermore, we discuss current findings on the roles of pexophagy in physiological and pathological responses, which provide insight into the clinical relevance of pexophagy regulation. Understanding how pexophagy interacts with various biological functions will provide fundamental insights into the function of pexophagy and facilitate the development of novel therapeutics against peroxisomal dysfunction-related diseases.
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Affiliation(s)
- Dong-Hyung Cho
- Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104,
Korea
| | - Yi Sak Kim
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon 35015,
Korea
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon 35015,
Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon 35015,
Korea
| | - Doo Sin Jo
- Graduate School of East-West Medical Science, Kyung Hee University, Yongin 17104,
Korea
| | - Seong-Kyu Choe
- Department of Microbiology and Center for Metabolic Function Regulation, Wonkwang University School of Medicine, Iksan 54538,
Korea
| | - Eun-Kyeong Jo
- Department of Microbiology, Chungnam National University School of Medicine, Daejeon 35015,
Korea
- Department of Medical Science, Chungnam National University School of Medicine, Daejeon 35015,
Korea
- Infection Control Convergence Research Center, Chungnam National University School of Medicine, Daejeon 35015,
Korea
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40
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Rinaldi MA, Fleming WA, Gonzalez KL, Park J, Ventura MJ, Patel AB, Bartel B. The PEX1 ATPase Stabilizes PEX6 and Plays Essential Roles in Peroxisome Biology. PLANT PHYSIOLOGY 2017; 174:2231-2247. [PMID: 28600347 PMCID: PMC5543962 DOI: 10.1104/pp.17.00548] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/07/2017] [Indexed: 05/29/2023]
Abstract
A variety of metabolic pathways are sequestered in peroxisomes, conserved organelles that are essential for human and plant survival. Peroxin (PEX) proteins generate and maintain peroxisomes. The PEX1 ATPase facilitates recycling of the peroxisome matrix protein receptor PEX5 and is the most commonly affected peroxin in human peroxisome biogenesis disorders. Here, we describe the isolation and characterization of, to our knowledge, the first Arabidopsis (Arabidopsis thaliana) pex1 missense alleles: pex1-2 and pex1-3pex1-2 displayed peroxisome-related defects accompanied by reduced PEX1 and PEX6 levels. These pex1-2 defects were exacerbated by growth at high temperature and ameliorated by growth at low temperature or by PEX6 overexpression, suggesting that PEX1 enhances PEX6 stability and vice versa. pex1-3 conferred embryo lethality when homozygous, confirming that PEX1, like several other Arabidopsis peroxins, is essential for embryogenesis. pex1-3 displayed symptoms of peroxisome dysfunction when heterozygous; this semidominance is consistent with PEX1 forming a heterooligomer with PEX6 that is poisoned by pex1-3 subunits. Blocking autophagy partially rescued PEX1/pex1-3 defects, including the restoration of normal peroxisome size, suggesting that increasing peroxisome abundance can compensate for the deficiencies caused by pex1-3 and that the enlarged peroxisomes visible in PEX1/pex1-3 may represent autophagy intermediates. Overexpressing PEX1 in wild-type plants impaired growth, suggesting that excessive PEX1 can be detrimental. Our genetic, molecular, and physiological data support the heterohexamer model of PEX1-PEX6 function in plants.
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Affiliation(s)
- Mauro A Rinaldi
- Department of BioSciences, Rice University, Houston, Texas 77005
| | | | - Kim L Gonzalez
- Department of BioSciences, Rice University, Houston, Texas 77005
| | - Jaeseok Park
- Department of BioSciences, Rice University, Houston, Texas 77005
| | | | - Ashish B Patel
- Department of BioSciences, Rice University, Houston, Texas 77005
| | - Bonnie Bartel
- Department of BioSciences, Rice University, Houston, Texas 77005
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41
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Neuhaus C, Eisenberger T, Decker C, Nagl S, Blank C, Pfister M, Kennerknecht I, Müller-Hofstede C, Charbel Issa P, Heller R, Beck B, Rüther K, Mitter D, Rohrschneider K, Steinhauer U, Korbmacher HM, Huhle D, Elsayed SM, Taha HM, Baig SM, Stöhr H, Preising M, Markus S, Moeller F, Lorenz B, Nagel-Wolfrum K, Khan AO, Bolz HJ. Next-generation sequencing reveals the mutational landscape of clinically diagnosed Usher syndrome: copy number variations, phenocopies, a predominant target for translational read-through, and PEX26 mutated in Heimler syndrome. Mol Genet Genomic Med 2017; 5:531-552. [PMID: 28944237 PMCID: PMC5606877 DOI: 10.1002/mgg3.312] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/06/2017] [Accepted: 06/09/2017] [Indexed: 12/23/2022] Open
Abstract
Background Combined retinal degeneration and sensorineural hearing impairment is mostly due to autosomal recessive Usher syndrome (USH1: congenital deafness, early retinitis pigmentosa (RP); USH2: progressive hearing impairment, RP). Methods Sanger sequencing and NGS of 112 genes (Usher syndrome, nonsyndromic deafness, overlapping conditions), MLPA, and array‐CGH were conducted in 138 patients clinically diagnosed with Usher syndrome. Results A molecular diagnosis was achieved in 97% of both USH1 and USH2 patients, with biallelic mutations in 97% (USH1) and 90% (USH2), respectively. Quantitative readout reliably detected CNVs (confirmed by MLPA or array‐CGH), qualifying targeted NGS as one tool for detecting point mutations and CNVs. CNVs accounted for 10% of identified USH2A alleles, often in trans to seemingly monoallelic point mutations. We demonstrate PTC124‐induced read‐through of the common p.Trp3955* nonsense mutation (13% of detected USH2A alleles), a potential therapy target. Usher gene mutations were found in most patients with atypical Usher syndrome, but the diagnosis was adjusted in case of double homozygosity for mutations in OTOA and NR2E3, genes implicated in isolated deafness and RP. Two patients with additional enamel dysplasia had biallelic PEX26 mutations, for the first time linking this gene to Heimler syndrome. Conclusion Targeted NGS not restricted to Usher genes proved beneficial in uncovering conditions mimicking Usher syndrome.
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Affiliation(s)
| | | | | | - Sandra Nagl
- Bioscientia Center for Human GeneticsIngelheimGermany
| | | | - Markus Pfister
- HNO-Praxis SarnenSarnenSwitzerland.,Molecular Genetics, THRCDepartment of OtolaryngologyUniversity of TübingenTübingenGermany
| | - Ingo Kennerknecht
- Institute of Human GeneticsWestfälische Wilhelms-UniversitätMünsterGermany
| | | | - Peter Charbel Issa
- Department of OphthalmologyUniversity of BonnBonnGermany.,Center for Rare Diseases Bonn (ZSEB)University of BonnBonnGermany.,Oxford Eye HospitalUniversity of OxfordOxfordUK
| | - Raoul Heller
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | - Bodo Beck
- Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
| | | | - Diana Mitter
- Institute of Human GeneticsUniversity of Leipzig Hospitals and ClinicsLeipzigGermany
| | | | | | - Heike M Korbmacher
- Department of OrthodonticsGiessen and Marburg University Hospital, Marburg CampusMarburgGermany
| | | | - Solaf M Elsayed
- Medical Genetics CenterCairoEgypt.,Children's HospitalAin Shams UniversityCairoEgypt
| | | | - Shahid M Baig
- Human Molecular Genetics LaboratoryHealth Biotechnology DivisionNational Institute for Biotechnology and Genetic Engineering (NIBGE)FaisalabadPakistan
| | - Heidi Stöhr
- Department of Human GeneticsUniversity Medical Center RegensburgRegensburgGermany
| | - Markus Preising
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | | | - Fabian Moeller
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Birgit Lorenz
- Department of OphthalmologyJustus-Liebig-University GiessenGiessenGermany
| | - Kerstin Nagel-Wolfrum
- Department of Cell and Matrix BiologyInstitute of Zoology, Johannes GutenbergUniversity of MainzMainzGermany
| | - Arif O Khan
- Division of Pediatric OphthalmologyKing Khaled Eye Specialist HospitalRiyadhSaudi Arabia.,Eye InstituteCleveland ClinicAbu DhabiUAE
| | - Hanno J Bolz
- Bioscientia Center for Human GeneticsIngelheimGermany.,Institute of Human GeneticsUniversity Hospital of CologneCologneGermany
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