1
|
Azuelos C, Marquis MA, Laberge AM. A systematic review of the assessment of the clinical utility of genomic sequencing: Implications of the lack of standard definitions and measures of clinical utility. Eur J Med Genet 2024; 68:104925. [PMID: 38432472 DOI: 10.1016/j.ejmg.2024.104925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/31/2023] [Accepted: 02/11/2024] [Indexed: 03/05/2024]
Abstract
PURPOSE Exome sequencing (ES) and genome sequencing (GS) are diagnostic tests for rare genetic diseases. Studies report clinical utility of ES/GS. The goal of this systematic review is to establish how clinical utility is defined and measured in studies evaluating the impacts of ES/GS results for pediatric patients. METHODS Relevant articles were identified in PubMed, Medline, Embase, and Web of Science. Eligible studies assessed clinical utility of ES/GS for pediatric patients published before 2021. Other relevant articles were added based on articles' references. Articles were coded to assess definitions and measures of clinical utility. RESULTS Of 1346 articles, 83 articles met eligibility criteria. Clinical utility was not clearly defined in 19% of studies and 92% did not use an explicit measure of clinical utility. When present, definitions of clinical utility diverged from recommended definitions and varied greatly, from narrow (diagnostic yield of ES/GS) to broad (including decisions about withdrawal of care/palliative care and/or impacts on other family members). CONCLUSION Clinical utility is used to guide policy and practice decisions about test use. The lack of a standard definition of clinical utility of ES/GS may lead to under- or overestimations of clinical utility, complicating policymaking and raising ethical issues.
Collapse
Affiliation(s)
- Claudia Azuelos
- Medical Genetics, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada.
| | - Marc-Antoine Marquis
- Palliative Care, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada
| | - Anne-Marie Laberge
- Medical Genetics, Dept of Pediatrics, CHU Sainte-Justine and Université de Montréal, Canada.
| |
Collapse
|
2
|
Nagree MS, Rybova J, Kleynerman A, Ahrenhoerster CJ, Saville JT, Xu T, Bachochin M, McKillop WM, Lawlor MW, Pshezhetsky AV, Isaeva O, Budde MD, Fuller M, Medin JA. Spinal muscular atrophy-like phenotype in a mouse model of acid ceramidase deficiency. Commun Biol 2023; 6:560. [PMID: 37231125 DOI: 10.1038/s42003-023-04932-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 05/12/2023] [Indexed: 05/27/2023] Open
Abstract
Mutations in ASAH1 have been linked to two allegedly distinct disorders: Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). We have previously reported FD-like phenotypes in mice harboring a single amino acid substitution in acid ceramidase (ACDase), P361R, known to be pathogenic in humans (P361R-Farber). Here we describe a mouse model with an SMA-PME-like phenotype (P361R-SMA). P361R-SMA mice live 2-3-times longer than P361R-Farber mice and have different phenotypes including progressive ataxia and bladder dysfunction, which suggests neurological dysfunction. We found profound demyelination, loss of axons, and altered sphingolipid levels in P361R-SMA spinal cords; severe pathology was restricted to the white matter. Our model can serve as a tool to study the pathological effects of ACDase deficiency on the central nervous system and to evaluate potential therapies for SMA-PME.
Collapse
Affiliation(s)
- Murtaza S Nagree
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, ON, Canada
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Jitka Rybova
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Annie Kleynerman
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | | | - Jennifer T Saville
- Genetics and Molecular Pathology, SA Pathology at Women's and Children's Hospital, and Adelaide Medical School, University of Adelaide, Adelaide, SA, 5006, Australia
| | - TianMeng Xu
- CHU Sainte-Justine, Université de Montréal, Montréal, QC, H3T 1C5, Canada
| | | | - William M McKillop
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Michael W Lawlor
- Department of Pathology and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | | | - Olena Isaeva
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Matthew D Budde
- Clement J. Zablocki Veteran's Affairs Medical Center, Milwaukee, WI, 53295, USA
- Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Maria Fuller
- Genetics and Molecular Pathology, SA Pathology at Women's and Children's Hospital, and Adelaide Medical School, University of Adelaide, Adelaide, SA, 5006, Australia
- Adelaide Medical School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Jeffrey A Medin
- Department of Medical Biophysics, University of Toronto, Toronto, M5G 1L7, ON, Canada.
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI, 53226, USA.
| |
Collapse
|
3
|
Kleynerman A, Rybova J, Faber ML, McKillop WM, Levade T, Medin JA. Acid Ceramidase Deficiency: Bridging Gaps between Clinical Presentation, Mouse Models, and Future Therapeutic Interventions. Biomolecules 2023; 13:biom13020274. [PMID: 36830643 PMCID: PMC9953133 DOI: 10.3390/biom13020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) are ultra-rare, autosomal-recessive, acid ceramidase (ACDase) deficiency disorders caused by ASAH1 gene mutations. Currently, 73 different mutations in the ASAH1 gene have been described in humans. These mutations lead to reduced ACDase activity and ceramide (Cer) accumulation in many tissues. Presenting as divergent clinical phenotypes, the symptoms of FD vary depending on central nervous system (CNS) involvement and severity. Classic signs of FD include, but are not limited to, a hoarse voice, distended joints, and lipogranulomas found subcutaneously and in other tissues. Patients with SMA-PME lack the most prominent clinical signs seen in FD. Instead, they demonstrate muscle weakness, tremors, and myoclonic epilepsy. Several ACDase-deficient mouse models have been developed to help elucidate the complex consequences of Cer accumulation. In this review, we compare clinical reports on FD patients and experimental descriptions of ACDase-deficient mouse models. We also discuss clinical presentations, potential therapeutic strategies, and future directions for the study of FD and SMA-PME.
Collapse
Affiliation(s)
- Annie Kleynerman
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jitka Rybova
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Mary L. Faber
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - William M. McKillop
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Thierry Levade
- Laboratoire de Biochimie Métabolique, CHU Toulouse, and INSERM U1037, Centre de Recherches en Cancérologie de Toulouse, Université Paul Sabatier, 31062 Toulouse, France
| | - Jeffrey A. Medin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Correspondence: ; Tel.: +1-414-955-4118
| |
Collapse
|
4
|
Lee MM, McDowell GSV, De Vivo DC, Friedman D, Berkovic SF, Spanou M, Dinopoulos A, Grand K, Sanchez‐Lara PA, Allen‐Sharpley M, Warman‐Chardon J, Solyom A, Levade T, Schuchman EH, Bennett SAL, Dyment DA, Pearson TS. The clinical spectrum of SMA-PME and in vitro normalization of its cellular ceramide profile. Ann Clin Transl Neurol 2022; 9:1941-1952. [PMID: 36325744 PMCID: PMC9735369 DOI: 10.1002/acn3.51687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/12/2022] [Accepted: 10/14/2022] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE The objectives of this study were to define the clinical and biochemical spectrum of spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) and to determine if aberrant cellular ceramide accumulation could be normalized by enzyme replacement. METHODS Clinical features of 6 patients with SMA-PME were assessed by retrospective chart review, and a literature review of 24 previously published cases was performed. Leukocyte enzyme activity of acid ceramidase was assessed with a fluorescence-based assay. Skin fibroblast ceramide content and was assessed by high performance liquid chromatography, electrospray ionization tandem mass spectroscopy. Enzyme replacement was assessed using recombinant human acid ceramidase (rhAC) in vitro. RESULTS The six new patients showed the hallmark features of SMA-PME, with variable initial symptom and age of onset. Five of six patients carried at least one of the recurrent SMA-PME variants observed in two specific codons of ASAH1. A review of 30 total cases revealed that patients who were homozygous for the most common c.125C > T variant presented in the first decade of life with limb-girdle weakness as the initial symptom. Sensorineural hearing loss was associated with the c.456A > C variant. Leukocyte acid ceramidase activity varied from 4.1%-13.1% of controls. Ceramide species in fibroblasts were detected and total cellular ceramide content was elevated by 2 to 9-fold compared to controls. Treatment with rhAC normalized ceramide profiles in cultured fibroblasts to control levels within 48 h. INTERPRETATION This study details the genotype-phenotype correlations observed in SMA-PME and shows the impact of rhAC to correct the abnormal cellular ceramide profile in cells.
Collapse
Affiliation(s)
- Michelle M. Lee
- Department of NeurologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Graeme S. V. McDowell
- Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and ImmunologyUniversity of OttawaOttawaOntarioCanada
| | - Darryl C. De Vivo
- Departments of Neurology and PediatricsColumbia University Irving Medical CenterNew YorkNew YorkUSA
| | - Daniel Friedman
- Department of NeurologyNYU Grossman School of MedicineNew YorkNew YorkUSA
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of MedicineUniversity of MelbourneHeidelbergVictoriaAustralia
| | - Maria Spanou
- Pediatric Neurology Division, 3rd Department of PediatricsAttikon University HospitalAthensGreece
| | - Argirios Dinopoulos
- Pediatric Neurology Division, 3rd Department of PediatricsAttikon University HospitalAthensGreece
| | - Katheryn Grand
- Department of PediatricsCedars‐Sinai Medical CenterLos AngelesCaliforniaUSA
| | | | | | - Jodi Warman‐Chardon
- Department of Medicine (Neurology)Ottawa Hospital Research InstituteOttawaOntarioCanada,Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
| | | | - Thierry Levade
- Laboratoire de Biochimie MétaboliqueCHU Toulouse, INSERM U1037, Centre de Recherches en Cancérologie de Toulouse, Université Paul Sabatier ToulouseToulouseFrance
| | - Edward H. Schuchman
- Department of Genetics and Genomic SciencesIcahn School of Medicine at Mount SinaiNew YorkNYUSA
| | - Steffany A. L. Bennett
- Neural Regeneration Laboratory, Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and ImmunologyUniversity of OttawaOttawaOntarioCanada
| | - David A. Dyment
- Children's Hospital of Eastern Ontario Research InstituteOttawaOntarioCanada
| | - Toni S. Pearson
- Department of NeurologyWashington University School of MedicineSt. LouisMissouriUSA,Departments of Neurology and PediatricsColumbia University Irving Medical CenterNew YorkNew YorkUSA
| |
Collapse
|
5
|
Metabolic Dysfunction in Spinal Muscular Atrophy. Int J Mol Sci 2021; 22:ijms22115913. [PMID: 34072857 PMCID: PMC8198411 DOI: 10.3390/ijms22115913] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/25/2021] [Accepted: 05/29/2021] [Indexed: 12/11/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder leading to paralysis, muscle atrophy, and death. Significant advances in antisense oligonucleotide treatment and gene therapy have made it possible for SMA patients to benefit from improvements in many aspects of the once devastating natural history of the disease. How the depletion of survival motor neuron (SMN) protein, the product of the gene implicated in the disease, leads to the consequent pathogenic changes remains unresolved. Over the past few years, evidence toward a potential contribution of gastrointestinal, metabolic, and endocrine defects to disease phenotype has surfaced. These findings ranged from disrupted body composition, gastrointestinal tract, fatty acid, glucose, amino acid, and hormonal regulation. Together, these changes could have a meaningful clinical impact on disease traits. However, it is currently unclear whether these findings are secondary to widespread denervation or unique to the SMA phenotype. This review provides an in-depth account of metabolism-related research available to date, with a discussion of unique features compared to other motor neuron and related disorders.
Collapse
|
6
|
Elsea SH, Solyom A, Martin K, Harmatz P, Mitchell J, Lampe C, Grant C, Selim L, Mungan NO, Guelbert N, Magnusson B, Sundberg E, Puri R, Kapoor S, Arslan N, DiRocco M, Zaki M, Ozen S, Mahmoud IG, Ehlert K, Hahn A, Gokcay G, Torcoletti M, Ferreira CR. ASAH1 pathogenic variants associated with acid ceramidase deficiency: Farber disease and spinal muscular atrophy with progressive myoclonic epilepsy. Hum Mutat 2020; 41:1469-1487. [PMID: 32449975 DOI: 10.1002/humu.24056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/28/2020] [Accepted: 05/16/2020] [Indexed: 11/12/2022]
Abstract
Farber disease and spinal muscular atrophy with progressive myoclonic epilepsy are a spectrum of rare lysosomal storage disorders characterized by acid ceramidase deficiency (ACD), resulting from pathogenic variants in N-acylsphingosine amidohydrolase 1 (ASAH1). Other than simple listings provided in literature reviews, a curated, comprehensive list of ASAH1 mutations associated with ACD clinical phenotypes has not yet been published. This publication includes mutations in ASAH1 collected through the Observational and Cross-Sectional Cohort Study of the Natural History and Phenotypic Spectrum of Farber Disease (NHS), ClinicalTrials.gov identifier NCT03233841, in combination with an up-to-date curated list of published mutations. The NHS is the first to collect retrospective and prospective data on living and deceased patients with ACD presenting as Farber disease, who had or had not undergone hematopoietic stem cell transplantation. Forty-five patients representing the known clinical spectrum of Farber disease (living patients aged 1-28 years) were enrolled. The curation of known ASAH1 pathogenic variants using a single reference transcript includes 10 previously unpublished from the NHS and 63 that were previously reported. The publication of ASAH1 variants will be greatly beneficial to patients undergoing genetic testing in the future by providing a significantly expanded reference list of disease-causing variants.
Collapse
Affiliation(s)
- Sarah H Elsea
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | | | - Kirt Martin
- Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
| | - Paul Harmatz
- Pediatric Gastroenterolgy and Nutrition, UCSF Benioff Children's Hospital Oakland, Oakland, California
| | | | | | | | - Laila Selim
- Cairo University Children's Hospital, Cairo, Egypt
| | | | | | - Bo Magnusson
- Karolinska University Hospital, Stockholm, Sweden
| | | | - Ratna Puri
- Sir Ganga Ram Hospital, New Delhi, India
| | - Seema Kapoor
- Lok Nayak Hospital and Maulana Azad Medical College, New Delhi, India
| | - Nur Arslan
- Dokuz Eylul University Hospital, Izmir, Turkey
| | - Maja DiRocco
- Metabolic Diseases, Istituto Giannina Gaslini, Genoa, Italy
| | - Maha Zaki
- Clinical Genetics Department, National Research Center, Cairo, Egypt
| | - Seza Ozen
- Pediatric Rheumatology, Hacettepe University Hospital, Ankara, Turkey
| | | | | | - Andreas Hahn
- UKGM Universitätsklinikum Giessen, Giessen, Germany
| | | | | | - Carlos R Ferreira
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
7
|
Kyriakou K, W. Lederer C, Kleanthous M, Drousiotou A, Malekkou A. Acid Ceramidase Depletion Impairs Neuronal Survival and Induces Morphological Defects in Neurites Associated with Altered Gene Transcription and Sphingolipid Content. Int J Mol Sci 2020; 21:E1607. [PMID: 32111095 PMCID: PMC7084529 DOI: 10.3390/ijms21051607] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/22/2020] [Accepted: 02/22/2020] [Indexed: 12/11/2022] Open
Abstract
The ASAH1 gene encodes acid ceramidase (AC), an enzyme that is implicated in the metabolism of ceramide (Cer). Mutations in the ASAH1 gene cause two different disorders, Farber disease (FD), a rare lysosomal storage disorder, and a rare form of spinal muscular atrophy combined with progressive myoclonic epilepsy (SMA-PME). In the absence of human in vitro neuronal disease models and to gain mechanistic insights into pathological effects of ASAH1 deficiency, we established and characterized a stable ASAH1 knockdown (ASAH1KD) SH-SY5Y cell line. ASAH1KD cells displayed reduced proliferation due to elevated apoptosis and G1/S cell cycle arrest. Distribution of LAMP1-positive lysosomes towards the cell periphery and significantly shortened and less branched neurites upon differentiation, implicate AC for lysosome positioning and neuronal development, respectively. Lipidomic analysis revealed changes in the intracellular levels of distinct sphingolipid species, importantly without Cer accumulation, in line with altered gene transcription within the sphingolipid pathway. Additionally, the transcript levels for Rho GTPases (RhoA, Rac1, and Cdc42), which are key regulators of axonal orientation, neurite branching and lysosome positioning were found to be dysregulated. This study shows the critical role of AC in neurons and suggests how AC depletion leads to defects seen in neuropathology of SMA-PME and FD.
Collapse
Affiliation(s)
- Kalia Kyriakou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Carsten W. Lederer
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Molecular Genetics Thalassaemia Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Marina Kleanthous
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Molecular Genetics Thalassaemia Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anthi Drousiotou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| | - Anna Malekkou
- Cyprus School of Molecular Medicine, P.O. Box 23462, 1683 Nicosia, Cyprus; (K.K.); (C.W.L.); (M.K.); (A.D.)
- Biochemical Genetics Department, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
| |
Collapse
|
8
|
Shervin Badv R, Nilipour Y, Rahimi-Dehgolan S, Rashidi-Nezhad A, Ghahvechi Akbari M. A novel case report of spinal muscular atrophy with progressive myoclonic epilepsy from Iran. Int Med Case Rep J 2019; 12:155-159. [PMID: 31213928 PMCID: PMC6549484 DOI: 10.2147/imcrj.s202046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/09/2019] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a disorder characterized by decreased motor function due to the muscle atrophy in the background of degenerated anterior horn cells and motor cells of lower cranial nerves nuclei. The most frequent form is inherited as an autosomal recessive trait resulting from mutations in the survival motor neuron gene (SMN-1). On the other hand, a rare variant of this condition, named progressive myoclonic epilepsy subtype (SMA-PME) occurs in the result of a mutation in N-acylsphingosine amidohydrolase-1 gene (ASAH-1). The latter gene is responsible for lysosomal acid-ceramidase production. SMA-PME has been characterized by a progressive muscle weakness from ages 3–7 years, accompanied by epilepsy, an intractable seizure, and sometimes sensorineural hearing loss. In this report, we have presented a 15-year old female patient with SMA-PME that was attended to neurology clinic for a new onset tremor, seizure and proximal weakness in all limbs. We identified a homozygous mutation in exon II on her ASAH-1 gene [c.173C>T (p. Thr58Met)]. Also, a modest reduction was found in ceramidase-activity. As was expected patient`s seizures did not respond to conventional therapies.
Collapse
Affiliation(s)
- Reza Shervin Badv
- Children's Medical Center, Pediatrics Center of Excellence, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Yalda Nilipour
- Pediatric Pathology Research center, Research Institute for Children Health, Mofid Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahram Rahimi-Dehgolan
- Physical Medicine and Rehabilitation Department, Imam Khomeini Hospital Complex (IKHC), Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Ali Rashidi-Nezhad
- Maternal, Fetal and Neonatal Research Center, Imam khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Masood Ghahvechi Akbari
- Physical Medicine and Rehabilitation Department, Children's Medical Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran
| |
Collapse
|
9
|
Beckmann N, Kadow S, Schumacher F, Göthert JR, Kesper S, Draeger A, Schulz-Schaeffer WJ, Wang J, Becker JU, Kramer M, Kühn C, Kleuser B, Becker KA, Gulbins E, Carpinteiro A. Pathological manifestations of Farber disease in a new mouse model. Biol Chem 2019; 399:1183-1202. [PMID: 29908121 DOI: 10.1515/hsz-2018-0170] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/07/2018] [Indexed: 11/15/2022]
Abstract
Farber disease (FD) is a rare lysosomal storage disorder resulting from acid ceramidase deficiency and subsequent ceramide accumulation. No treatments are clinically available and affected patients have a severely shortened lifespan. Due to the low incidence, the pathogenesis of FD is still poorly understood. Here, we report a novel acid ceramidase mutant mouse model that enables the study of pathogenic mechanisms of FD and ceramide accumulation. Asah1tmEx1 mice were generated by deletion of the acid ceramidase signal peptide sequence. The effects on lysosomal targeting and activity of the enzyme were assessed. Ceramide and sphingomyelin levels were quantified by liquid chromatography tandem-mass spectrometry (LC-MS/MS) and disease manifestations in several organ systems were analyzed by histology and biochemistry. We show that deletion of the signal peptide sequence disrupts lysosomal targeting and enzyme activity, resulting in ceramide and sphingomyelin accumulation. The affected mice fail to thrive and die early. Histiocytic infiltrations were observed in many tissues, as well as lung inflammation, liver fibrosis, muscular disease manifestations and mild kidney injury. Our new mouse model mirrors human FD and thus offers further insights into the pathogenesis of this disease. In the future, it may also facilitate the development of urgently needed therapies.
Collapse
Affiliation(s)
- Nadine Beckmann
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Stephanie Kadow
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Fabian Schumacher
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany.,Department of Toxicology, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Joachim R Göthert
- Department of Hematology, University Hospital Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Stefanie Kesper
- Department of Hematology, University Hospital Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Annette Draeger
- Institute of Anatomy, University of Bern, Baltzerstr. 2, CH-3012 Bern, Switzerland
| | - Walter J Schulz-Schaeffer
- Insitute of Neuropathology, University of the Saarland, Kirrberger Str. 100, D-66421 Homburg, Germany
| | - Jiang Wang
- Department of Pathology and Laboratory Medicine, UC Health University Hospital, 234 Goodman Street, Cincinnati, OH 45219, USA
| | - Jan U Becker
- Institute of Pathology, University Hospital Cologne, Kerpener Straße 62, D-50937 Cologne, Germany
| | - Melanie Kramer
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Claudine Kühn
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Burkhard Kleuser
- Department of Toxicology, Institute of Nutritional Science, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Katrin Anne Becker
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany.,Department of Surgery, University of Cincinnati, 231 Albert Sabin Way, ML 0558, Cincinnati, OH 45229, USA
| | - Alexander Carpinteiro
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstraße 55, D-45147 Essen, Germany.,Department of Hematology, University Hospital Essen, Hufelandstraße 55, D-45147 Essen, Germany
| |
Collapse
|
10
|
A new case of SMA phenotype without epilepsy due to biallelic variants in ASAH1. Eur J Hum Genet 2018; 27:337-339. [PMID: 30291339 DOI: 10.1038/s41431-018-0250-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 08/03/2018] [Accepted: 08/09/2018] [Indexed: 11/08/2022] Open
|
11
|
Myers KA, Johnstone DL, Dyment DA. Epilepsy genetics: Current knowledge, applications, and future directions. Clin Genet 2018; 95:95-111. [PMID: 29992546 DOI: 10.1111/cge.13414] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 07/03/2018] [Accepted: 07/06/2018] [Indexed: 12/12/2022]
Abstract
The rapid pace of disease gene discovery has resulted in tremendous advances in the field of epilepsy genetics. Clinical testing with comprehensive gene panels, exomes, and genomes are now available and have led to higher diagnostic rates and insights into the underlying disease processes. As such, the contribution to the care of patients by medical geneticists, neurogeneticists and genetic counselors are significant; the dysmorphic examination, the necessary pre- and post-test counseling, the selection of the appropriate next-generation sequencing-based test(s), and the interpretation of sequencing results require a care provider to have a comprehensive working knowledge of the strengths and limitations of the available testing technologies. As the underlying mechanisms of the encephalopathies and epilepsies are better understood, there may be opportunities for the development of novel therapies based on an individual's own specific genotype. Drug screening with in vitro and in vivo models of epilepsy can potentially facilitate new treatment strategies. The future of epilepsy genetics will also probably include other-omic approaches such as transcriptomes, metabolomes, and the expanded use of whole genome sequencing to further improve our understanding of epilepsy and provide better care for those with the disease.
Collapse
Affiliation(s)
- K A Myers
- Department of Pediatrics, University of McGill, Montreal, Canada.,Research Institute of the McGill University Health Centre, Montreal, Canada
| | - D L Johnstone
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Department of Genetics, Children's Hospital of Eastern Ontario, Ottawa, Canada
| |
Collapse
|
12
|
Yu FPS, Amintas S, Levade T, Medin JA. Acid ceramidase deficiency: Farber disease and SMA-PME. Orphanet J Rare Dis 2018; 13:121. [PMID: 30029679 PMCID: PMC6053731 DOI: 10.1186/s13023-018-0845-z] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/14/2018] [Indexed: 12/29/2022] Open
Abstract
Acid ceramidase (ACDase) deficiency is a spectrum of disorders that includes a rare lysosomal storage disorder called Farber disease (FD) and a rare epileptic disorder called spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). Both disorders are caused by mutations in the ASAH1 gene that encodes the lysosomal hydrolase that breaks down the bioactive lipid ceramide. To date, there have been fewer than 200 reported cases of FD and SMA-PME in the literature. Typical textbook manifestations of classical FD include the formation of subcutaneous nodules, accumulation of joint contractures, and development of a hoarse voice. In reality, however, the clinical presentation is much broader. Patients may develop severe pathologies leading to death in infancy or may develop attenuated forms of the disorder wherein they are often misdiagnosed or not diagnosed until adulthood. A clinical variability also exists for SMA-PME, in which patients develop progressive muscle weakness and seizures. Currently, there is no known cure for FD or for SMA-PME. The main treatment is symptom management. In rare cases, treatment may include surgery or hematopoietic stem cell transplantation. Research using disease models has provided insights into the pathology as well as the role of ACDase in the development of these conditions. Recent studies have highlighted possible biomarkers for an effective diagnosis of ACDase deficiency. Ongoing work is being conducted to evaluate the use of recombinant human ACDase (rhACDase) for the treatment of FD. Finally, gene therapy strategies for the treatment of ACDase deficiency are actively being pursued. This review highlights the broad clinical definition and outlines key studies that have improved our understanding of inherited ACDase deficiency-related conditions.
Collapse
Affiliation(s)
- Fabian P S Yu
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Samuel Amintas
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Thierry Levade
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France. .,INSERM UMR1037 CRCT, Université de Toulouse, Toulouse, France.
| | - Jeffrey A Medin
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada. .,Departments of Pediatrics and Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
| |
Collapse
|
13
|
Smith HS, Swint JM, Lalani SR, Yamal JM, de Oliveira Otto MC, Castellanos S, Taylor A, Lee BH, Russell HV. Clinical Application of Genome and Exome Sequencing as a Diagnostic Tool for Pediatric Patients: a Scoping Review of the Literature. Genet Med 2018; 21:3-16. [PMID: 29760485 DOI: 10.1038/s41436-018-0024-6] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/20/2018] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Availability of clinical genomic sequencing (CGS) has generated questions about the value of genome and exome sequencing as a diagnostic tool. Analysis of reported CGS application can inform uptake and direct further research. This scoping literature review aims to synthesize evidence on the clinical and economic impact of CGS. METHODS PubMed, Embase, and Cochrane were searched for peer-reviewed articles published between 2009 and 2017 on diagnostic CGS for infant and pediatric patients. Articles were classified according to sample size and whether economic evaluation was a primary research objective. Data on patient characteristics, clinical setting, and outcomes were extracted and narratively synthesized. RESULTS Of 171 included articles, 131 were case reports, 40 were aggregate analyses, and 4 had a primary economic evaluation aim. Diagnostic yield was the only consistently reported outcome. Median diagnostic yield in aggregate analyses was 33.2% but varied by broad clinical categories and test type. CONCLUSION Reported CGS use has rapidly increased and spans diverse clinical settings and patient phenotypes. Economic evaluations support the cost-saving potential of diagnostic CGS. Multidisciplinary implementation research, including more robust outcome measurement and economic evaluation, is needed to demonstrate clinical utility and cost-effectiveness of CGS.
Collapse
Affiliation(s)
- Hadley Stevens Smith
- Baylor College of Medicine, The University of Texas School of Public Health, Houston, Texas, USA
| | - J Michael Swint
- The University of Texas School of Public Health, The Center for Clinical Research and Evidence-Based Medicine, The University of Texas McGovern Medical School, Houston, Texas, USA
| | - Seema R Lalani
- Baylor College of Medicine, Baylor Genetics Laboratory, Houston, Texas, USA
| | - Jose-Miguel Yamal
- The University of Texas School of Public Health, Houston, Texas, USA
| | | | | | - Amy Taylor
- Texas Medical Center Library, Houston, Texas, USA
| | | | - Heidi V Russell
- Texas Children's Hospital, Baylor College of Medicine, Houston, Texas, USA
| |
Collapse
|
14
|
Olsen ASB, Færgeman NJ. Sphingolipids: membrane microdomains in brain development, function and neurological diseases. Open Biol 2018; 7:rsob.170069. [PMID: 28566300 PMCID: PMC5451547 DOI: 10.1098/rsob.170069] [Citation(s) in RCA: 189] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 04/30/2017] [Indexed: 12/11/2022] Open
Abstract
Sphingolipids are highly enriched in the nervous system where they are pivotal constituents of the plasma membranes and are important for proper brain development and functions. Sphingolipids are not merely structural elements, but are also recognized as regulators of cellular events by their ability to form microdomains in the plasma membrane. The significance of such compartmentalization spans broadly from being involved in differentiation of neurons and synaptic transmission to neuronal–glial interactions and myelin stability. Thus, perturbations of the sphingolipid metabolism can lead to rearrangements in the plasma membrane, which has been linked to the development of various neurological diseases. Studying microdomains and their functions has for a long time been synonymous with studying the role of cholesterol. However, it is becoming increasingly clear that microdomains are very heterogeneous, which among others can be ascribed to the vast number of sphingolipids. In this review, we discuss the importance of microdomains with emphasis on sphingolipids in brain development and function as well as how disruption of the sphingolipid metabolism (and hence microdomains) contributes to the pathogenesis of several neurological diseases.
Collapse
Affiliation(s)
- Anne S B Olsen
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Nils J Færgeman
- Villum Center for Bioanalytical Sciences, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| |
Collapse
|
15
|
Yildiz EP, Yesil G, Bektas G, Caliskan M, Tatlı B, Aydinli N, Ozmen M. Spinal muscular atrophy with progressive myoclonic epilepsy linked to mutations in ASAH1. Clin Neurol Neurosurg 2017; 164:47-49. [PMID: 29169047 DOI: 10.1016/j.clineuro.2017.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 11/08/2017] [Accepted: 11/13/2017] [Indexed: 11/26/2022]
Abstract
Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME), a rare disorder caused by mutation in the ASAH1 gene, is characterized by progressive muscle weakness and intractable epilepsy. The literature about SMA-PME is very rare and most of the time limited to case reports. Mutation in the ASAH1 gene is also found in another rare syndrome which is Farber disease. We report a case of a 13.5-year-old girl with SMA-PME associated with ASAH1 gene mutation. She presented with progressive muscle weakness, tremor, seizure, and cognitive impairment. Clinical features and electrophysiological investigations revealed a motor neuron disease and generalized epilepsy. The marked difference in disease manifestations may explain why Farber and SMA-PME diseases were not suspected of being allelic conditions. SMA-PME cases with ASAH1 mutation could be treated using therapeutic studies regarding Farber disease. In patients with undefined PME or lower motor neuron disease cases, ASAH1 mutation scans should be studied.
Collapse
Affiliation(s)
- Edibe Pembegül Yildiz
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey.
| | - Gözde Yesil
- Department of Medical Genetics, Bezmi Alem Vakif University Faculty of Medicine, Istanbul, Turkey
| | - Gonca Bektas
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Mine Caliskan
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Burak Tatlı
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Nur Aydinli
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| | - Meral Ozmen
- Division of Pediatric Neurology, Department of Pediatrics, Istanbul University, Istanbul Faculty of Medicine, Istanbul, Turkey
| |
Collapse
|
16
|
de Souza PVS, Bortholin T, Naylor FGM, Chieia MAT, de Rezende Pinto WBV, Oliveira ASB. Motor neuron disease in inherited neurometabolic disorders. Rev Neurol (Paris) 2017; 174:115-124. [PMID: 29128155 DOI: 10.1016/j.neurol.2017.06.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/29/2017] [Accepted: 06/15/2017] [Indexed: 01/18/2023]
Abstract
Inherited neurometabolic disorders represent a growing group of inborn errors of metabolism that present with major neurological symptoms or a complex spectrum of symptoms dominated by central or peripheral nervous system dysfunction. Many neurological presentations may arise from the same metabolic defect, especially in autosomal-recessive inherited disorders. Motor neuron disease (MND), mainly represented by amyotrophic lateral sclerosis, may also result from various inborn errors of metabolism, some of which may represent potentially treatable conditions, thereby emphasizing the importance of recognizing such diseases. The present review discusses the most important neurometabolic disorders presenting with motor neuron (lower and/or upper) dysfunction as the key clinical and neuropathological feature.
Collapse
Affiliation(s)
- P Victor Sgobbi de Souza
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - T Bortholin
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - F George Monteiro Naylor
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - M Antônio Troccoli Chieia
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - W Bocca Vieira de Rezende Pinto
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
| | - A Souza Bulle Oliveira
- Division of Neuromuscular Diseases, Department of Neurology and Neurosurgery, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| |
Collapse
|
17
|
Dodge JC. Lipid Involvement in Neurodegenerative Diseases of the Motor System: Insights from Lysosomal Storage Diseases. Front Mol Neurosci 2017; 10:356. [PMID: 29163032 PMCID: PMC5675881 DOI: 10.3389/fnmol.2017.00356] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 10/19/2017] [Indexed: 12/11/2022] Open
Abstract
Lysosomal storage diseases (LSDs) are a heterogeneous group of rare inherited metabolic diseases that are frequently triggered by the accumulation of lipids inside organelles of the endosomal-autophagic-lysosomal system (EALS). There is now a growing realization that disrupted lysosomal homeostasis (i.e., lysosomal cacostasis) also contributes to more common neurodegenerative disorders such as Parkinson disease (PD). Lipid deposition within the EALS may also participate in the pathogenesis of some additional neurodegenerative diseases of the motor system. Here, I will highlight the lipid abnormalities and clinical manifestations that are common to LSDs and several diseases of the motor system, including amyotrophic lateral sclerosis (ALS), atypical forms of spinal muscular atrophy, Charcot-Marie-Tooth disease (CMT), hereditary spastic paraplegia (HSP), multiple system atrophy (MSA), PD and spinocerebellar ataxia (SCA). Elucidating the underlying basis of intracellular lipid mislocalization as well as its consequences in each of these disorders will likely provide innovative targets for therapeutic research.
Collapse
Affiliation(s)
- James C Dodge
- Neuroscience Therapeutic Area, Sanofi, Framingham, MA, United States
| |
Collapse
|
18
|
Schuchman EH, Mitchell J, Solyom A. Morbidity and mortality associated with Farber disease and prospects for therapy. Expert Opin Orphan Drugs 2017. [DOI: 10.1080/21678707.2017.1359086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Edward H. Schuchman
- Genetic Disease Foundation-Francis Crick Professor, Department of Genetics & Genomic Sciences, Icahn School of Medicine, New York, NY, USA
| | - John Mitchell
- Division of Pediatric Endocrinology, Montreal Children’s Hospital, Montreal, QC, Canada
| | - Alex Solyom
- Clinical Research & Patient Affairs, Enzyvant, Basel, Switzerland
| |
Collapse
|
19
|
Cozma C, Iurașcu MI, Eichler S, Hovakimyan M, Brandau O, Zielke S, Böttcher T, Giese AK, Lukas J, Rolfs A. C26-Ceramide as highly sensitive biomarker for the diagnosis of Farber Disease. Sci Rep 2017; 7:6149. [PMID: 28733637 PMCID: PMC5522391 DOI: 10.1038/s41598-017-06604-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 06/15/2017] [Indexed: 12/31/2022] Open
Abstract
Farber disease (FD) is a rare autosomal recessive disease caused by mutations in the acid ceramidase gene (ASAH1). Low ceramidase activity results in the accumulation of fatty substances, mainly ceramides. Hallmark symptoms at clinical level are periarticular nodules, lipogranulomas, swollen and painful joints and a hoarse voice. FD phenotypes are heterogeneous varying from mild to very severe cases, with the patients not surviving past their first year of life. The diagnostic aspects of FD are poorly developed due to the rarity of the disease. In the present study, the screening for ceramides and related molecules was performed in Farber affected patients (n = 10), carriers (n = 11) and control individuals (n = 192). This study has the highest number of enrolled Farber patients and carriers reported to present. Liquid chromatography multiple reaction mass spectrometry (LC/MRM-MS) studies revealed that the ceramide C26:0 and especially its isoform 1 is a highly sensitive and specific biomarker for FD (p < 0.0001). The new biomarker can be determined directly in the dried blood spot extracts with low sample consumption. This allows for easy sample preparation, high reproducibility and use in high throughput screenings.
Collapse
Affiliation(s)
- Claudia Cozma
- Centogene AG, Schillingallee 68, 18057, Rostock, Germany.
| | | | | | | | - Oliver Brandau
- Centogene AG, Schillingallee 68, 18057, Rostock, Germany
| | - Susanne Zielke
- Albrecht-Kossel-Institute for Neurodegeneration, Rostock University Medical Centre, Gehlsheimerstraße 20, 18147, Rostock, Germany
| | - Tobias Böttcher
- Albrecht-Kossel-Institute for Neurodegeneration, Rostock University Medical Centre, Gehlsheimerstraße 20, 18147, Rostock, Germany
| | - Anne-Katrin Giese
- Albrecht-Kossel-Institute for Neurodegeneration, Rostock University Medical Centre, Gehlsheimerstraße 20, 18147, Rostock, Germany
| | - Jan Lukas
- Albrecht-Kossel-Institute for Neurodegeneration, Rostock University Medical Centre, Gehlsheimerstraße 20, 18147, Rostock, Germany
| | - Arndt Rolfs
- Centogene AG, Schillingallee 68, 18057, Rostock, Germany.,Albrecht-Kossel-Institute for Neurodegeneration, Rostock University Medical Centre, Gehlsheimerstraße 20, 18147, Rostock, Germany
| |
Collapse
|
20
|
Kernohan KD, Frésard L, Zappala Z, Hartley T, Smith KS, Wagner J, Xu H, McBride A, Bourque PR, Bennett SAL, Dyment DA, Boycott KM, Montgomery SB, Chardon JW. Whole-transcriptome sequencing in blood provides a diagnosis of spinal muscular atrophy with progressive myoclonic epilepsy. Hum Mutat 2017; 38:611-614. [PMID: 28251733 PMCID: PMC5889109 DOI: 10.1002/humu.23211] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 01/19/2017] [Accepted: 02/21/2017] [Indexed: 12/22/2022]
Abstract
At least 15% of the disease-causing mutations affect mRNA splicing. Many splicing mutations are missed in a clinical setting due to limitations of in silico prediction algorithms or their location in noncoding regions. Whole-transcriptome sequencing is a promising new tool to identify these mutations; however, it will be a challenge to obtain disease-relevant tissue for RNA. Here, we describe an individual with a sporadic atypical spinal muscular atrophy, in whom clinical DNA sequencing reported one pathogenic ASAH1 mutation (c.458A>G;p.Tyr153Cys). Transcriptome sequencing on patient leukocytes identified a highly significant and atypical ASAH1 isoform not explained by c.458A>G(p<10-16 ). Subsequent Sanger-sequencing identified the splice mutation responsible for the isoform (c.504A>C;p.Lys168Asn) and provided a molecular diagnosis of autosomal-recessive spinal muscular atrophy with progressive myoclonic epilepsy. Our findings demonstrate the utility of RNA sequencing from blood to identify splice-impacting disease mutations for nonhematological conditions, providing a diagnosis for these otherwise unsolved patients.
Collapse
Affiliation(s)
- Kristin D. Kernohan
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Laure Frésard
- Department of Pathology, Stanford University, Stanford, California
| | - Zachary Zappala
- Department of Pathology, Stanford University, Stanford, California
- Department of Genetics, Stanford University, Stanford, California
| | - Taila Hartley
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kevin S. Smith
- Department of Pathology, Stanford University, Stanford, California
| | - Justin Wagner
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Hongbin Xu
- Department of BMI, University of Ottawa, Ottawa, Ontario, Canada
| | - Arran McBride
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | | | | | | | - David A. Dyment
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Kym M. Boycott
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
| | - Stephen B. Montgomery
- Department of Pathology, Stanford University, Stanford, California
- Department of Genetics, Stanford University, Stanford, California
| | - Jodi Warman Chardon
- Department of Genetics, Children’s Hospital of Eastern Ontario, Ottawa, Ontario, Canada
- Children’s Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, Canada
- Division of Neurology, The Ottawa Hospital, Ottawa, Ontario, Canada
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Centre for Neuromuscular Disease (CNMD), University of Ottawa, Ottawa, Ontario, Canada
| |
Collapse
|
21
|
Abstract
Paediatric motor neuron diseases encompass a group of neurodegenerative diseases characterised by the onset of muscle weakness and atrophy before the age of 18 years, attributable to motor neuron loss across various neuronal networks in the brain and spinal cord. While the genetic underpinnings are diverse, advances in next generation sequencing have transformed diagnostic paradigms. This has reinforced the clinical phenotyping and molecular genetic expertise required to navigate the complexities of such diagnoses. In turn, improved genetic technology and subsequent gene identification have enabled further insights into the mechanisms of motor neuron degeneration and how these diseases form part of a neurodegenerative disorder spectrum. Common pathophysiologies include abnormalities in axonal architecture and function, RNA processing, and protein quality control. This review incorporates an overview of the clinical manifestations, genetics, and pathophysiology of inherited paediatric motor neuron disorders beyond classic SMN1-related spinal muscular atrophy and describes recent advances in next generation sequencing and its clinical application. Specific disease-modifying treatment is becoming a clinical reality in some disorders of the motor neuron highlighting the importance of a timely and specific diagnosis.
Collapse
|
22
|
Sikora J, Dworski S, Jones EE, Kamani MA, Micsenyi MC, Sawada T, Le Faouder P, Bertrand-Michel J, Dupuy A, Dunn CK, Xuan ICY, Casas J, Fabrias G, Hampson DR, Levade T, Drake RR, Medin JA, Walkley SU. Acid Ceramidase Deficiency in Mice Results in a Broad Range of Central Nervous System Abnormalities. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:864-883. [PMID: 28342444 DOI: 10.1016/j.ajpath.2016.12.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 12/02/2016] [Accepted: 12/08/2016] [Indexed: 12/30/2022]
Abstract
Farber disease is a rare autosomal recessive disorder caused by acid ceramidase deficiency that usually presents as early-onset progressive visceral and neurologic disease. To understand the neurologic abnormality, we investigated behavioral, biochemical, and cellular abnormalities in the central nervous system of Asah1P361R/P361R mice, which serve as a model of Farber disease. Behaviorally, the mutant mice had reduced voluntary locomotion and exploration, increased thigmotaxis, abnormal spectra of basic behavioral activities, impaired muscle grip strength, and defects in motor coordination. A few mutant mice developed hydrocephalus. Mass spectrometry revealed elevations of ceramides, hydroxy-ceramides, dihydroceramides, sphingosine, dihexosylceramides, and monosialodihexosylganglioside in the brain. The highest accumulation was in hydroxy-ceramides. Storage compound distribution was analyzed by mass spectrometry imaging and morphologic analyses and revealed involvement of a wide range of central nervous system cell types (eg, neurons, endothelial cells, and choroid plexus cells), most notably microglia and/or macrophages. Coalescing and mostly perivascular granuloma-like accumulations of storage-laden CD68+ microglia and/or macrophages were seen as early as 3 weeks of age and located preferentially in white matter, periventricular zones, and meninges. Neurodegeneration was also evident in specific cerebral areas in late disease. Overall, our central nervous system studies in Asah1P361R/P361R mice substantially extend the understanding of human Farber disease and suggest that this model can be used to advance therapeutic approaches for this currently untreatable disorder.
Collapse
Affiliation(s)
- Jakub Sikora
- Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, New York; Institute of Inherited Metabolic Disorders, Charles University, 1st Faculty of Medicine, Prague, Czech Republic; Institute of Pathology, Charles University, 1st Faculty of Medicine, Prague, Czech Republic
| | - Shaalee Dworski
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - E Ellen Jones
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina
| | | | - Matthew C Micsenyi
- Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Tomo Sawada
- Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, New York
| | - Pauline Le Faouder
- MetaToul-Lipidomic Facility-MetaboHUB, INSERM UMR1048, Institute of Cardiovascular and Metabolic Diseases, Université Paul Sabatier-Toulouse III, Toulouse, France
| | - Justine Bertrand-Michel
- MetaToul-Lipidomic Facility-MetaboHUB, INSERM UMR1048, Institute of Cardiovascular and Metabolic Diseases, Université Paul Sabatier-Toulouse III, Toulouse, France
| | - Aude Dupuy
- MetaToul-Lipidomic Facility-MetaboHUB, INSERM UMR1048, Institute of Cardiovascular and Metabolic Diseases, Université Paul Sabatier-Toulouse III, Toulouse, France
| | | | - Ingrid Cong Yang Xuan
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Josefina Casas
- Research Unit on Bioactive Molecules, Department of Biomedicinal Chemistry, Institute for Advanced Chemistry of Catalonia, Spanish National Research Council, Barcelona, Spain
| | - Gemma Fabrias
- Research Unit on Bioactive Molecules, Department of Biomedicinal Chemistry, Institute for Advanced Chemistry of Catalonia, Spanish National Research Council, Barcelona, Spain
| | - David R Hampson
- Department of Pharmaceutical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Thierry Levade
- INSERM UMR1037, Cancer Research Center of Toulouse, Universite Toulouse III Paul-Sabatier, Toulouse, France; Metabolic Biochemistry Laboratory, Federative Institute of Biology, Centre Hospitalier Universitaire de Toulouse, Toulouse, France
| | - Richard R Drake
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, South Carolina
| | - Jeffrey A Medin
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; University Health Network, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Medical College of Wisconsin, Milwaukee, Wisconsin.
| | - Steven U Walkley
- Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Intellectual and Developmental Disabilities Research Center, Albert Einstein College of Medicine, Bronx, New York.
| |
Collapse
|
23
|
Dworski S, Lu P, Khan A, Maranda B, Mitchell JJ, Parini R, Di Rocco M, Hugle B, Yoshimitsu M, Magnusson B, Makay B, Arslan N, Guelbert N, Ehlert K, Jarisch A, Gardner-Medwin J, Dagher R, Terreri MT, Lorenco CM, Barillas-Arias L, Tanpaiboon P, Solyom A, Norris JS, He X, Schuchman EH, Levade T, Medin JA. Acid Ceramidase Deficiency is characterized by a unique plasma cytokine and ceramide profile that is altered by therapy. Biochim Biophys Acta Mol Basis Dis 2016; 1863:386-394. [PMID: 27915031 DOI: 10.1016/j.bbadis.2016.11.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Revised: 11/17/2016] [Accepted: 11/30/2016] [Indexed: 12/21/2022]
Abstract
Acid Ceramidase Deficiency (Farber disease, FD) is an ultra-rare Lysosomal Storage Disorder that is poorly understood and often misdiagnosed as Juvenile Idiopathic Arthritis (JIA). Hallmarks of FD are accumulation of ceramides, widespread macrophage infiltration, splenomegaly, and lymphocytosis. The cytokines involved in this abnormal hematopoietic state are unknown. There are dozens of ceramide species and derivatives, but the specific ones that accumulate in FD have not been investigated. We used a multiplex assay to analyze cytokines and mass spectrometry to analyze ceramides in plasma from patients and mice with FD, controls, Farber patients treated by hematopoietic stem cell transplantation (HSCT), JIA patients, and patients with Gaucher disease. KC, MIP-1α, and MCP-1 were sequentially upregulated in plasma from FD mice. MCP-1, IL-10, IL-6, IL-12, and VEGF levels were elevated in plasma from Farber patients but not in control or JIA patients. C16-Ceramide (C16-Cer) and dhC16-Cer were upregulated in plasma from FD mice. a-OH-C18-Cer, dhC12-Cer, dhC24:1-Cer, and C22:1-Cer-1P accumulated in plasma from patients with FD. Most cytokines and only a-OH-C18-Cer returned to baseline levels in HSCT-treated Farber patients. Sphingosines were not altered. Chitotriosidase activity was also relatively low. A unique cytokine and ceramide profile was seen in the plasma of Farber patients that was not observed in plasma from HSCT-treated Farber patients, JIA patients, or Gaucher patients. The cytokine profile can potentially be used to prevent misdiagnosis of Farber as JIA and to monitor the response to treatment. Further understanding of why these signaling molecules and lipids are elevated can lead to better understanding of the etiology and pathophysiology of FD and inform development of future treatments.
Collapse
Affiliation(s)
- Shaalee Dworski
- Institute of Medical Science, University of Toronto, Toronto M5G 1L7, Canada
| | - Ping Lu
- Department of Microbiology and Immunology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425-5040, USA
| | - Aneal Khan
- Medical Genetics and Pediatrics, University of Calgary, Alberta Children's Hospital, Calgary T3B 6A8, Canada
| | - Bruno Maranda
- Department of Genetics, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke J1G 2E8, Canada
| | - John J Mitchell
- Department of Medical Genetics, McGill University, Montréal H3A 0G4, Canada; Department of Pediatrics, McGill University, Montréal H3A 0G4, Canada
| | - Rossella Parini
- Pediatric Department, University Milano Bicocca, San Gerardo Hospital, Monza 20126, Italy
| | | | - Boris Hugle
- German Center for Paediatric and Adolescent Rheumatology, Garmisch-Partenkirchen 82467, Germany
| | - Makoto Yoshimitsu
- Division of Hematology and Immunology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544, Japan
| | - Bo Magnusson
- Pediatric Rheumatology, Karolinska University Hospital, Stockholm 171 76, Sweden
| | - Balahan Makay
- Pediatric Rheumatology, Dokuz Eylul University, Izmir 35210, Turkey
| | - Nur Arslan
- Gastroenterology and Metabolic Diseases, Dokuz Eylul University, Izmir 35210, Turkey
| | | | - Karoline Ehlert
- Department of Paediatric Oncology and Haematology, Medical University of Greifswald, Greifswald 17475, Germany
| | - Andrea Jarisch
- Department of Paediatric Oncology and Haematology, Goethe University, Frankfurt 60323, Germany
| | - Janet Gardner-Medwin
- Pediatric Rheumatology, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - Rawane Dagher
- Pediatric Rheumatology, Notre Dame De Secours University Hospital, Byblos, Lebanon
| | - Maria Teresa Terreri
- Pediatric Rheumatology, Federal University of Sao Paulo, Sao Paulo 04023-900, Brazil
| | - Charles Marques Lorenco
- Neurogenetics, Hospital of Ribeirao Preto, University of Sao Paulo, Sao Paulo 04023-900, Brazil
| | - Lilianna Barillas-Arias
- Pediatric Rheumatology, Bernard & Millie Duker Children's Hospital, Albany Medical Center, Albany, NY 12208, USA
| | - Pranoot Tanpaiboon
- Metabolic Diseases, Children's National Health System, Washington, DC 20010, USA
| | | | - James S Norris
- Department of Microbiology and Immunology, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425-5040, USA
| | - Xingxuan He
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Edward H Schuchman
- Plexcera Therapeutics, New York, NY 10029-6574, USA; Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029-6574, USA
| | - Thierry Levade
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, and INSERM UMR1037 CRCT, Toulouse 31037 Cedex 1, France
| | - Jeffrey A Medin
- Institute of Medical Science, University of Toronto, Toronto M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto M5G 1L7, Canada; University Health Network, Toronto M5G 1L7, Canada; Medical College of Wisconsin, Milwaukee, WI 53226, USA.
| |
Collapse
|
24
|
Teoh HL, Solyom A, Schuchman EH, Mowat D, Roscioli T, Farrar M, Sampaio H. Polyarticular Arthritis and Spinal Muscular Atrophy in Acid Ceramidase Deficiency. Pediatrics 2016; 138:peds.2016-1068. [PMID: 27650050 DOI: 10.1542/peds.2016-1068] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/21/2016] [Indexed: 11/24/2022] Open
Abstract
Survival of motor neuron 1-------negative spinal muscular atrophy (SMA) is heterogeneous and remains a diagnostic challenge. The clinical spectrum continues to expand and ∼33 genes have been identified to date. The present report describes a 9-year-old girl with novel clinical phenotype of a patient with polyarticular arthritis followed by symptoms of SMA due to acid ceramidase deficiency. Whole exome sequencing identified compound heterozygous pathogenic mutation in the N-acylsphingosine amidohydrolase 1 gene. Functional assay with leukocyte acid ceramidase activity showed a decreased level in the proband confirming pathogenicity of the mutations. Mutations of N-acylsphingosine amidohydrolase 1 are known to separately cause Farber disease (arthritis, subcutaneous nodules, and dysphonia) or SMA with progressive myoclonic epilepsy. The present combined phenotype is novel, bringing together SMA with progressive myoclonic epilepsy and Farber disease and establishing a phenotypic spectrum. Acid ceramidase deficiency is an important consideration in patients presenting with polyarticular arthritis and motor neuron disease.
Collapse
Affiliation(s)
- Hooi Ling Teoh
- Departments of Neurology and.,Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Alexander Solyom
- Clinical Research, Plexcera Therapeutics LLC, New York, New York
| | - Edward H Schuchman
- Department of Genetic and Genomic Sciences, Icahn School of Medicine at Mt. Sinai, New York, New York
| | - David Mowat
- Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia.,Medical Genetics, Sydney Children's Hospital, Sydney Australia
| | - Tony Roscioli
- Medical Genetics, Sydney Children's Hospital, Sydney Australia.,St Vincent's Clinical School, University of New South Wales, Darlinghurst, Australia; and.,Kinghorn Centre for Clinical Genomics, Darlinghurst, New South Wales, Australia
| | - Michelle Farrar
- Departments of Neurology and.,Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| | - Hugo Sampaio
- Departments of Neurology and .,Discipline of Paediatrics, School of Women's and Children's Health, UNSW Medicine, The University of New South Wales, Sydney, Australia
| |
Collapse
|
25
|
Oguz Akarsu E, Tekturk P, Yapici Z, Tepgec F, Uyguner ZO, Baykan B. Eyelid myoclonic status epilepticus: A rare phenotype in spinal muscular atrophy with progressive myoclonic epilepsy associated with ASAH1 gene mutation. Seizure 2016; 42:49-51. [PMID: 27723502 DOI: 10.1016/j.seizure.2016.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Revised: 09/07/2016] [Accepted: 09/10/2016] [Indexed: 11/28/2022] Open
Affiliation(s)
- Emel Oguz Akarsu
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey.
| | - Pınar Tekturk
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Zuhal Yapici
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Fatih Tepgec
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Genetics, Istanbul, Turkey
| | - Z Oya Uyguner
- Istanbul University, Istanbul Faculty of Medicine, Department of Medical Genetics, Istanbul, Turkey
| | - Betul Baykan
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| |
Collapse
|
26
|
Hamilton A, Tétreault M, Dyment DA, Zou R, Kernohan K, Geraghty MT, Hartley T, Boycott KM. Concordance between whole-exome sequencing and clinical Sanger sequencing: implications for patient care. Mol Genet Genomic Med 2016; 4:504-12. [PMID: 27652278 PMCID: PMC5023935 DOI: 10.1002/mgg3.223] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 04/05/2016] [Accepted: 04/07/2016] [Indexed: 12/12/2022] Open
Abstract
The clinical translation of next‐generation sequencing has created a paradigm shift in the diagnostic assessment of individuals with suspected rare genetic diseases. Whole‐exome sequencing (WES) simultaneously examines the majority of the coding portion of the genome and is rapidly becoming accepted as an efficient alternative to clinical Sanger sequencing for diagnosing genetically heterogeneous disorders. Among reports of the clinical and diagnostic utility of WES, few studies to date have directly compared its concordance to Sanger sequencing, which is considered the clinical “gold standard”. We performed a direct comparison of 391 coding and noncoding polymorphisms and variants of unknown significance identified by clinical Sanger sequencing to the WES results of 26 patients. Of the 150 well‐covered coding variants identified by Sanger sequencing, 146 (97.3%) were also reported by WES. Nine genes were excluded from the comparison due to consistently low coverage in WES, which might be attributed to the use of older exome capture kits. We performed confirmatory Sanger sequencing of discordant variants; including five variants with discordant bases and four with discordant zygosity. Confirmatory Sanger sequencing supported the original Sanger report for three of the five discordant bases, one was shown to be a false positive supporting the WES data, and one result differed from both the Sanger and WES data. Two of the discordant zygosity results supported Sanger and the other two supported WES data. We report high concordance for well‐covered coding variants, supporting the use of WES as a screening tool for heterogeneous disorders, and recommend the use of supplementary Sanger sequencing for poorly‐covered genes when the clinical suspicion is high. Importantly, despite remaining difficulties with achieving complete coverage of the whole exome, 10 (38.5%) of the 26 compared patients were diagnosed through WES.
Collapse
Affiliation(s)
- Alison Hamilton
- Children's Hospital of Eastern Ontario Research Institute University of Ottawa Ottawa Ontario Canada
| | - Martine Tétreault
- Department of Human Genetics McGill UniversityMontréalQuébecCanada; McGill University and Genome Québec Innovation CenterMontréalQuébecCanada
| | - David A Dyment
- Children's Hospital of Eastern Ontario Research InstituteUniversity of OttawaOttawaOntarioCanada; Department of GeneticsChildren's Hospital of Eastern Ontario ResearchOttawaOntarioCanada
| | - Ruobing Zou
- Children's Hospital of Eastern Ontario Research Institute University of Ottawa Ottawa Ontario Canada
| | - Kristin Kernohan
- Children's Hospital of Eastern Ontario Research Institute University of Ottawa Ottawa Ontario Canada
| | - Michael T Geraghty
- Children's Hospital of Eastern Ontario Research InstituteUniversity of OttawaOttawaOntarioCanada; Division of Metabolics and Newborn ScreeningDepartment of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
| | | | | | - Taila Hartley
- Children's Hospital of Eastern Ontario Research Institute University of Ottawa Ottawa Ontario Canada
| | - Kym M Boycott
- Children's Hospital of Eastern Ontario Research InstituteUniversity of OttawaOttawaOntarioCanada; Department of GeneticsChildren's Hospital of Eastern Ontario ResearchOttawaOntarioCanada
| |
Collapse
|
27
|
Schuchman EH. Acid ceramidase and the treatment of ceramide diseases: The expanding role of enzyme replacement therapy. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1459-71. [PMID: 27155573 DOI: 10.1016/j.bbadis.2016.05.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/18/2016] [Accepted: 05/03/2016] [Indexed: 01/20/2023]
Abstract
Ceramides are a diverse group of sphingolipids that play important roles in many biological processes. Acid ceramidase (AC) is one key enzyme that regulates ceramide metabolism. Early research on AC focused on the fact that it is the enzyme deficient in the rare genetic disorder, Farber Lipogranulomatosis. Recent research has revealed that deficiency of the same enzyme is responsible for a rare form of spinal muscular atrophy associated with myoclonic epilepsy (SMA-PME). Due to their diverse role in biology, accumulation of ceramides also has been implicated in the pathobiology of many other common diseases, including infectious lung diseases, diabetes, cancers and others. This has revealed the potential of AC as a therapy for many of these diseases. This review will focus on the biology of AC and the potential role of this enzyme in the treatment of human disease.
Collapse
Affiliation(s)
- Edward H Schuchman
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
28
|
Filosto M, Aureli M, Castellotti B, Rinaldi F, Schiumarini D, Valsecchi M, Lualdi S, Mazzotti R, Pensato V, Rota S, Gellera C, Filocamo M, Padovani A. ASAH1 variant causing a mild SMA phenotype with no myoclonic epilepsy: a clinical, biochemical and molecular study. Eur J Hum Genet 2016; 24:1578-1583. [PMID: 27026573 DOI: 10.1038/ejhg.2016.28] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/03/2016] [Accepted: 03/01/2016] [Indexed: 11/09/2022] Open
Abstract
ASAH1 gene encodes for acid ceramidase that is involved in the degradation of ceramide into sphingosine and free fatty acids within lysosomes. ASAH1 variants cause both the severe and early-onset Farber disease and rare cases of spinal muscular atrophy (SMA) with progressive myoclonic epilepsy (SMA-PME), phenotypically characterized by childhood onset of proximal muscle weakness and atrophy due to spinal motor neuron degeneration followed by occurrence of severe and intractable myoclonic seizures and death in the teenage years. We studied two subjects, a 30-year-old pregnant woman and her 17-year-old sister, affected with a very slowly progressive non-5q SMA since childhood. No history of seizures or myoclonus has been reported and EEG was unremarkable. The molecular study of ASAH1 gene showed the presence of the homozygote nucleotide variation c.124A>G (r.124a>g) that causes the amino acid substitution p.Thr42Ala. Biochemical evaluation of cultured fibroblasts showed both reduction in ceramidase activity and accumulation of ceramide compared with the normal control. This study describes for the first time the association between ASAH1 variants and an adult SMA phenotype with no myoclonic epilepsy nor death in early age, thus expanding the phenotypic spectrum of ASAH1-related SMA. ASAH1 molecular analysis should be considered in the diagnostic testing of non-5q adult SMA patients.
Collapse
Affiliation(s)
- Massimiliano Filosto
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital 'Spedali Civili', Brescia, Italy
| | - Massimo Aureli
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', Milan, Italy
| | - Fabrizio Rinaldi
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital 'Spedali Civili', Brescia, Italy
| | - Domitilla Schiumarini
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Manuela Valsecchi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Susanna Lualdi
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto Giannina Gaslini, Genova, Italy
| | - Raffaella Mazzotti
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto Giannina Gaslini, Genova, Italy
| | - Viviana Pensato
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', Milan, Italy
| | - Silvia Rota
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital 'Spedali Civili', Brescia, Italy
| | - Cinzia Gellera
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico 'Carlo Besta', Milan, Italy
| | - Mirella Filocamo
- Centro di Diagnostica Genetica e Biochimica delle Malattie Metaboliche, Istituto Giannina Gaslini, Genova, Italy
| | - Alessandro Padovani
- Clinical Neurology, Section for Neuromuscular Diseases and Neuropathies, University Hospital 'Spedali Civili', Brescia, Italy
| |
Collapse
|
29
|
Frohbergh M, He X, Schuchman EH. The molecular medicine of acid ceramidase. Biol Chem 2016; 396:759-65. [PMID: 25938220 DOI: 10.1515/hsz-2014-0290] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/07/2015] [Indexed: 11/15/2022]
Abstract
Acid ceramidase (N-acylsphingosine deacylase, EC 3.5.1.23; AC) is the lipid hydrolase responsible for the degradation of ceramide into sphingosine and free fatty acids within lysosomes. The enzymatic activity was first identified over four decades ago and is deficient in two rare inherited disorders, Farber lipogranulomatosis (Farber disease) and spinal muscular atrophy with myoclonic epilepsy (SMA-PME). Importantly, AC not only hydrolyzes ceramide into sphingosine within acidic compartments, but also can synthesize ceramide from sphingosine at neutral pH, suggesting that the enzyme may have diverse functions depending on its subcellular location and the local pH. Within cells, AC exists in a complex with other lipid hydrolases and requires a polypeptide cofactor (saposin D) for full hydrolytic activity. Recent studies also have shown that AC is overexpressed in several human cancers, and that inhibition of this enzyme may be a useful cancer drug target. Aberrant AC activity has also been described in several other common diseases. The cDNA and gene (ASAH1) encoding AC have been isolated, several mouse models of AC deficiency have been constructed, and the recombinant enzyme is currently being manufactured for the treatment of Farber disease and SMA-PME. Current information concerning the biology of this enzyme and its role in human disease is reviewed within.
Collapse
|
30
|
Acid ceramidase deficiency associated with spinal muscular atrophy with progressive myoclonic epilepsy. Neuromuscul Disord 2015; 25:959-63. [PMID: 26526000 DOI: 10.1016/j.nmd.2015.09.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/03/2015] [Accepted: 09/07/2015] [Indexed: 11/22/2022]
Abstract
Spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) is an extremely rare disorder related to the lysosomal storage disease, Farber lipogranulomatosis. Both disorders are autosomal recessive conditions caused by mutations in the ASAH1 gene encoding acid ceramidase. Farber disease is associated with joint deformities, lipomatous skin nodules, and often is fatal by 2-3 years of age; while SMA-PME is characterized by childhood-onset motor neuron disease and progressive myoclonic epilepsy. We report a case of SMA-PME with a novel mutation in the ASAH1 gene encoding acid ceramidase. The proband presented with childhood-onset of diffuse muscle atrophy and hypotonia. He also had diffuse weakness with greater proximal than distal involvement. Tongue fasciculations were present and his reflexes were either diminished or absent. He ambulated with an unsteady and hesitant gait. He subsequently developed myoclonic epilepsy along with other associated features including tremor, polymyoclonus, and sensorineural hearing loss. Neurophysiological studies revealed a motor neuron disorder and generalized epilepsy. Exome sequencing analysis identified compound heterozygous variants and biochemical analysis indicated acid ceramidase activity was approximately 12 percent of normal controls. Our proband was phenotypically similar to other cases of SMA-PME, albeit with somewhat lesser severity, slower progression, and greater longevity. As lysosomal disorders are sometimes amendable to early interventions, it is important to make early diagnoses in these cases. The combination of motor neuron disease and progressive myoclonic epilepsy should prompt genetic evaluation of ASAH1.
Collapse
|
31
|
Rubboli G, Veggiotti P, Pini A, Berardinelli A, Cantalupo G, Bertini E, Tiziano FD, D'Amico A, Piazza E, Abiusi E, Fiori S, Pasini E, Darra F, Gobbi G, Michelucci R. Spinal muscular atrophy associated with progressive myoclonic epilepsy: A rare condition caused by mutations in ASAH1. Epilepsia 2015; 56:692-8. [PMID: 25847462 DOI: 10.1111/epi.12977] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2015] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To present the clinical features and the results of laboratory investigations in three patients with spinal muscular atrophy associated with progressive myoclonic epilepsy (SMA-PME), a rare condition caused by mutations in the N-acylsphingosine amidohydrosilase 1 (ASAH1) gene. METHODS The patients were submitted to clinical evaluation, neurophysiologic investigations (that included wakefulness and sleep electroencephalography [EEG], video-polygraphic recording with jerk-locked back-averaging, multimodal evoked potentials, and electromyography), brain magnetic resonance imaging (MRI), biochemical screening, muscle and skin biopsies, and molecular genetic analysis. RESULTS The main clinical features were onset in childhood with proximal muscular weakness, generalized epilepsy with absences and myoclonic seizures, cognitive impairment of variable degree; the course was progressive with muscle wasting and uncontrolled epileptic seizures. In one patient, earlier onset before the age of 2 years was associated with a more complex clinical picture, with abnormal eye movements, progressive cognitive impairment, and a more rapid and severe course. EEG/polygraphic data were consistent with PME, demonstrating generalized spike-and-wave discharges, evidence of positive and negative myoclonia, and prominent photosensitivity. In one patient, transcranial magnetic stimulation showed a hyperexcitable motor cortex, whereas somatosensory evoked potentials were unaffected. Possible involvement of the central acoustic and visual pathways was suggested by abnormal auditory and visual evoked potentials. Muscle biopsies showed typical signs of neurogenic damage. Molecular genetic analysis showed mutations of the ASAH1 gene. SIGNIFICANCE Our data indicate that SMA-PME associated with ASAH1 mutations is a genetically distinct condition with specific clinical and neurophysiologic features. Further studies are warranted to explore the role of the ASAH1 gene in muscle and brain function.
Collapse
Affiliation(s)
- Guido Rubboli
- Danish Epilepsy Center, Filadelfia/University of Copenhagen, Dianalund, Denmark.,Neurology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Pierangelo Veggiotti
- Department of Brain and Behavioral Sciences, Child Neuropsychiatry Unit, IRCCS C. Mondino National Neurological Institute, University of Pavia, Pavia, Italy
| | - Antonella Pini
- Child Neurology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Angela Berardinelli
- Child Neuropsychiatry Unit, IRCCS C. Mondino National Neurological Institute, Pavia, Italy
| | - Gaetano Cantalupo
- Department of Life and Reproduction Sciences, University of Verona, Verona, Italy
| | - Enrico Bertini
- IRCCS Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | | | - Adele D'Amico
- IRCCS Laboratory of Molecular Medicine, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - Elena Piazza
- Child Neuropsychiatry Unit, IRCCS C. Mondino National Neurological Institute, Pavia, Italy
| | - Emanuela Abiusi
- Medical Genetics Institute, Catholic University, Rome, Italy
| | - Stefania Fiori
- Medical Genetics Institute, Catholic University, Rome, Italy
| | - Elena Pasini
- Neurology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Francesca Darra
- Department of Life and Reproduction Sciences, University of Verona, Verona, Italy
| | - Giuseppe Gobbi
- Child Neurology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy
| | - Roberto Michelucci
- Neurology Unit, Bellaria Hospital, IRCCS Institute of Neurological Sciences, Bologna, Italy
| |
Collapse
|
32
|
Sabourdy F, Astudillo L, Colacios C, Dubot P, Mrad M, Ségui B, Andrieu-Abadie N, Levade T. Monogenic neurological disorders of sphingolipid metabolism. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1040-51. [PMID: 25660725 DOI: 10.1016/j.bbalip.2015.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 10/24/2022]
Abstract
Sphingolipids comprise a wide variety of molecules containing a sphingoid long-chain base that can be N-acylated. These lipids are particularly abundant in the central nervous system, being membrane components of neurons as well as non-neuronal cells. Direct evidence that these brain lipids play critical functions in brain physiology is illustrated by the dramatic consequences of genetic disturbances of their metabolism. Inherited defects of both synthesis and catabolism of sphingolipids are now identified in humans. These monogenic disorders are due to mutations in the genes encoding for the enzymes that catalyze either the formation or degradation of simple sphingolipids such as ceramides, or complex sphingolipids like glycolipids. They cause varying degrees of central nervous system dysfunction, quite similarly to the neurological disorders induced in mice by gene disruption of the corresponding enzymes. Herein, the enzyme deficiencies and metabolic alterations that underlie these diseases are reviewed. Their possible pathophysiological mechanisms and the functions played by sphingolipids one can deduce from these conditions are discussed. This article is part of a Special Issue entitled Brain Lipids.
Collapse
Affiliation(s)
- Frédérique Sabourdy
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France; Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Leonardo Astudillo
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France; Service de Médecine Interne, CHU Purpan, Toulouse, France
| | - Céline Colacios
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France
| | - Patricia Dubot
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Marguerite Mrad
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France
| | - Bruno Ségui
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France
| | - Nathalie Andrieu-Abadie
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France
| | - Thierry Levade
- Institut National de la Santé et de la Recherche Médicale (INSERM) UMR1037, Toulouse, France; Equipe Labellisée Ligue Nationale Contre le Cancer 2013, Centre de Recherches en Cancérologie de Toulouse (CRCT), Université de Toulouse-III Paul Sabatier, Toulouse, France; Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France.
| |
Collapse
|
33
|
Giráldez BG, Guerrero-López R, Ortega-Moreno L, Verdú A, Carrascosa-Romero MC, García-Campos Ó, García-Muñozguren S, Pardal-Fernández JM, Serratosa JM. Uniparental disomy as a cause of spinal muscular atrophy and progressive myoclonic epilepsy: phenotypic homogeneity due to the homozygous c.125C>T mutation in ASAH1. Neuromuscul Disord 2014; 25:222-4. [PMID: 25578555 DOI: 10.1016/j.nmd.2014.11.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/09/2014] [Accepted: 11/18/2014] [Indexed: 11/29/2022]
Abstract
Spinal muscular atrophy and progressive myoclonic epilepsy (SMAPME, OMIM#159950) is a rare autosomal recessive disorder characterized by the combination of progressive myoclonic epilepsy and muscular weakness due to lower motor neuron disease. Mutations in ASAH1, previously associated only to Farber disease, have been recently described in seven patients with SMAPME. A homozygous c.125C>T mutation was initially found in six patients with a clinical homogeneous phenotype. A heterozygous compound mutation found in an additional patient has broadened the clinical and genetic spectrum of clinical SMAPME. We report a new case of a 13-year-old girl with SMAPME with the homozygous ASAH1 c.125C>T mutation, unique in that it is due to paternal uniparental disomy. She experienced muscle weakness from the age of three due to lower motor neuron involvement that lead to severe handicap and onset in late childhood of a progressive myoclonic epilepsy. This clinical picture fully overlaps with that of previously reported patients with this mutation and supports our view that the clinical phenotype associated with the homozygous c.125C>T mutation constitutes a clinically homogenous and recognizable disease.
Collapse
Affiliation(s)
- Beatriz G Giráldez
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Rosa Guerrero-López
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Laura Ortega-Moreno
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Alfonso Verdú
- Neuropediatric Unit, Hospital Virgen de la Salud, Toledo, Spain
| | | | | | | | | | - José M Serratosa
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain.
| |
Collapse
|
34
|
Association of type IV spinal muscular atrophy (SMA) with myoclonic epilepsy within a single family. Int Arch Med 2014; 7:42. [PMID: 25278999 PMCID: PMC4182784 DOI: 10.1186/1755-7682-7-42] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/22/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spinal muscular atrophies (SMAs) are a group of disorders characterized by degeneration of the anterior horn cells in the spinal cord and motor nuclei in the lower brainstem. It is transmitted by autosomal recessive inheritance and most of these conditions are linked to SMN gene. Even if the clinical picture is mainly dominated by the diffuse muscular atrophy, some patients can also show atypical clinical features such as myoclonic epilepsy ("SMA plus"), which may be related to other genes. In particular, the association of SMA and progressive myoclonic epilepsy (PME) has been previously described. CASE PRESENTATION We present a case of two brothers with late onset SMA associated with a unique form of non progressive myoclonic epilepsy without cognitive impairment or ataxia. They had identical clinical and electrophysiological features. CONCLUSIONS The association of SMA with myoclonic epilepsy may constitute a separate and genetically independent syndrome with unique clinical and electrophysiological findings. Collection of similar cases with genetic studies is needed to define the phenotype clearly and to identify new genes and molecular pathogenetic mechanisms involved in this condition.
Collapse
|
35
|
FORGE Canada Consortium: outcomes of a 2-year national rare-disease gene-discovery project. Am J Hum Genet 2014; 94:809-17. [PMID: 24906018 DOI: 10.1016/j.ajhg.2014.05.003] [Citation(s) in RCA: 188] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Indexed: 01/08/2023] Open
Abstract
Inherited monogenic disease has an enormous impact on the well-being of children and their families. Over half of the children living with one of these conditions are without a molecular diagnosis because of the rarity of the disease, the marked clinical heterogeneity, and the reality that there are thousands of rare diseases for which causative mutations have yet to be identified. It is in this context that in 2010 a Canadian consortium was formed to rapidly identify mutations causing a wide spectrum of pediatric-onset rare diseases by using whole-exome sequencing. The FORGE (Finding of Rare Disease Genes) Canada Consortium brought together clinicians and scientists from 21 genetics centers and three science and technology innovation centers from across Canada. From nation-wide requests for proposals, 264 disorders were selected for study from the 371 submitted; disease-causing variants (including in 67 genes not previously associated with human disease; 41 of these have been genetically or functionally validated, and 26 are currently under study) were identified for 146 disorders over a 2-year period. Here, we present our experience with four strategies employed for gene discovery and discuss FORGE's impact in a number of realms, from clinical diagnostics to the broadening of the phenotypic spectrum of many diseases to the biological insight gained into both disease states and normal human development. Lastly, on the basis of this experience, we discuss the way forward for rare-disease genetic discovery both in Canada and internationally.
Collapse
|