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Lourenço CM, Sallum JMF, Pereira AM, Girotto PN, Kok F, Vilela DRF, Barron E, Pessoa A, Oliveira BMD. A needle in a haystack? The impact of a targeted epilepsy gene panel in the identification of a treatable but rapidly progressive metabolic epilepsy: CLN2 disease. ARQUIVOS DE NEURO-PSIQUIATRIA 2024; 82:1-8. [PMID: 38763144 PMCID: PMC11102811 DOI: 10.1055/s-0044-1786854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 03/30/2024] [Indexed: 05/21/2024]
Abstract
BACKGROUND Neuronal ceroid lipofuscinoses (NCL) are a group of autosomal recessive, inherited, lysosomal, and neurodegenerative diseases that causes progressive dementia, seizures, movement disorders, language delay/regression, progressive visual failure, and early death. Neuronal ceroid lipofuscinosis type 2 (CLN2), caused by biallelic pathogenic variants of the TPP1 gene, is the only NCL with an approved targeted therapy. The laboratory diagnosis of CLN2 is established through highly specific tests, leading to diagnostic delays and eventually hampering the provision of specific treatment for patients with CLN2. Epilepsy is a common and clinically-identifiable feature among NCLs, and seizure onset is the main driver for families to seek medical care. OBJECTIVE To evaluate the results of the Latin America Epilepsy and Genetics Program, an epilepsy gene panel, as a comprehensive tool for the investigation of CLN2 among other genetic causes of epilepsy. METHODS A total of 1,284 patients with epilepsy without a specific cause who had at least 1 symptom associated with CLN2 were screened for variants in 160 genes associated with epilepsy or metabolic disorders presenting with epilepsy through an epilepsy gene panel. RESULTS Variants of the TPP1 gene were identified in 25 individuals (1.9%), 21 of them with 2 variants. The 2 most frequently reported variants were p.Arg208* and p.Asp276Val, and 2 novel variants were detected in the present study: p.Leu308Pro and c.89 + 3G > C Intron 2. CONCLUSION The results suggest that these genetic panels can be very useful tools to confirm or exclude CLN2 diagnosis and, if confirmed, provide disease-specific treatment for the patients.
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Affiliation(s)
| | - Juliana Maria Ferraz Sallum
- Universidade Federal de São Paulo, Escola Paulista de Medicina, Departamento de Oftalmologia e Ciências Visuais, São Paulo SP, Brazil.
| | | | | | - Fernando Kok
- Mendelics Análise Genômica, São Paulo SP, Brazil.
| | | | - Erika Barron
- BioMarin Brasil Farmacêutica Ltda., São Paulo SP, Brazil.
| | - André Pessoa
- Hospital Albert Sabin, Fortaleza CE, Brazil.
- Universidade Estadual do Ceará, Fortaleza CE, Brazil.
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Sivananthan S, Lee L, Anderson G, Csanyi B, Williams R, Gissen P. Buffy Coat Score as a Biomarker of Treatment Response in Neuronal Ceroid Lipofuscinosis Type 2. Brain Sci 2023; 13:209. [PMID: 36831752 PMCID: PMC9954623 DOI: 10.3390/brainsci13020209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/19/2023] [Accepted: 01/22/2023] [Indexed: 01/28/2023] Open
Abstract
The introduction of intracerebroventricular (ICV) enzyme replacement therapy (ERT) for treatment of neuronal ceroid lipofuscinosis type 2 (CLN2) disease has produced dramatic improvements in disease management. However, assessments of therapeutic effect for ICV ERT are limited to clinical observational measures, namely the CLN2 Clinical Rating Scale, a subjective measure of motor and language performance. There is a need for an objective biomarker to enable assessments of disease progression and response to treatment. To address this, we investigated whether the proportion of cells with abnormal storage inclusions on electron microscopic examination of peripheral blood buffy coats could act as a biomarker of disease activity in CLN2 disease. We conducted a prospective longitudinal analysis of six patients receiving ICV ERT. We demonstrated a substantial and continuing reduction in the proportion of abnormal cells over the course of treatment, whereas symptomatic scores revealed little or no change over time. Here, we proposed the use of the proportion of cells with abnormal storage as a biomarker of response to therapy in CLN2. In the future, as more tissue-specific biomarkers are developed, the buffy coats may form part of a panel of biomarkers in order to give a more holistic view of a complex disease.
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Affiliation(s)
- Siyamini Sivananthan
- Department of Inherited Metabolic Diseases, Great Ormond Street Hospital, London WC1N 1EH, UK
| | - Laura Lee
- Department of Inherited Metabolic Diseases, Great Ormond Street Hospital, London WC1N 1EH, UK
| | - Glenn Anderson
- Department of Inherited Metabolic Diseases, Great Ormond Street Hospital, London WC1N 1EH, UK
- Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Barbara Csanyi
- Department of Inherited Metabolic Diseases, Great Ormond Street Hospital, London WC1N 1EH, UK
| | - Ruth Williams
- Department of Children’s Neurosciences, Evelina London Children’s Hospital, London SE1 7EH, UK
| | - Paul Gissen
- Department of Inherited Metabolic Diseases, Great Ormond Street Hospital, London WC1N 1EH, UK
- Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
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Ho ML, Wirrell EC, Petropoulou K, Sakonju A, Chu D, Seratti G, Palasis S. Role of Electroencephalogram (EEG) and Magnetic Resonance Imaging (MRI) Findings in Early Recognition and Diagnosis of Neuronal Ceroid Lipofuscinosis Type 2 Disease. J Child Neurol 2022; 37:984-991. [PMID: 36184928 DOI: 10.1177/08830738221128773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Neuronal ceroid lipofuscinosis type 2 (CLN2) disease is a very rare neurodegenerative lysosomal storage disorder. Progression is rapid and irreversible, making early diagnosis crucial for timely treatment. A group of pediatric neurologists and neuroradiologists with expertise in CLN2 convened to discuss early electroencephalogram (EEG) and magnetic resonance imaging (MRI) findings in CLN2 diagnosis. Of 18 CLN2 cases, 16 (88.9%) had background slowing and 16 (88.9%) had epileptiform discharges on initial EEG. Seven of 17 (41.2%) patients who received intermittent low-frequency photic stimulation had a photoparoxysmal response. Initial MRIs showed subtle cerebellar (n = 14, 77.8%) or cerebral (n = 9, 50.0%) atrophy, white matter abnormalities (n = 11, 61.1%), and basal ganglia T2 hypointensity (n = 6, 33.3%), which became more apparent on follow-up MRI. The recognition of even subtle cerebellar atrophy and white matter signal changes in children aged 2-5 years who present with language delay, new-onset seizures, and an EEG with epileptiform discharges and background slowing should prompt investigation for CLN2. Because these early signs are not unique to CLN2, genetic testing is essential early in the diagnostic journey.
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Affiliation(s)
- Mai-Lan Ho
- Nationwide Children's Hospital, Columbus, OH, USA
| | | | | | - Ai Sakonju
- 12302SUNY Upstate Medical University, Syracuse, NY, USA
| | - Dorna Chu
- 10926BioMarin Pharmaceutical Inc, Novato, CA, USA
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Rodrigues D, de Castro MJ, Crujeiras P, Duat-Rodriguez A, Marco AV, Del Toro M, Couce ML, Colón C. The LINCE Project: A Pathway for Diagnosing NCL2 Disease. Front Pediatr 2022; 10:876688. [PMID: 35425725 PMCID: PMC9002010 DOI: 10.3389/fped.2022.876688] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/07/2022] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION Neuronal Ceroid Lipofuscinosis (NCL) comprises a clinically and genetically heterogeneous group of 13 neurodegenerative lysosomal storage disorders. Neuronal Ceroid lipofuscinosis type 2 disease (NCL2), caused by the deficient lysosomal enzyme tripeptidyl peptidase 1 (TPP1), is the only one with an approved enzyme replacement treatment (ERT). Early initiation of ERT appears to modify significantly the natural history of the disease. We aimed to shorten the time to diagnosis of NCL2. METHODS In March 2017, we started per first time in Spain a selective screening program, the LINCE project, in pediatric patients with clinical symptoms compatible with NCL2 disease. The program covered the whole country. We distributed kits to pediatricians with the necessary material to assess patients. All samples in this study were received within one week of collection. Enzymatic activity determined on dried blood spots was the main method used to screen for TPP1 and palmitoyl protein thioesterase 1 (PPT1) for the differential diagnosis with neuronal ceroid lipofuscinosis type 1 (NCL1). RESULTS Over a period of three years, we received 71 samples. The analysis was minimally invasive, relatively cheap and fast-executing. Three cases identified as a direct result of the selective screening strategy were confirmed by genetic study of NCL2 disease with a median age of 4.5 years. Our screening method has a specificity of 100%, and, with the absence to date of false negatives. We did not detect any NCL1-positive cases. CONCLUSIONS LINCE proved to be a simple, useful, and reliable tool for the diagnosis of NCL2, enabling clinicians to diagnose NCL2 faster. The presence of NCL2-positive cases in our population and availability of treatment may facilitate the inclusion of NCL2 in neonatal screening programs for early diagnosis.
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Affiliation(s)
- Daniel Rodrigues
- Congenital Metabolic Diseases Unit, Department of Neonatology, University Clinical Hospital of Santiago de Compostela, Instituto de Investigación Sanitaria de Santiago (IDIS), European Reference Network for Hereditary Metabolic Disorders (MetabERN), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Santiago de Compostela, Spain.,Department of Pediatrics, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Maria José de Castro
- Congenital Metabolic Diseases Unit, Department of Neonatology, University Clinical Hospital of Santiago de Compostela, Instituto de Investigación Sanitaria de Santiago (IDIS), European Reference Network for Hereditary Metabolic Disorders (MetabERN), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Santiago de Compostela, Spain
| | - Pablo Crujeiras
- Congenital Metabolic Diseases Unit, Department of Neonatology, University Clinical Hospital of Santiago de Compostela, Instituto de Investigación Sanitaria de Santiago (IDIS), European Reference Network for Hereditary Metabolic Disorders (MetabERN), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Santiago de Compostela, Spain.,Department of Pediatrics, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Anna Duat-Rodriguez
- Department of Neuropediatrics, Niño Jesús Children's Hospital, Madrid, Spain
| | - Ana Victoria Marco
- Genomics Unit, La Fe University and Polytechnic Hospital, Valencia, Spain
| | - Mireia Del Toro
- Pediatric Neurology Unit, Vall D'Hebron University Hospital, Barcelona, Spain
| | - María L Couce
- Congenital Metabolic Diseases Unit, Department of Neonatology, University Clinical Hospital of Santiago de Compostela, Instituto de Investigación Sanitaria de Santiago (IDIS), European Reference Network for Hereditary Metabolic Disorders (MetabERN), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Santiago de Compostela, Spain.,Department of Pediatrics, Faculty of Medicine, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Cristóbal Colón
- Congenital Metabolic Diseases Unit, Department of Neonatology, University Clinical Hospital of Santiago de Compostela, Instituto de Investigación Sanitaria de Santiago (IDIS), European Reference Network for Hereditary Metabolic Disorders (MetabERN), Centro de Investigación Biomédica en Red Enfermedades Raras (CIBERER), Santiago de Compostela, Spain
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