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Mahdieh N, Heidari M, Rezaei Z, Tavasoli AR, Hosseinpour S, Rasulinejad M, Dehnavi AZ, Ghahvechi Akbari M, Badv RS, Vafaei E, Mohebbi A, Mohammadi P, Hosseiny SMM, Azizimalamiri R, Nikkhah A, Pourbakhtyaran E, Rohani M, Khanbanha N, Nikbakht S, Movahedinia M, Karimi P, Ghabeli H, Hosseini SA, Rashidi FS, Garshasbi M, Kashani MR, Ghiasvand NM, Zuchner S, Synofzik M, Ashrafi MR. The genetic basis of early-onset hereditary ataxia in Iran: results of a national registry of a heterogeneous population. Hum Genomics 2024; 18:35. [PMID: 38570878 PMCID: PMC10988936 DOI: 10.1186/s40246-024-00598-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 03/14/2024] [Indexed: 04/05/2024] Open
Abstract
BACKGROUND To investigate the genetics of early-onset progressive cerebellar ataxia in Iran, we conducted a study at the Children's Medical Center (CMC), the primary referral center for pediatric disorders in the country, over a three-year period from 2019 to 2022. In this report, we provide the initial findings from the national registry. METHODS We selected all early-onset patients with an autosomal recessive mode of inheritance to assess their phenotype, paraclinical tests, and genotypes. The clinical data encompassed clinical features, the Scale for the Assessment and Rating of Ataxia (SARA) scores, Magnetic Resonance Imaging (MRI) results, Electrodiagnostic exams (EDX), and biomarker features. Our genetic investigations included single-gene testing, Whole Exome Sequencing (WES), and Whole Genome Sequencing (WGS). RESULTS Our study enrolled 162 patients from various geographic regions of our country. Among our subpopulations, we identified known and novel pathogenic variants in 42 genes in 97 families. The overall genetic diagnostic rate was 59.9%. Notably, we observed PLA2G6, ATM, SACS, and SCA variants in 19, 14, 12, and 10 families, respectively. Remarkably, more than 59% of the cases were attributed to pathogenic variants in these genes. CONCLUSIONS Iran, being at the crossroad of the Middle East, exhibits a highly diverse genetic etiology for autosomal recessive hereditary ataxia. In light of this heterogeneity, the development of preventive strategies and targeted molecular therapeutics becomes crucial. A national guideline for the diagnosis and management of patients with these conditions could significantly aid in advancing healthcare approaches and improving patient outcomes.
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Affiliation(s)
- Nejat Mahdieh
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Institute, Iran University of Medical Sciences, Tehran, Iran
| | - Morteza Heidari
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Zahra Rezaei
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Tavasoli
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Pediatric Headache Program, Barrow Neurological Institute, Phoenix Children's Hospital, Phoenix, AZ, USA
| | - Sareh Hosseinpour
- Department of Pediatrics, Division of Paediatric Neurology, Vali-E-Asr Hospital, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Rasulinejad
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Zare Dehnavi
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Masoud Ghahvechi Akbari
- Physical Medicine and Rehabilitation Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Elahe Vafaei
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Mohebbi
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Pouria Mohammadi
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Seyyed Mohammad Mahdi Hosseiny
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Azizimalamiri
- Division of Pediatric Neurology, Department of Pediatrics, Golestan Medical, Educational and Research Center, Ahvaz Jundishapour University of Medical Sciences, Ahvaz, Iran
| | - Ali Nikkhah
- Department of Pediatrics, Division of Paediatric Neurology, Vali-E-Asr Hospital, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pediatrics, Division of Paediatric Neurology, Mofid Children's Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Elham Pourbakhtyaran
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Rohani
- Department of Neurology, School of Medicine, Hazrat Rasool-E Akram General Hospital, Iran University of Medical Sciences, Tehran, Iran
| | - Narges Khanbanha
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Sedigheh Nikbakht
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mojtaba Movahedinia
- Children Growth Disorders Research Center, Department of Pediatric, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Parviz Karimi
- Department of Pediatric Diseases, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Homa Ghabeli
- Department of Pediatrics, School of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Seyed Ahmad Hosseini
- Department of Pediatrics, Taleghani Children's Hospital, Golestan University of Medical Sciences, Gorgan, Iran
| | - Fatemeh Sadat Rashidi
- Neuroscience Research Center, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | | | - Noor M Ghiasvand
- Department of Biology, Grand Valley State University, Allendale, MI, 49401, USA
| | - Stephan Zuchner
- Department of Human Genetics and John P. Hussman Institute for Human Genomics, Dr. John T. Macdonald Foundation, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Germany
- Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Mahmoud Reza Ashrafi
- Pediatric Neurology Division, Pediatrics Center of Excellence, Ataxia Clinic, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Pediatrics, Division of Paediatric Neurology, Growth and Development Research Center, Pediatrics Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.
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Jeridi C, Rachdi A, Nabli F, Saied Z, Zouari R, Ben Mohamed D, Ben Said M, Masmoudi S, Ben Sassi S, Amouri R. Genetic heterogeneity within a consanguineous family involving TTPA and SETX genes. J Neurogenet 2023; 37:124-130. [PMID: 38109176 DOI: 10.1080/01677063.2023.2281916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 11/03/2023] [Indexed: 12/19/2023]
Abstract
Autosomal recessive cerebellar ataxias (ARCA) constitute a highly heterogeneous group of progressive neurodegenerative disorders that typically occur prior to adulthood. Despite some clinical resemblance between these disorders, different genes are involved. We report in this study four Tunisian patients belonging to the same large consanguineous family, sharing autosomal recessive cerebellar ataxia phenotypes but with clinical, biological, electrophysiological, and radiological differences leading to the diagnosis of two distinct ARCA caused by two distinct gene defects. Two of our patients presented ataxia with the vitamin E deficiency (AVED) phenotype, and the other two presented ataxia with oculo-motor apraxia 2 (AOA2). Genetic testing confirmed the clinical diagnosis by the detection of a frameshift c.744delA pathogenic variant in the TTPA gene, which is the most frequent in Tunisia, and a new variant c.1075dupT in the SETX gene. In Tunisia, data suggest that genetic disorders are common. The combined effects of the founder effect and inbreeding, added to genetic drift, may increase the frequency of detrimental rare disorders. The genetic heterogeneity observed in this family highlights the difficulty of genetic counseling in an inbred population. The examination and genetic testing of all affected patients, not just the index patient, is essential to not miss a treatable ataxia such as AVED, as in the case of this family.
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Affiliation(s)
- Cyrine Jeridi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Amine Rachdi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Fatma Nabli
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Zacharia Saied
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Rania Zouari
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Dina Ben Mohamed
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Mariem Ben Said
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratoire Procédés de Criblage Moléculaire et Cellulaire, Centre de Biotechnologie de Sfax, Université de Sfax, Sfax, Tunisia
| | - Samia Ben Sassi
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
| | - Rim Amouri
- Molecular Neurobiology and Neuropathology Department, National Institute Mongi Ben Hamida of Neurology, Tunisia
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Chen S, Du J, Jiang H, Zhao W, Wang N, Ying A, Li J, Chen S, Shen B, Zhou Y. Ataxia with oculomotor apraxia type 2 caused by a novel homozygous mutation in SETX gene, and literature review. Front Mol Neurosci 2022; 15:1019974. [DOI: 10.3389/fnmol.2022.1019974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 09/26/2022] [Indexed: 11/11/2022] Open
Abstract
ObjectivesAutosomal recessive inherited ataxia with oculomotor apraxia type 2 (AOA2), caused by SETX gene mutations, is characterized by early-onset, progressive cerebellar ataxia, peripheral neuropathy, oculomotor apraxia and elevated serum α-fetoprotein (AFP). This study aimed to expand and summarize the clinical and genetic characteristics of SETX variants related to AOA2.MethodsThe biochemical parameters, electromyogram and radiological findings of the patient were evaluated. Whole-exome sequencing (WES) was performed on the patient using next-generation sequencing (NGS), the variants were confirmed by Sanger sequencing and the pathogenicity of the variants was classified according to the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines. We reviewed 57 studies of AOA2 patients with SETX mutations and collected clinical and genetic information.ResultsThe patient was a 40-year-old Chinese woman who primarily presented with numbness and weakness of the lower limbs in her teenage years. She had elevated AFP, increased serum follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and decreased anti-Müllerian hormone (AMH) levels. We identified a novel homozygous missense mutation of the SETX gene, c.7118 C>T (p. Thr2373Ile), in the patient via Whole-exome and Sanger sequencing. The variant was located in the DNA/RNA helicase domain and is highly conserved. The protein prediction analysis verified the SETX variant as a damaging alteration and ACMG/AMP guidelines classified it as likely pathogenic. Through a literature review, we identified 229 AOA2 cases with SETX variants, and among the variants, 156 SETX variants were exonic. We found that 107 (46.7%) patients were European, 50 (21.8%) were African and 48 (21.0%) were Asian. Among the Asian patients, five from two families were Mainland Chinese. The main clinical features were cerebellar ataxia (100%), peripheral neuropathy (94.6%), cerebellar atrophy (95.3%) and elevated AFP concentration (92.0%). Most reported SETX mutations in AOA2 patients were missense, frameshift and nonsense mutations.ConclusionWe discovered a novel homozygous variant of the SETX gene as a cause of AOA2 in the current patient and expanded the genotypic spectrum of AOA2. Moreover, the clinical features of AOA2 and genetic findings in SETX were assessed in reported cohorts and are summarized in the present study.
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Discovery of Therapeutics Targeting Oxidative Stress in Autosomal Recessive Cerebellar Ataxia: A Systematic Review. Pharmaceuticals (Basel) 2022; 15:ph15060764. [PMID: 35745683 PMCID: PMC9228961 DOI: 10.3390/ph15060764] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/05/2022] [Accepted: 06/14/2022] [Indexed: 01/05/2023] Open
Abstract
Autosomal recessive cerebellar ataxias (ARCAs) are a heterogeneous group of rare neurodegenerative inherited disorders. The resulting motor incoordination and progressive functional disabilities lead to reduced lifespan. There is currently no cure for ARCAs, likely attributed to the lack of understanding of the multifaceted roles of antioxidant defense and the underlying mechanisms. This systematic review aims to evaluate the extant literature on the current developments of therapeutic strategies that target oxidative stress for the management of ARCAs. We searched PubMed, Web of Science, and Science Direct Scopus for relevant peer-reviewed articles published from 1 January 2016 onwards. A total of 28 preclinical studies fulfilled the eligibility criteria for inclusion in this systematic review. We first evaluated the altered cellular processes, abnormal signaling cascades, and disrupted protein quality control underlying the pathogenesis of ARCA. We then examined the current potential therapeutic strategies for ARCAs, including aromatic, organic and pharmacological compounds, gene therapy, natural products, and nanotechnology, as well as their associated antioxidant pathways and modes of action. We then discussed their potential as antioxidant therapeutics for ARCAs, with the long-term view toward their possible translation to clinical practice. In conclusion, our current understanding is that these antioxidant therapies show promise in improving or halting the progression of ARCAs. Tailoring the therapies to specific disease stages could greatly facilitate the management of ARCAs.
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A Novel SETX Mutation in a Taiwanese Patient with Autosomal Recessive Cerebellar Ataxia Detected by Targeted Next-Generation Sequencing, and a Literature Review. Brain Sci 2022; 12:brainsci12020173. [PMID: 35203940 PMCID: PMC8869917 DOI: 10.3390/brainsci12020173] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/04/2022] Open
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2), also known as autosomal recessive spinocerebellar ataxia with axonal neuropathy-2 (SCAN2) (OMIM #606002), is a neurodegenerative disorder characterized by early-onset progressive cerebellar ataxia, polyneuropathy, and elevated levels of alpha-fetoprotein. It is caused by mutations in the SETX (OMIM #608465) gene. The prevalence of this disease is widely varied, from non-existent up to 1/150,000, depending on the region. Until now, no cases of AOA2/SCAN2 have been reported in Taiwan. Methods: Next-generation sequencing was used to detect disease-causing mutations of SETX in a Taiwanese patient presenting with autosomal recessive cerebellar ataxia, polyneuropathy, and elevated alpha-fetoprotein. The candidate mutations were further confirmed by polymerase chain reaction (PCR) and Sanger sequencing. Results: A compound heterozygous mutation of SETX c.6859C > T (p.R2287X) and c.7034-7036del was identified. The c.6859C > T (p.R2287X) has been previously found in a Saudi Arabia family, whereas c.7034-7036del is a novel mutation. Both mutations were predicted by bioinformatics programs to be likely pathogenic (having a damaging effect). We also reviewed the literature to address the reported clinical features of AOA2 from different populations. Conclusions: To our knowledge, we are the first to report a Taiwanese patient with AOA2/SCAN2, a result obtained by utilizing next-generation sequencing. The literature review shows that ataxia, polyneuropathy, and elevated AFP are common features and ocular motor apraxia (OMA) is a variable sign of AOA2 from different populations. OMA is rare and saccadic ocular pursuit and nystagmus are common in East Asian AOA2.
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Dragašević-Mišković N, Stanković I, Milovanović A, Kostić VS. Autosomal recessive adult onset ataxia. J Neurol 2021; 269:504-533. [PMID: 34499204 DOI: 10.1007/s00415-021-10763-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 11/24/2022]
Abstract
Autosomal recessive ataxias (ARCA) represent a complex group of diseases ranging from primary ataxias to rare and complex metabolic disorders in which ataxia is a part of the clinical picture. Small number of ARCA manifest exclusively in adulthood, while majority of typical childhood onset ARCA may also start later with atypical clinical presentation. We have systematically searched the literature for ARCA with adult onset, both in the group of primary ataxias including those that are less frequently described in isolated or in a small number of families, and also in the group of complex and metabolic diseases in which ataxia is only part of the clinical picture. We propose an algorithm that could be used when encountering a patient with adult onset sporadic or recessive ataxia in whom the acquired causes are excluded. ARCA are frequently neglected in the differential diagnosis of adult-onset ataxias. Rising awareness of their clinical significance is important, not only because some of these disorders may be potentially treatable, but also for prognostic implications and inclusion of patients to future clinical trials with disease modifying agents.
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Affiliation(s)
- Nataša Dragašević-Mišković
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia.
| | - Iva Stanković
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
| | - Andona Milovanović
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
| | - Vladimir S Kostić
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Dr Subotića 6, 11000, Belgrade, Serbia
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Kinkar JS, Jameel PZ, Kumawat BL, Kalbhor P. Heterozygous deletion in exon 6 of STEX gene causing ataxia with oculomotor apraxia type 2 (AOA-2) with ovarian failure. BMJ Case Rep 2021; 14:14/6/e241767. [PMID: 34193451 DOI: 10.1136/bcr-2021-241767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2), recently renamed as ATX-SETX, is an autosomal recessive, progressive neurodegenerative disorder belonging to inherited cerebellar ataxias. The pathogenic variants of the SETX gene have been implicated in ATX-SETX. We report the case of a 21-year-old woman presenting with ataxia, oculomotor apraxia and dystonia. She had elevated serum α-fetoprotein (AFP), follicle stimulating hormone (FSH) and luteinising hormone (LH) levels and moderate cerebellar atrophy. On further evaluation, she was found to have premature ovarian failure as well. Multiplex ligation-dependent probe amplification detected a heterozygous deletion in exon 6 of the SETX gene. A combination of cerebellar ataxia, oculomotor apraxia with elevated AFP and cerebellar atrophy are highly suggestive of ATX-SETX. In rare instances, it may be associated with premature ovarian failure with elevated FSH and LH levels, necessitating hormonal survey and fertility evaluation in all patients with ATX-SETX.
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Affiliation(s)
- Jiwan Shriram Kinkar
- Department of Neurology, Jawaharlal Nehru Medical College, Wardha, Maharashtra, India
| | - Patel Zeeshan Jameel
- Department of Paediatrics, Jawaharlal Nehru Medical College, Wardha, Maharashtra, India
| | - Banshi Lal Kumawat
- Department of Neurology, Sawai Man Singh Medical College and Hospital, Jaipur, Rajasthan, India
| | - Priyanka Kalbhor
- Department of Microbiology, Government Medical College and Hospital, Nagpur, Maharashtra, India
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Genetic and Epidemiological Study of Adult Ataxia and Spastic Paraplegia in Eastern Quebec. Can J Neurol Sci 2021; 48:655-665. [PMID: 33397523 DOI: 10.1017/cjn.2020.277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To estimate the minimum prevalence of adult hereditary ataxias (HA) and spastic paraplegias (HSP) in Eastern Quebec and to evaluate the proportion of associated mutations in identified genes. METHODS We conducted a descriptive cross-sectional study of patients who met clinical criteria for the diagnosis of HA (n = 241) and HSP (n = 115) in the East of the Quebec province between January 2007 and July 2019. The primary outcome was the prevalence per 100,000 persons with a 95% confidence interval (CI). The secondary outcome was the frequency of mutations identified by targeted next-generation sequencing (NGS) approach. Minimum carrier frequency for identified variants was calculated based on allele frequency values and the Hardy-Weinberg (HW) equation. RESULTS The minimum prevalence of HA in Eastern Quebec was estimated at 6.47/100 000 [95% CI; 6.44-6.51]; divided into 3.73/100 000 for autosomal recessive (AR) ataxias and 2.67/100 000 for autosomal dominant (AD) ataxias. The minimum prevalence of HSP was 4.17/100 000 [95% CI; 4.14-4.2]; with 2.05/100 000 for AD-HSP and 2.12/100 000 for AR-HSP. In total, 52.4% of patients had a confirmed genetic diagnosis. AR cerebellar ataxia type 1 (2.67/100 000) and AD spastic paraplegia SPG4 (1.18/100 000) were the most prevalent disorders identified. Mutations were identified in 23 genes and molecular alterations in 7 trinucleotides repeats expansion; the most common mutations were c.15705-12 A > G in SYNE1 and c.1529C > T (p.A510V) in SPG7. CONCLUSIONS We described the minimum prevalence of genetically defined adult HA and HSP in Eastern Quebec. This study provides a framework for international comparisons and service planning.
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Baizabal-Carvallo JF, Cardoso F. Chorea in children: etiology, diagnostic approach and management. J Neural Transm (Vienna) 2020; 127:1323-1342. [DOI: 10.1007/s00702-020-02238-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/01/2020] [Indexed: 01/07/2023]
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10
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Gana S, Valente EM. Movement Disorders in Genetic Pediatric Ataxias. Mov Disord Clin Pract 2020; 7:383-393. [PMID: 32373654 DOI: 10.1002/mdc3.12937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/24/2020] [Accepted: 03/08/2020] [Indexed: 11/06/2022] Open
Abstract
Background Genetic pediatric ataxias are heterogeneous rare disorders, mainly inherited as autosomal-recessive traits. Most forms are progressive and lack effective treatment, with relevant socioeconomical impact. Albeit ataxia represents the main clinical feature, the phenotype can be more complex, with additional neurological and nonneurological signs being described in several forms. Methods and Results In this review, we provide an overview of the occurrence and spectrum of movement disorders in the most relevant forms of childhood-onset genetic ataxias. All types of hypokinetic and hyperkinetic movement disorders of variable severity have been reported. Movement disorders occasionally represent the symptom of onset, predating ataxia even of a few years and therefore challenging an early diagnosis. Their pathogenesis still remains poorly defined, as it is not yet clear whether movement disorders may directly relate to the cerebellar pathology or result from an extracerebellar dysfunction, including the basal ganglia. Conclusion Recognition of the complete movement disorder phenotype in genetic pediatric ataxias has important implications for diagnosis, management, and genetic counseling.
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Affiliation(s)
| | - Enza Maria Valente
- IRCCS Mondino Foundation Pavia Italy.,Department of Molecular Medicine University of Pavia Pavia Italy
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Paucar M, Taylor AMR, Hadjivassiliou M, Fogel BL, Svenningsson P. Progressive Ataxia with Elevated Alpha-Fetoprotein: Diagnostic Issues and Review of the Literature. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:tre-09-708. [PMID: 31656689 PMCID: PMC6790008 DOI: 10.7916/tohm.v0.708] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/13/2019] [Indexed: 12/23/2022]
Abstract
Background Ataxias represent a challenging group of disorders due to significant clinical overlap. Here, we present a patient with early-onset progressive ataxia, polyneuropathy and discuss how elevation of alpha fetoprotein (AFP) narrows the differential diagnosis. Case report Ataxia, polyneuropathy, and mild elevation of AFP are features compatible with ataxia with oculomotor apraxia type 2 (AOA2) but also with ataxia with oculomotor apraxia type 4 (AOA4). A genetic analysis demonstrated biallelic mutations in senataxin (SETX), confirming the diagnosis of AOA2. Discussion Mild elevation of AFP is found in patients with AOA2 and AOA4, and higher levels are commonly seen in ataxia-telangiectasia. AFP is a useful diagnostic tool but not a biomarker for disease progression in AOA2.
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Affiliation(s)
- Martin Paucar
- Department of Neurology, Karolinska University Hospital, Stockholm, SE.,Department of Clinical Neuroscience, Karolinska Institute, Stockholm, SE
| | - Alexander M R Taylor
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | | | - Brent L Fogel
- Department of Neurology, UCLA Program in Neurogenetics, David Geffen School of Medicine, University of California at Los Angeles (UCLA), Los Angeles, CA, USA
| | - Per Svenningsson
- Department of Neurology, Karolinska University Hospital, Stockholm, SE.,Department of Clinical Neuroscience, Karolinska Institute, Stockholm, SE
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Brandsma R, Verschuuren-Bemelmans CC, Amrom D, Barisic N, Baxter P, Bertini E, Blumkin L, Brankovic-Sreckovic V, Brouwer OF, Bürk K, Catsman-Berrevoets CE, Craiu D, de Coo IFM, Gburek J, Kennedy C, de Koning TJ, Kremer HPH, Kumar R, Macaya A, Micalizzi A, Mirabelli-Badenier M, Nemeth A, Nuovo S, Poll-The B, Lerman-Sagie T, Steinlin M, Synofzik M, Tijssen MAJ, Vasco G, Willemsen MAAP, Zanni G, Valente EM, Boltshauser E, Sival DA. A clinical diagnostic algorithm for early onset cerebellar ataxia. Eur J Paediatr Neurol 2019; 23:692-706. [PMID: 31481303 DOI: 10.1016/j.ejpn.2019.08.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 05/25/2019] [Accepted: 08/06/2019] [Indexed: 10/26/2022]
Abstract
Early onset cerebellar Ataxia (EOAc) comprises a large group of rare heterogeneous disorders. Determination of the underlying etiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This may change the diagnostic work-up into a time-consuming, costly and not always rewarding task. In this overview, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society (CACG-EPNS) presents a diagnostic algorithm for EOAc patients. In seven consecutive steps, the algorithm leads the clinician through the diagnostic process, including EOA identification, application of the Inventory of Non-Ataxic Signs (INAS), consideration of the family history, neuro-imaging, laboratory investigations, genetic testing by array CGH and Next Generation Sequencing (NGS). In children with EOAc, this algorithm is intended to contribute to the diagnostic process and to allow uniform data entry in EOAc databases.
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Affiliation(s)
- R Brandsma
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - C C Verschuuren-Bemelmans
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - D Amrom
- Department of Neurology, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Brussels, Belgium; Neurology Unit, Kannerklinik Centre Hospitalier de Luxembourg, Luxembourg, Grand Duchy of Luxembourg
| | - N Barisic
- Department of Pediatrics, Clinical Medical Centre Zagreb, University of Zagreb Medical School, Croatia
| | - P Baxter
- Department of Paediatric Neurology, Sheffield Children's Hospital, UK
| | - E Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - L Blumkin
- Pediatric Neurology Unit, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - V Brankovic-Sreckovic
- Clinic for Child Neurology and Psychiatry, Medical Faculty, University of Belgrade, Belgrade, Serbia
| | - O F Brouwer
- Department of Paediatric Neurology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - K Bürk
- Paracelsus-Elena-Klinik Kassel, University of Marburg, Germany
| | - C E Catsman-Berrevoets
- Department of Pediatric Neurology, Erasmus University Hospital/Sophia Children's Hospital, Rotterdam, the Netherlands
| | - D Craiu
- Carol Davila University of Medicine Bucharest, Department of Clinical Neurosciences, Pediatric Neurology II Discipline, Alexandru Obregia Hospital, Bucharest, Romania
| | - I F M de Coo
- Department of Genetics and Cell Biology, University of Maastricht, Maastricht, the Netherlands
| | - J Gburek
- Centre for Paediatrics and Adolescent Medicine, Hannover Medical School, Hannover, Germany
| | - C Kennedy
- Clinical Neurosciences, Faculty of Medicine, University of Southampton, UK
| | - T J de Koning
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands; Department of Paediatric Neurology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - H P H Kremer
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - R Kumar
- Department of Pediatric Neurology, Alder Hey Children's NHS Foundation Trust, Liverpool, UK
| | - A Macaya
- Grup de Recerca en Neurologia Pediàtrica, Institut de Recerca Vall d'Hebron, Universitat Autònoma de Barcelona, Secció de Neurologia Pediàtrica, Hospital Universitari Vall d'Hebron, 08002, Barcelona, Spain
| | - A Micalizzi
- Laboratory of Medical Genetics, Bambino Gesu Children's Hospital, Rome, Italy
| | - M Mirabelli-Badenier
- DINOGMI Department-University of Genoa/Unit of Child Neuropsychiatry, G. Gaslini Institute, Genoa, Italy
| | - A Nemeth
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom; Oxford Centre for Genomic Medicine, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - S Nuovo
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - B Poll-The
- Department of Pediatric Neurology, Emma Children's Hospital, Academic Medical Centre (AMC), University of Amsterdam, the Netherlands
| | - T Lerman-Sagie
- Pediatric Neurology Unit, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - M Steinlin
- Division of Neuropediatrics, Development and Rehabilitation, University Children's Hospital Bern, Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - M Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany; German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
| | - M A J Tijssen
- Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands
| | - G Vasco
- Division of Neurorehabilitation, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - M A A P Willemsen
- Department of Pediatric Neurology, Radboud University Medical Center/Amalia Children's Hospital, Nijmegen, the Netherlands
| | - G Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesu' Children's Research Hospital, Rome, Italy
| | - E M Valente
- Neurogenetics Unit, IRCCS Santa Lucia Foundation, Rome, Italy; Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - E Boltshauser
- Department of Pediatric Neurology, University Children's Hospital, Zürich, Switzerland
| | - D A Sival
- Department of Paediatric Neurology, Beatrix Children's Hospital, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
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Arias M. Keys to overcoming the challenge of diagnosing autosomal recessive spinocerebellar ataxia. NEUROLOGÍA (ENGLISH EDITION) 2019. [DOI: 10.1016/j.nrleng.2018.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
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14
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Jung I, Kim JS. Abnormal Eye Movements in Parkinsonism and Movement Disorders. J Mov Disord 2019; 12:1-13. [PMID: 30732429 PMCID: PMC6369379 DOI: 10.14802/jmd.18034] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/07/2018] [Accepted: 12/12/2018] [Indexed: 01/10/2023] Open
Abstract
Abnormal eye movements are commonly observed in movement disorders. Ocular motility examination should include bedside evaluation and laboratory recording of ocular misalignment, involuntary eye movements, including nystagmus and saccadic intrusions/oscillations, triggered nystagmus, saccades, smooth pursuit (SP), and the vestibulo-ocular reflex. Patients with Parkinson's disease (PD) mostly show hypometric saccades, especially for the selfpaced saccades, and impaired SP. Early vertical saccadic palsy is characteristic of progressive supranuclear palsy-Richardson's syndrome. Patients with cortico-basal syndrome typically show a delayed onset of saccades. Downbeat and gaze-evoked nystagmus and hypermetric saccades are characteristic ocular motor findings in ataxic disorders due to cerebellar dysfunction. In this review, we discuss various ocular motor findings in movement disorders, including PD and related disorders, ataxic syndromes, and hyperkinetic movement disorders. Systemic evaluation of the ocular motor functions may provide valuable information for early detection and monitoring of movement disorders, despite an overlap in the abnormal eye movements among different movement disorders.
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Affiliation(s)
- Ileok Jung
- Department of Neurology, Korea University College of Medicine, Korea University Ansan Hospital, Ansan, Korea
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul, Korea
- Dizziness Center, Clinical Neuroscience Center, and Department of Neurology, Seoul National University Bundang Hospital, Seongnam, Korea
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15
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Algahtani H, Shirah B, Algahtani R, Naseer MI, Al-Qahtani MH, Abdulkareem AA. Ataxia with ocular apraxia type 2 not responding to 4-aminopyridine: A rare mutation in the SETX gene in a Saudi patient. Intractable Rare Dis Res 2018; 7:275-279. [PMID: 30560021 PMCID: PMC6290838 DOI: 10.5582/irdr.2018.01107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Ataxia with ocular apraxia type 2 is an autosomal recessive disorder caused by a mutation in the senataxin (SETX) gene. The disease is characterized by early onset cerebellar ataxia, cerebellar atrophy, axonal sensorimotor neuropathy, oculomotor apraxia, and increased levels of α-fetoprotein. Reported here is a rare homozygous frameshift deletion c.5308_5311del, p.(Glu1770Ilefs*15) in the SETX gene in a Saudi family. Ataxia with ocular apraxia type 2 was diagnosed based on the patient's history, an examination, and genetic testing. Genetic testing remains the only definitive method with which to identify the gene responsible. This is the third case report of this rare mutation in the literature. Ataxia with ocular apraxia type 2 continues to be a challenging disease to manage with no therapeutic options available to date. In the current case, the medication 4-aminopyridine was inefficacious in improving walking or balance. Further research is needed to identify potential treatments for this challenging condition.
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Affiliation(s)
- Hussein Algahtani
- King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
- Address correspondence to:Dr. Hussein Algahtani, King Abdulaziz Medical City, King Saud bin Abdulaziz University for Health Sciences, Contact No.: 00966556633130. P.O. Box: 12723, Jeddah, Saudi Arabia 21483. E-mail:
| | - Bader Shirah
- King Abdullah International Medical Research Center, King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Raghad Algahtani
- King Saud bin Abdulaziz University for Health Sciences, Jeddah, Saudi Arabia
| | - Muhammad Imran Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammad H. Al-Qahtani
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Saudi Arabia
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16
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A novel SETX gene mutation producing ataxia with oculomotor apraxia type 2. Acta Neurol Belg 2016; 116:405-7. [PMID: 26811093 DOI: 10.1007/s13760-015-0569-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022]
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17
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Keys to overcoming the challenge of diagnosing autosomal recessive spinocerebellar ataxia. Neurologia 2016; 34:248-258. [PMID: 27460185 DOI: 10.1016/j.nrl.2016.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/06/2016] [Accepted: 06/09/2016] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION Autosomal recessive spinocerebellar ataxia refers to a large group of diseases affecting the cerebellum and/or its connections, although they may also involve other regions of the nervous system. These diseases are accompanied by a wide range of systemic manifestations (cardiopathies, endocrinopathies, skeletal deformities, and skin abnormalities). DEVELOPMENT This study reviews current knowledge of the most common forms of autosomal recessive spinocerebellar ataxia in order to provide tips that may facilitate diagnosis. CONCLUSIONS A thorough assessment of clinical phenotype (pure cerebellar or cerebellar-plus syndrome, with or without systemic manifestations), laboratory tests (vitamin E, acanthocytosis, albumin, cholesterol, phytanic acid, lactic acid, creatine kinase, cholestanol, coenzyme Q10, alpha-fetoprotein, copper, ceruloplasmin, chitotriosidase), nerve conduction studies (presence and type of neuropathy), and an magnetic resonance imaging study (presence of cerebellar atrophy, presence and location of signal alterations) may help establish a suspected diagnosis, which should be confirmed by detecting the underlying genetic mutation. A positive genetic test result is necessary to determine prognosis and provide adequate genetic counselling, and will also permit appropriate treatment of some entities (abetalipoproteinaemia, ataxia with vitamin E deficiency, Refsum disease, cerebrotendinous xanthomatosis, Niemann-Pick disease type C, Wilson disease). Without a genetic diagnosis, conducting basic research and therapeutic trials will not be possible.
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18
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Pearson TS. More Than Ataxia: Hyperkinetic Movement Disorders in Childhood Autosomal Recessive Ataxia Syndromes. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2016; 6:368. [PMID: 27536460 PMCID: PMC4950223 DOI: 10.7916/d8h70fss] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 04/21/2016] [Indexed: 12/12/2022]
Abstract
Background The autosomal recessive ataxias are a heterogeneous group of disorders that are characterized by complex neurological features in addition to progressive ataxia. Hyperkinetic movement disorders occur in a significant proportion of patients, and may sometimes be the presenting motor symptom. Presentations with involuntary movements rather than ataxia are diagnostically challenging, and are likely under-recognized. Methods A PubMed literature search was performed in October 2015 utilizing pairwise combinations of disease-related terms (autosomal recessive ataxia, ataxia–telangiectasia, ataxia with oculomotor apraxia type 1 (AOA1), ataxia with oculomotor apraxia type 2 (AOA2), Friedreich ataxia, ataxia with vitamin E deficiency), and symptom-related terms (movement disorder, dystonia, chorea, choreoathetosis, myoclonus). Results Involuntary movements occur in the majority of patients with ataxia–telangiectasia and AOA1, and less frequently in patients with AOA2, Friedreich ataxia, and ataxia with vitamin E deficiency. Clinical presentations with an isolated hyperkinetic movement disorder in the absence of ataxia include dystonia or dystonia with myoclonus with predominant upper limb and cervical involvement (ataxia–telangiectasia, ataxia with vitamin E deficiency), and generalized chorea (ataxia with oculomotor apraxia type 1, ataxia-telangiectasia). Discussion An awareness of atypical presentations facilitates early and accurate diagnosis in these challenging cases. Recognition of involuntary movements is important not only for diagnosis, but also because of the potential for effective targeted symptomatic treatment.
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Affiliation(s)
- Toni S Pearson
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
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19
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Hamza W, Ali Pacha L, Hamadouche T, Muller J, Drouot N, Ferrat F, Makri S, Chaouch M, Tazir M, Koenig M, Benhassine T. Molecular and clinical study of a cohort of 110 Algerian patients with autosomal recessive ataxia. BMC MEDICAL GENETICS 2015; 16:36. [PMID: 26068213 PMCID: PMC4630839 DOI: 10.1186/s12881-015-0180-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Accepted: 05/29/2015] [Indexed: 12/12/2022]
Abstract
BACKGROUND Autosomal recessive cerebellar ataxias (ARCA) are a complex group of neurodegenerative disorders with great genetic and phenotypic heterogeneity, over 30 genes/loci have been associated with more than 20 different clinical forms of ARCA. Genetic heterogeneity combined with highly variable clinical expression of the cerebellar symptoms and overlapping features complicate furthermore the etiological diagnosis of ARCA. The determination of the most frequent mutations and corresponding ataxias, as well as particular features specific to a population, are mandatory to facilitate and speed up the diagnosis process, especially when an appropriate treatment is available. METHODS We explored 166 patients (115 families) refered to the neurology units of Algiers central hospitals (Algeria) with a cerebellar ataxia phenotype segregating as an autosomal recessive pattern of inheritance. Genomic DNA was extracted from peripheral blood samples and mutational screening was performed by PCR and direct sequencing or by targeted genomic capture and massive parallel sequencing of 57 genes associated with inherited cerebellar ataxia phenotypes. RESULTS In this work we report the clinical and molecular results obtained on a large cohort of Algerian patients (110 patients/76 families) with genetically determined autosomal recessive ataxia, representing 9 different types of ARCA and 23 different mutations, including 6 novel ones. The five most common ARCA in this cohort were Friedreich ataxia, ataxia with isolated vitamin E deficiency, ataxia with oculomotor apraxia type 2, autosomal recessive spastic ataxia of Charlevoix-Saguenay and ataxia with oculomotor apraxia type 1. CONCLUSION We report here a large cohort of patients with genetically determined autosomal recessive ataxia and the first study of the genetic context of ARCA in Algeria. This study showed that in Algerian patients, the two most common types of ataxia (Friedreich ataxia and ataxia with isolated vitamin E deficiency) coexist with forms that may be less common or underdiagnosed. To refine the genotype/phenotype correlation in rare and heteregeneous diseases as autosomal recessive ataxias, more extensive epidemiological investigations and reports are necessary as well as more accurate and detailed clinical characterizations. The use of standardized clinical and molecular protocols would thus enable a better knowledge of the different forms of ARCA.
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Affiliation(s)
- Wahiba Hamza
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, USTHB, Alger, Algeria.
| | - Lamia Ali Pacha
- Service de Neurologie, CHU Mustapha Bacha, Alger, Algeria. .,Laboratoire de Neurosciences, Université d'Alger 1, Alger, Algeria.
| | - Tarik Hamadouche
- Laboratoire de Neurosciences, Université d'Alger 1, Alger, Algeria. .,Laboratoire de Biologie Moléculaire, Faculté des Sciences, UMBB, Boumerdes, Algeria.
| | - Jean Muller
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/Université de Strasbourg UMR7104, INSERM U964, Illkirch, France. .,Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.
| | - Nathalie Drouot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/Université de Strasbourg UMR7104, INSERM U964, Illkirch, France.
| | - Farida Ferrat
- Service de Neurologie, CHU Ben Aknoun, Alger, Algeria.
| | - Samira Makri
- Service de Neurologie, EHS Ali Aït Idir, Alger, Algeria.
| | | | - Meriem Tazir
- Service de Neurologie, CHU Mustapha Bacha, Alger, Algeria. .,Laboratoire de Neurosciences, Université d'Alger 1, Alger, Algeria.
| | - Michel Koenig
- Laboratoire de Génétique de Maladies Rares, Institut Universitaire de Recherche Clinique, Université de Montpellier, CHU de Montpellier, Montpellier, France.
| | - Traki Benhassine
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, USTHB, Alger, Algeria.
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20
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Mancini C, Orsi L, Guo Y, Li J, Chen Y, Wang F, Tian L, Liu X, Zhang J, Jiang H, Nmezi BS, Tatsuta T, Giorgio E, Di Gregorio E, Cavalieri S, Pozzi E, Mortara P, Caglio MM, Balducci A, Pinessi L, Langer T, Padiath QS, Hakonarson H, Zhang X, Brusco A. An atypical form of AOA2 with myoclonus associated with mutations in SETX and AFG3L2. BMC MEDICAL GENETICS 2015; 16:16. [PMID: 25927548 PMCID: PMC4422141 DOI: 10.1186/s12881-015-0159-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Accepted: 02/26/2015] [Indexed: 11/10/2022]
Abstract
BACKGROUND Hereditary ataxias are a heterogeneous group of neurodegenerative disorders, where exome sequencing may become an important diagnostic tool to solve clinically or genetically complex cases. METHODS We describe an Italian family in which three sisters were affected by ataxia with postural/intentional myoclonus and involuntary movements at onset, which persisted during the disease. Oculomotor apraxia was absent. Clinical and genetic data did not allow us to exclude autosomal dominant or recessive inheritance and suggest a disease gene. RESULTS Exome sequencing identified a homozygous c.6292C > T (p.Arg2098*) mutation in SETX and a heterozygous c.346G > A (p.Gly116Arg) mutation in AFG3L2 shared by all three affected individuals. A fourth sister (II.7) had subclinical myoclonic jerks at proximal upper limbs and perioral district, confirmed by electrophysiology, and carried the p.Gly116Arg change. Three siblings were healthy. Pathogenicity prediction and a yeast-functional assay suggested p.Gly116Arg impaired m-AAA (ATPases associated with various cellular activities) complex function. CONCLUSIONS Exome sequencing is a powerful tool in identifying disease genes. We identified an atypical form of Ataxia with Oculoapraxia type 2 (AOA2) with myoclonus at onset associated with the c.6292C > T (p.Arg2098*) homozygous mutation. Because the same genotype was described in six cases from a Tunisian family with a typical AOA2 without myoclonus, we speculate this latter feature is associated with a second mutated gene, namely AFG3L2 (p.Gly116Arg variant). We suggest that variant phenotypes may be due to the combined effect of different mutated genes associated to ataxia or related disorders, that will become more apparent as the costs of exome sequencing progressively will reduce, amplifying its diagnostics use, and meanwhile proposing significant challenges in the interpretation of the data.
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Affiliation(s)
- Cecilia Mancini
- Department of Medical Sciences, University of Torino, via Santena 19, 10126, Torino, Italy.
| | - Laura Orsi
- Struttura Complessa Neurologia I, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
| | - Yiran Guo
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | | | | | - Fengxiang Wang
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | - Lifeng Tian
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
| | | | | | - Hui Jiang
- BGI-Shenzhen, Shenzhen, 510803, China. .,Shenzhen Key Laboratory of Genomics, Shenzhen, 518083, China. .,The Guangdong Enterprise Key Laboratory of Human Disease Genomics, BGI-Shenzhen, Shenzhen, 510803, China.
| | - Bruce Shike Nmezi
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
| | - Takashi Tatsuta
- Institute for Genetics, Center for Molecular Medicine (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, 50931, Germany.
| | - Elisa Giorgio
- Department of Medical Sciences, University of Torino, via Santena 19, 10126, Torino, Italy.
| | - Eleonora Di Gregorio
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
| | - Simona Cavalieri
- Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
| | - Elisa Pozzi
- Department of Medical Sciences, University of Torino, via Santena 19, 10126, Torino, Italy.
| | - Paolo Mortara
- Struttura Complessa Neurologia I, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy. .,Department of Neuroscience, University of Torino, Torino, 10126, Italy.
| | - Maria Marcella Caglio
- Department of Neuroscience, University of Torino, Torino, 10126, Italy. .,Division of Neurology III, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
| | - Alessandro Balducci
- Department of Neuroscience, University of Torino, Torino, 10126, Italy. .,Division of Neurology III, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
| | - Lorenzo Pinessi
- Struttura Complessa Neurologia I, Department of Neuroscience and Mental Health, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy. .,Department of Neuroscience, University of Torino, Torino, 10126, Italy.
| | - Thomas Langer
- Institute for Genetics, Center for Molecular Medicine (CMMC), Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, 50931, Germany. .,Max-Planck-Institute for Biology of Aging, Cologne, 50931, Germany.
| | - Quasar S Padiath
- Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, 15261, USA.
| | - Hakon Hakonarson
- Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA. .,Division of Human Genetics, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA. .,Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
| | - Xiuqing Zhang
- BGI-Shenzhen, Shenzhen, 510803, China. .,Shenzhen Key Laboratory of Genomics, Shenzhen, 518083, China. .,The Guangdong Enterprise Key Laboratory of Human Disease Genomics, BGI-Shenzhen, Shenzhen, 510803, China.
| | - Alfredo Brusco
- Department of Medical Sciences, University of Torino, via Santena 19, 10126, Torino, Italy. .,Medical Genetics Unit, Città della Salute e della Scienza University Hospital, Torino, 10126, Italy.
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D'Amico MC, Borrelli I, Zhuzhuni H, D'Amico A, Di Giacomo R, Mancinelli L, di Tommaso V, Di Muzio A, Onofrj M. Holmes-Like Tremor in Ataxia With Oculomotor Apraxia Type 2. Mov Disord Clin Pract 2014; 1:261-262. [DOI: 10.1002/mdc3.12070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 05/12/2014] [Accepted: 05/25/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Maria Chiara D'Amico
- Department of Neuroscience and Imaging; University “G. d'Annunzio” of Chieti-Pescara; Chieti Italy
| | - Iole Borrelli
- Neurology Clinic; “SS. Annunziata” Hospital; Chieti Italy
| | - Holta Zhuzhuni
- Neurology Clinic; “SS. Annunziata” Hospital; Chieti Italy
| | | | | | | | | | | | - Marco Onofrj
- Department of Neuroscience and Imaging; University “G. d'Annunzio” of Chieti-Pescara; Chieti Italy
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DNA repair abnormalities leading to ataxia: shared neurological phenotypes and risk factors. Neurogenetics 2014; 15:217-28. [PMID: 25038946 DOI: 10.1007/s10048-014-0415-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 07/11/2014] [Indexed: 02/06/2023]
Abstract
Since identification of mutations in the ATM gene leading to ataxia-telangiectasia, enormous efforts have been devoted to discovering the roles this protein plays in DNA repair as well as other cellular functions. Even before the identification of ATM mutations, it was clear that other diseases with different genomic loci had very similar neurological symptoms. There has been significant progress in understanding why cancer and immunodeficiency occur in ataxia-telangiectasia even though many details remain to be determined, but the field is no closer to determining why the nervous system requires ATM and other DNA repair genes. Even though rodent disease models have similar DNA repair abnormalities as the human diseases, they have no consistent, robust neuropathological phenotype making it difficult to understand the neurological underpinnings of disease. Therefore, it may be useful to reassess the neurological and neuropathological characteristics of ataxia-telangiectasia in human patients to look for potential commonalities in DNA repair diseases that result in ataxia. In doing so, it is clear that ataxia-telangiectasia and similar diseases share neurological features other than merely ataxia, such as length-dependent motor and sensory neuropathies, and that the neuroanatomical localization for these symptoms is understood. Cells affected in ataxia-telangiectasia and similar diseases are some of the largest single nucleated cells in the body. In addition, a subset of these diseases also has extrapyramidal movements and oculomotor apraxia. These neurological and neuropathological similarities may indicate a common DNA repair related pathogenesis with very large cell size as a critical risk factor.
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Brugger F, Schüpbach M, Koenig M, Müri R, Bohlhalter S, Kaelin-Lang A, Kamm CP, Kägi G. The Clinical Spectrum of Ataxia with Oculomotor Apraxia Type 2. Mov Disord Clin Pract 2014; 1:106-109. [PMID: 30363866 DOI: 10.1002/mdc3.12021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/10/2014] [Accepted: 03/12/2014] [Indexed: 11/07/2022] Open
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is an inherited disorder caused by mutations within both alleles of the senataxin gene. First symptoms are usually recognized before the age of 30. Unlike several other autosomal recessive cerebellar ataxia syndromes, levels of alpha-fetoprotein are nearly always elevated in AOA2 and thus narrowing down the differential diagnosis list. We present 3 video cases illustrating and expanding the clinical spectrum of AOA2, with 1 case bearing a novel mutation with cervical dystonia as the first symptom, the absence of neuropathy, and a disease onset beyond the age of 40. Furthermore, all patients were assessed by oculographic analysis, which revealed distinct patterns of oculomotor abnormalities. The clinical spectrum of AOA2 might be even broader than previously described in larger series. Oculography might be a useful tool to detect subclinical oculomotor apraxia in this disorder.
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Affiliation(s)
- Florian Brugger
- Movement Disorders Center of Eastern Switzerland Department of Neurology Kantonsspital St.Gallen St.Gallen Switzerland
| | - Michael Schüpbach
- Movement Disorders Center Department of Neurology University Hospital Berne University of Berne Berne Switzerland
| | - Michel Koenig
- Laboratoire de Diagnostic Génétique Nouvel Hôpital Civil Strasbourg France
- Institut de Génétique et de Biologie Moléculaire et Cellulaire CNRS/Université de Strasbourg/INSERM Illkirch France
| | - René Müri
- Perception and Eye Movement Laboratory Departments of Neurology and Clinical Research Inselspital, University Hospital Berne Berne Switzerland
| | - Stephan Bohlhalter
- Perception and Eye Movement Laboratory Departments of Neurology and Clinical Research Inselspital, University Hospital Berne Berne Switzerland
- Neurology and Neurorehabilitation Center Department of Internal Medicine Luzerner Kantonsspital Lucerne Switzerland
| | - Alain Kaelin-Lang
- Movement Disorders Center Department of Neurology University Hospital Berne University of Berne Berne Switzerland
| | - Christian P Kamm
- Perception and Eye Movement Laboratory Departments of Neurology and Clinical Research Inselspital, University Hospital Berne Berne Switzerland
| | - Georg Kägi
- Movement Disorders Center of Eastern Switzerland Department of Neurology Kantonsspital St.Gallen St.Gallen Switzerland
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Roda RH, Rinaldi C, Singh R, Schindler AB, Blackstone C. Ataxia with oculomotor apraxia type 2 fibroblasts exhibit increased susceptibility to oxidative DNA damage. J Clin Neurosci 2014; 21:1627-31. [PMID: 24814856 DOI: 10.1016/j.jocn.2013.11.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 11/05/2013] [Accepted: 11/10/2013] [Indexed: 10/25/2022]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive cerebellar ataxia associated with mutations in SETX, which encodes the senataxin protein, a DNA/RNA helicase. We describe the clinical phenotype and molecular characterization of a Colombian AOA2 patient who is compound heterozygous for a c.994 C>T (p.R332W) missense mutation in exon 7 and a c.6848_6851delCAGA (p.T2283KfsX32) frameshift deletion in SETX exon 21. Immunocytochemistry of patient-derived fibroblasts revealed a normal cellular distribution of the senataxin protein, suggesting that these mutations do not lead to loss or mis-localization of the protein, but rather that aberrant function of senataxin underlies the disease pathogenesis. Furthermore, we used the alkaline comet assay to demonstrate that patient-derived fibroblast cells exhibit an increased susceptibility to oxidative DNA damage. This assay provides a novel and additional means to establish pathogenicity of SETX mutations.
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Affiliation(s)
- Ricardo H Roda
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA.
| | - Carlo Rinaldi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Rajat Singh
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Alice B Schindler
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 35, Room 2C-911, 9000 Rockville Pike, Bethesda, MD 20892-3738, USA
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Schieving JH, de Vries M, van Vugt JMG, Weemaes C, van Deuren M, Nicolai J, Wevers RA, Willemsen MA. Alpha-fetoprotein, a fascinating protein and biomarker in neurology. Eur J Paediatr Neurol 2014; 18:243-8. [PMID: 24120489 DOI: 10.1016/j.ejpn.2013.09.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 08/25/2013] [Accepted: 09/14/2013] [Indexed: 12/29/2022]
Abstract
Alpha-fetoprotein (AFP) is present in fetal serum in concentrations up to 5,000,000 μg/l. After birth, AFP gene expression is turned down with a subsequent fall of the serum concentrations of this albumin-like protein to 'adult values' of circa 0.5-15 μg/l from the age of 2 years onwards. Irrespective of its assumed important functions, individuals with AFP deficiency appear fully healthy. The other way around, the presence of AFP in the circulation after the first years of life doesn't seem to harm, since individuals with 'hereditary persistence of AFP' are also without clinical abnormalities. During pregnancy, AFP (in maternal serum) has long been recognized as a marker for congenital anomalies of the fetus. Equally well known is AFP as biomarker for hepatocellular carcinoma and some other malignancies. There are at least four neurodegenerative disorders, all inherited as autosomal recessive traits and characterized by the presence of cerebellar ataxia, abnormal ocular movements, and neuropathy, for which an elevated concentration of serum AFP is an important diagnostic biomarker. The availability of a reliable biomarker is not only important during screening or diagnostic processes, but is also relevant for objective follow-up during (future) therapeutic interventions.
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Affiliation(s)
- J H Schieving
- Department of Pediatric Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
| | - M de Vries
- Department of Pediatrics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - J M G van Vugt
- Department of Obstetrics and Gynaecology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - C Weemaes
- Department of Pediatrics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - M van Deuren
- Department of Internal Medicine, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - J Nicolai
- Department of Neurology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - R A Wevers
- Department of Laboratory Medicine, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - M A Willemsen
- Department of Pediatric Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Oczkowska A, Kozubski W, Lianeri M, Dorszewska J. Genetic variants in diseases of the extrapyramidal system. Curr Genomics 2014; 15:18-27. [PMID: 24653660 PMCID: PMC3958955 DOI: 10.2174/1389202914666131210213327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2013] [Revised: 11/12/2013] [Accepted: 11/28/2013] [Indexed: 01/23/2023] Open
Abstract
Knowledge on the genetics of movement disorders has advanced significantly in recent years. It is now recognized that disorders of the basal ganglia have genetic basis and it is suggested that molecular genetic data will provide clues to the pathophysiology of normal and abnormal motor control. Progress in molecular genetic studies, leading to the detection of genetic mutations and loci, has contributed to the understanding of mechanisms of neurodegeneration and has helped clarify the pathogenesis of some neurodegenerative diseases. Molecular studies have also found application in the diagnosis of neurodegenerative diseases, increasing the range of genetic counseling and enabling a more accurate diagno-sis. It seems that understanding pathogenic processes and the significant role of genetics has led to many experiments that may in the future will result in more effective treatment of such diseases as Parkinson’s or Huntington’s. Currently used molecular diagnostics based on DNA analysis can identify 9 neurodegenerative diseases, including spinal cerebellar ataxia inherited in an autosomal dominant manner, dentate-rubro-pallido-luysian atrophy, Friedreich’s disease, ataxia with ocu-lomotorapraxia, Huntington's disease, dystonia type 1, Wilson’s disease, and some cases of Parkinson's disease.
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Affiliation(s)
- Anna Oczkowska
- Laboratory of Neurobiology, Department of Neurology, PoznanUniversity of Medical Sciences, Poznan, Poland
| | - Wojciech Kozubski
- Department of Neurology, PoznanUniversity of Medical Sciences, Poznan, Poland
| | - Margarita Lianeri
- Department of Biochemistry and Molecular Biology,PoznanUniversity of Medical Sciences, Poznan, Poland
| | - Jolanta Dorszewska
- Laboratory of Neurobiology, Department of Neurology, PoznanUniversity of Medical Sciences, Poznan, Poland
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Panouillères M, Frismand S, Sillan O, Urquizar C, Vighetto A, Pélisson D, Tilikete C. Saccades and eye-head coordination in ataxia with oculomotor apraxia type 2. THE CEREBELLUM 2014; 12:557-67. [PMID: 23475383 DOI: 10.1007/s12311-013-0463-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is one of the most frequent autosomal recessive cerebellar ataxias. Oculomotor apraxia refers to horizontal gaze failure due to deficits in voluntary/reactive eye movements. These deficits can manifest as increased latency and/or hypometria of saccades with a staircase pattern and are frequently associated with compensatory head thrust movements. Oculomotor disturbances associated with AOA2 have been poorly studied mainly because the diagnosis of oculomotor apraxia was based on the presence of compensatory head thrusts. The aim of this study was to characterise the nature of horizontal gaze failure in patients with AOA2 and to demonstrate oculomotor apraxia even in the absence of head thrusts. Five patients with AOA2, without head thrusts, were tested in saccadic tasks with the head restrained or free to move and their performance was compared to a group of six healthy participants. The most salient deficit of the patients was saccadic hypometria with a typical staircase pattern. Saccade latency in the patients was longer than controls only for memory-guided saccades. In the head-free condition, head movements were delayed relative to the eye and their amplitude and velocity were strongly reduced compared to controls. Our study emphasises that in AOA2, hypometric saccades with a staircase pattern are a more reliable sign of oculomotor apraxia than head thrust movements. In addition, the variety of eye and head movements' deficits suggests that, although the main neural degeneration in AOA2 affects the cerebellum, this disease affects other structures.
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Affiliation(s)
- Muriel Panouillères
- INSERM U1028; CNRS UMR5292; Lyon Neuroscience Research Center, ImpAct Team, Bron, 69676, France.
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Nanetti L, Cavalieri S, Pensato V, Erbetta A, Pareyson D, Panzeri M, Zorzi G, Antozzi C, Moroni I, Gellera C, Brusco A, Mariotti C. SETX mutations are a frequent genetic cause of juvenile and adult onset cerebellar ataxia with neuropathy and elevated serum alpha-fetoprotein. Orphanet J Rare Dis 2013; 8:123. [PMID: 23941260 PMCID: PMC3751478 DOI: 10.1186/1750-1172-8-123] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/01/2013] [Indexed: 12/12/2022] Open
Abstract
Objectives/background Ataxia with oculomotor apraxia defines a group of genetically distinct recessive ataxias including ataxia-telangectasia (A-T, ATM gene), ataxia with oculomotor apraxia type 1 (AOA1, APTX gene) and type 2 (AOA2, SETX gene). Although, a few unique clinical features differentiate each of these forms, the patients also share common clinical signs, such as the presence of cerebellar atrophy, sensorimotor axonal neuropathy, and elevated alpha-fetoprotein (AFP) serum level. Materials and methods We selected 22 Italian patients from 21 families, presenting progressive cerebellar ataxia, axonal neuropathy, and elevated serum AFP. We screened the coding regions of ATM, APTX and SETX genes for point mutations by direct sequencing or DHPLC, and searched genomic rearrangements in SETX by MLPA analysis. In selected cases, quantification of ATM and senataxin proteins was performed by Western blot. Clinical, neurophysiological, and neuroimaging data were collected. Results Thirteen patients (12 families) carried SETX mutations (AOA2, 57%), two were mutated in ATM (A-T), and three in APTX (AOA1). In three remaining patients, we could not find pathogenic mutations, and in one case we found, in homozygosis, the SETX p.K992R polymorphism (population frequency 1-2%). In AOA2 cases, we identified 14 novel and three reported SETX mutations. Signs at onset were gait ataxia and facial dyskinesia, and the age ranged between 11 and 18 years. None had obvious oculomotor apraxia at the latest examination (age 14–45 years). The patient carrying the p.K992R SETX polymorphism had a phenotype similar to that of the diagnosed AOA2 patients, while the other three undiagnosed subjects had a very late onset and a few distinguishing clinical features. Discussion and conclusions We describe a large series of 13 AOA2 Italian patients. The phenotype was consistent with previous descriptions of AOA2, except for a higher frequency of strabism, and for the absence of oculomotor apraxia. In our survey ~60% of juvenile-to-adult cases with cerebellar ataxia, sensorimotor neuropathy and increased AFP are due to mutations in the SETX gene, and a smaller percentage to APTX and ATM gene mutations.
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Affiliation(s)
- Lorenzo Nanetti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Clinical and molecular findings of ataxia with oculomotor apraxia type 2 (AOA2) in 5 Tunisian families. ACTA ACUST UNITED AC 2013; 21:241-5. [PMID: 23111195 DOI: 10.1097/pdm.0b013e318257ad9a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is a recently described autosomal recessive cerebellar ataxia caused by mutations in the SETX gene. It is a rare monogenic disease characterized by progressive cerebellar ataxia, oculomotor apraxia, axonal sensorimotor neuropathy, and an elevated serum α-fetoprotein level. To date, >100 AOA2 patients have been described and 75 different mutations in the SETX gene have been identified. We report here the clinical and genetic findings of 13 AOA2 patients from 5 unrelated Tunisian consanguineous families. DNA was collected from probands and available family members, and the 24 SETX exons were screened by direct sequencing. Four different homozygous SETX gene mutations were identified. The missense mutation 915G>T [W305C] has been described previously in Algeria. The 3 other SETX mutations are novel, including a missense mutation c.7231C>T [R 2380 W], a nonsense mutation c.6475 C>T [R2098X], and a deletion c.7180-7183delAAAA [D2332fsX2343]. More extensive screening by molecular genetic analysis of SETX in patients with Friedreich ataxia-like phenotype may show that AOA2 is more common in Tunisia than previously thought.
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Reynolds JJ, Stewart GS. A single strand that links multiple neuropathologies in human disease. ACTA ACUST UNITED AC 2013; 136:14-27. [PMID: 23365091 DOI: 10.1093/brain/aws310] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The development of the human central nervous system is a complex process involving highly coordinated periods of neuronal proliferation, migration and differentiation. Disruptions in these neurodevelopmental processes can result in microcephaly, a neuropathological disorder characterized by a reduction in skull circumference and total brain volume, whereas a failure to maintain neuronal health in the adult brain can lead to progressive neurodegeneration. Defects in the cellular pathways that detect and repair DNA damage are a common cause of both these neuropathologies and are associated with a growing number of hereditary human disorders. In particular, defects in the repair of DNA single strand breaks, one of the most commonly occurring types of DNA lesion, have been associated with three neuropathological diseases: ataxia oculomotor apraxia 1, spinocerebellar ataxia with neuronal neuropathy 1 and microcephaly, early-onset, intractable seizures and developmental delay. A striking similarity between these three human diseases is that they are all caused by mutations in DNA end processing factors, suggesting that a particularly crucial stage of DNA single strand break repair is the repair of breaks with 'damaged' termini. Additionally all three disorders lack any extraneurological symptoms, such as immunodeficiency and cancer predisposition, which are typically found in other human diseases associated with defective DNA repair. However despite these similarities, two of these disorders present with progressive cerebellar degeneration, whereas the third presents with severe microcephaly. This review discusses the molecular defects behind these disorders and presents several hypotheses based on current literature on a number of important questions, in particular, how do mutations in different end processing factors within the same DNA repair pathway lead to such different neuropathologies?
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Affiliation(s)
- John J Reynolds
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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Clausi S, De Luca M, Chiricozzi FR, Tedesco AM, Casali C, Molinari M, Leggio MG. Oculomotor deficits affect neuropsychological performance in oculomotor apraxia type 2. Cortex 2013; 49:691-701. [DOI: 10.1016/j.cortex.2012.02.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 11/22/2011] [Accepted: 02/21/2012] [Indexed: 11/24/2022]
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Affiliation(s)
- Mathieu Anheim
- Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Department of Genetics and Cytogenetics, Paris, France.
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Abstract
The neural centers in the cerebral hemispheres, both cortex and basal ganglia, involved in the generation of saccadic and smooth pursuit eye movements have been well delineated in terms of their location and function. For the generation of saccades these include the frontal eye fields, the supplementary eye field, and the intraparietal sulcus, and in the basal ganglia the caudate nucleus and the substantia nigra, pars compacta. The generation of pursuit eye movements involves the middle temporal (area V5) and medial superior temporal areas and the frontal eye field. These centers and their connections are disturbed not only in acute and chronic lesions such as cerebral infarction, but also in a wide variety of neurodegenerative diseases. In certain of these conditions, such as patients with cortical dementias and basal ganglia disorders, correct interpretation of the resulting eye movement abnormalities can contribute to differentiating between a range of differential diagnoses.
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Affiliation(s)
- Christopher Kennard
- Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Headington, Oxford, UK.
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Anheim M. [Autosomal recessive cerebellar ataxias]. Rev Neurol (Paris) 2010; 167:372-84. [PMID: 21087783 DOI: 10.1016/j.neurol.2010.07.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/13/2010] [Accepted: 07/20/2010] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Autosomal recessive cerebellar ataxias (ARCA) are heterogeneous and complex inherited neurodegenerative diseases that may affect the cerebellum and/or the spinocerebellar tract, the posterior column of the spinal cord and the peripheral nerves. Cerebellar ataxia is frequently proeminent and mostly associated with several neurological or extra-neurological signs, leading to a major disability before the age of 30. STATE OF ART Friedreich's ataxia (FRDA) is clearly the most frequent ARCA and several rarer entities have been described during the past fifteen years such as ataxia with oculomotor apraxia type 1 (AOA1) and type 2 (AOA2), ataxia with vitamin E deficiency (AVED) and autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS). The ACAR are characterized by both allelic and non-allelic genetic heterogeneity. They may be divided into three groups: spino-cerebellar ataxia with pure sensory neuropathy; cerebellar ataxia with sensori-motor axonal neuropathy; pure cerebellar ataxia (i.e. ataxia of purely cerebellar origin that may be associated with other symptoms). Common physiological pathways are involved in several ARCA, such as DNA repair deficiency (AOA1, ataxia telangiectasia [AT]…), RNA termination disorder (AOA2), mitochondrial defect (FRDA, sensory ataxic neuropathy with dysarthria and ophthalmoplegia [Sando]…), lipoprotein assembly defects (AVED, abetalipoproteinemia [ABL]), chaperon protein disorders (ARSACS, Marinesco-Sjögren syndrome [MSS]) or peroxysomal diseases (Refsum disease [RD]). PERSPECTIVES New nanotechnology methods and high throughput gene analysis as well as bioinformatics should lead to the identification of several new ARCAs in the next few years despite the rarity of these entities. However, the challenge of the next decades will be the discovery of efficient treatments for these disabling neurodegenerative disorders. CONCLUSION Clinicians should be aware of the more frequent ARCAs, especially FRDA, in addition to ARCAs for which treatment is available (FRDA, AVED, ABL and RD for instance).
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Affiliation(s)
- M Anheim
- Service de neurogénétique, hôpital de la Pitié-Salpêtrière, 75651 Paris, France.
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Iltis I, Hutter D, Bushara KO, Clark HB, Gross M, Eberly LE, Gomez CM, Oz G. (1)H MR spectroscopy in Friedreich's ataxia and ataxia with oculomotor apraxia type 2. Brain Res 2010; 1358:200-10. [PMID: 20713024 DOI: 10.1016/j.brainres.2010.08.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2010] [Revised: 08/07/2010] [Accepted: 08/09/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND AND AIM Friedreich's ataxia (FRDA) and ataxia with oculomotor apraxia type 2 (AOA2) are the two most frequent forms of autosomal recessive cerebellar ataxias. However, brain metabolism in these disorders is poorly characterized and biomarkers of the disease progression are lacking. We aimed at assessing the neurochemical profile of the pons, the cerebellar hemisphere and the vermis in patients with FRDA and AOA2 to identify potential biomarkers of these diseases. METHODS Short-echo, single-voxel proton ((1)H) magnetic resonance spectroscopy data were acquired from 8 volunteers with FRDA, 9 volunteers with AOA2, and 38 control volunteers at 4T. Disease severity was assessed by the Friedreich's Ataxia Rating Scale (FARS). RESULTS Neuronal loss/dysfunction was indicated in the cerebellar vermis and hemispheres in both diseases by lower total N-acetylaspartate levels than controls. The putative gliosis marker myo-inositol was higher than controls in the vermis and pons in AOA2 and in the vermis in FRDA. Total creatine, another potential gliosis marker, was higher in the cerebellar hemispheres in FRDA relative to controls. Higher glutamine in FRDA and lower glutamate in AOA2 than controls were observed in the vermis, indicating different mechanisms possibly leading to altered glutamatergic neurotransmission. In AOA2, total N-acetylaspartate levels in the cerebellum strongly correlated with the FARS score (p<0.01). CONCLUSION Distinct neurochemical patterns were observed in the two patient populations, warranting further studies with larger patient populations to determine if the alterations in metabolite levels observed here may be utilized to monitor disease progression and treatment.
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Affiliation(s)
- Isabelle Iltis
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN 55455, USA.
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RNA processing pathways in amyotrophic lateral sclerosis. Neurogenetics 2010; 11:275-90. [PMID: 20349096 DOI: 10.1007/s10048-010-0239-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2009] [Accepted: 02/24/2010] [Indexed: 12/12/2022]
Abstract
RNA processing is a tightly regulated, highly complex pathway which includes RNA transcription, pre-mRNA splicing, editing, transportation, translation, and degradation of RNA. Over the past few years, several RNA processing genes have been shown to be mutated or genetically associated with amyotrophic lateral sclerosis (ALS), including the RNA-binding proteins TDP-43 and FUS/TLS. These findings suggest that RNA processing may represent a common pathogenic mechanism involved in development of ALS. In this review, we will discuss six ALS-related, RNA processing genes including their discovery, function, and commonalities.
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Fogel BL, Lee JY, Perlman S. Aberrant splicing of the senataxin gene in a patient with ataxia with oculomotor apraxia type 2. THE CEREBELLUM 2010; 8:448-53. [PMID: 19727998 PMCID: PMC2788137 DOI: 10.1007/s12311-009-0130-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is caused by a diversity of mutations within the coding region of the senataxin gene. Recently, rare noncoding senataxin mutations affecting RNA processing have been identified in AOA2. Here, we report the case of an 18-year-old woman, with classic clinical features of AOA2, who was found to harbor a mutation within senataxin intron 16. This mutation disrupts the local 5' splice site architecture via a novel intronic frameshift mechanism, causing skipping of exon 16 with predicted disruption of the conserved DNA/RNA helicase domain. RNA processing mutations expand the growing complexity of pathogenic senataxin mutations.
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Affiliation(s)
- Brent L Fogel
- Department of Neurology, UCLA Program in Neurogenetics, David Geffen School of Medicine, University of California at Los Angeles, 710 Westwood Plaza, Los Angeles, CA 90095, USA.
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Embiruçu EK, Martyn ML, Schlesinger D, Kok F. Autosomal recessive ataxias: 20 types, and counting. ARQUIVOS DE NEURO-PSIQUIATRIA 2009; 67:1143-56. [DOI: 10.1590/s0004-282x2009000600036] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 09/22/2009] [Indexed: 11/22/2022]
Abstract
More than 140 years after the first description of Friedreich ataxia, autosomal recessive ataxias have become one of the more complex fields in Neurogenetics. Currently this group of diseases contains more than 20 clinical entities and an even larger number of associated genes. Some disorders are very rare, restricted to isolated populations, and others are found worldwide. An expressive number of recessive ataxias are treatable, and responsibility for an accurate diagnosis is high. The purpose of this review is to update the practitioner on clinical and pathophysiological aspects of these disorders and to present an algorithm to guide the diagnosis.
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Affiliation(s)
| | | | - David Schlesinger
- University of São Paulo, Brazil; Universidade de São Paulo; Universidade de São Paulo
| | - Fernando Kok
- University of São Paulo, Brazil; Universidade de São Paulo
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Nakamura K, Yoshida K, Makishita H, Kitamura E, Hashimoto S, Ikeda SI. A novel nonsense mutation in a Japanese family with ataxia with oculomotor apraxia type 2 (AOA2). J Hum Genet 2009; 54:746-8. [DOI: 10.1038/jhg.2009.104] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Anheim M, Monga B, Fleury M, Charles P, Barbot C, Salih M, Delaunoy JP, Fritsch M, Arning L, Synofzik M, Schöls L, Sequeiros J, Goizet C, Marelli C, Le Ber I, Koht J, Gazulla J, De Bleecker J, Mukhtar M, Drouot N, Ali-Pacha L, Benhassine T, Chbicheb M, M'Zahem A, Hamri A, Chabrol B, Pouget J, Murphy R, Watanabe M, Coutinho P, Tazir M, Durr A, Brice A, Tranchant C, Koenig M. Ataxia with oculomotor apraxia type 2: clinical, biological and genotype/phenotype correlation study of a cohort of 90 patients. ACTA ACUST UNITED AC 2009; 132:2688-98. [PMID: 19696032 DOI: 10.1093/brain/awp211] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Ataxia with oculomotor apraxia type 2 (AOA2) is an autosomal recessive disease due to mutations in the senataxin gene, causing progressive cerebellar ataxia with peripheral neuropathy, cerebellar atrophy, occasional oculomotor apraxia and elevated alpha-feto-protein (AFP) serum level. We compiled a series of 67 previously reported and 58 novel ataxic patients who underwent senataxin gene sequencing because of suspected AOA2. An AOA2 diagnosis was established for 90 patients, originating from 15 countries worldwide, and 25 new senataxin gene mutations were found. In patients with AOA2, median AFP serum level was 31.0 microg/l at diagnosis, which was higher than the median AFP level of AOA2 negative patients: 13.8 microg/l, P = 0.0004; itself higher than the normal level (3.4 microg/l, range from 0.5 to 17.2 microg/l) because elevated AFP was one of the possible selection criteria. Polyneuropathy was found in 97.5% of AOA2 patients, cerebellar atrophy in 96%, occasional oculomotor apraxia in 51%, pyramidal signs in 20.5%, head tremor in 14%, dystonia in 13.5%, strabismus in 12.3% and chorea in 9.5%. No patient was lacking both peripheral neuropathy and cerebellar atrophy. The age at onset and presence of occasional oculomotor apraxia were negatively correlated to the progression rate of the disease (P = 0.03 and P = 0.009, respectively), whereas strabismus was positively correlated to the progression rate (P = 0.03). An increased AFP level as well as cerebellar atrophy seem to be stable in the course of the disease and to occur mostly at or before the onset of the disease. One of the two patients with a normal AFP level at diagnosis had high AFP levels 4 years later, while the other had borderline levels. The probability of missing AOA2 diagnosis, in case of sequencing senataxin gene only in non-Friedreich ataxia non-ataxia-telangiectasia ataxic patients with AFP level > or =7 microg/l, is 0.23% and the probability for a non-Friedreich ataxia non-ataxia-telangiectasia ataxic patient to be affected with AOA2 with AFP levels > or =7 microg/l is 46%. Therefore, selection of patients with an AFP level above 7 microg/l for senataxin gene sequencing is a good strategy for AOA2 diagnosis. Pyramidal signs and dystonia were more frequent and disease was less severe with missense mutations in the helicase domain of senataxin gene than with missense mutations out of helicase domain and deletion and nonsense mutations (P = 0.001, P = 0.008 and P = 0.01, respectively). The lack of pyramidal signs in most patients may be explained by masking due to severe motor neuropathy.
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Affiliation(s)
- M Anheim
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS, Université de Strasbourg, INSERM, Illkirch, France.
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Airoldi G, Guidarelli A, Cantoni O, Panzeri C, Vantaggiato C, Bonato S, Grazia D’Angelo M, Falcone S, De Palma C, Tonelli A, Crimella C, Bondioni S, Bresolin N, Clementi E, Bassi MT. Characterization of two novel SETX mutations in AOA2 patients reveals aspects of the pathophysiological role of senataxin. Neurogenetics 2009; 11:91-100. [DOI: 10.1007/s10048-009-0206-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Accepted: 06/25/2009] [Indexed: 11/30/2022]
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Faridy EE, Yang WZ. Role of hyperventilation in hypoxia on lung growth in rats. BMC MEDICAL GENETICS 1989; 10:87. [PMID: 19744353 PMCID: PMC2749023 DOI: 10.1186/1471-2350-10-87] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Accepted: 09/11/2009] [Indexed: 01/22/2023]
Abstract
Background The autosomal recessively inherited ataxia with oculomotor apraxia 2 (AOA2) is a neurodegenerative disorder characterized by juvenile or adolescent age of onset, gait ataxia, cerebellar atrophy, axonal sensorimotor neuropathy, oculomotor apraxia, and elevated serum AFP levels. AOA2 is caused by mutations within the senataxin gene (SETX). The majority of known mutations are nonsense, missense, and splice site mutations, as well as small deletions and insertions. Methods To detect mutations in patients showing a clinical phenotype consistent with AOA2, the coding region including splice sites of the SETX gene was sequenced and dosage analyses for all exons were performed on genomic DNA. The sequence of cDNA fragments of alternative transcripts isolated after RT-PCR was determined. Results Sequence analyses of the SETX gene in four patients revealed a heterozygous nonsense mutation or a 4 bp deletion in three cases. In another patient, PCR amplification of exon 11 to 15 dropped out. Dosage analyses and breakpoint localisation yielded a 1.3 kb LINE1 insertion in exon 12 (patient P1) and a 6.1 kb deletion between intron 11 and intron 14 (patient P2) in addition to the heterozygous nonsense mutation R1606X. Patient P3 was compound heterozygous for a 4 bp deletion in exon 10 and a 20.7 kb deletion between intron 10 and 15. This deletion was present in a homozygous state in patient P4. Conclusion Our findings indicate that gross mutations seem to be a frequent cause of AOA2 and reveal the importance of additional copy number analysis for routine diagnostics.
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Affiliation(s)
- E E Faridy
- Department of Physiology, University of Manitoba, Winnipeg, Canada
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