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Manzoor U, Ali A, Ali SL, Abdelkarem O, Kanwal S, Alotaibi SS, Baazeem A, Baiduissenova A, Yktiyarov A, Hajar A, Olzhabay A. Mutational screening of GDAP1 in dysphonia associated with Charcot-Marie-Tooth disease: clinical insights and phenotypic effects. J Genet Eng Biotechnol 2023; 21:119. [PMID: 37966693 PMCID: PMC10651813 DOI: 10.1186/s43141-023-00568-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 10/26/2023] [Indexed: 11/16/2023]
Abstract
INTRODUCTION Mutations in GDAP1 (Ganglioside-induced differentiation-associated protein 1) gene are linked to Charcot-Marie-Tooth disease (CMT), a Heterogenous group of disorders with multiple phenotypes, characterized by peripheral nerve dysfunction that can lead to vocal cord paralysis and diaphragmatic dysfunction. MAIN BODY All three affected children of this chosen family have manifested the same clinical symptoms with progressive weakness, mild sensory impairment, and absent tendon reflexes in their early years. Electrodiagnostic analysis displayed an axonal type of neuropathy in affected patients. Sequencing of the GDAP1 gene was requested for all members of the family. Diagnostic assessments included pulmonary and vocal cord function tests, as well as phrenic and peripheral nerve conduction studies. Pathogenicity of GDAP1 variant p.Pro419Leu with axonal CMT2 and autosomal recessive inheritance was confirmed via in silico analysis. Patients with GDAP1 mutations showed dysphonia, speech difficulties, and the characteristic symptoms of CMT. The severity of symptoms correlated with the presence of a type of GDAP1 mutation. Patients with normal vocal cords and pulmonary function exhibited milder symptoms compared to those with GDAP1 mutations. Our study provides clinical insights into the phenotypic effects of GDAP1 mutations in CMT patients. The findings highlight the adverse clinical course and severe disability associated with GDAP1 mutations, including weak limb and laryngeal muscles. CONCLUSION Patients with GDAP1 mutations and autosomal recessive neuropathy present with dysphonia and require interventions such as surgery, braces, physical therapy, and exercise. Early diagnosis and comprehensive clinical evaluations are crucial for managing CMT patients with GDAP1 mutations.
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Affiliation(s)
- Uzma Manzoor
- Department of Clinical Biochemistry, COMSATS University Islamabad, Sahiwal Campus, Sahiwal, Pakistan.
| | - Awais Ali
- Department of Biochemistry, Abdul wali Khan University Mardan, Mardan, 23200, Pakistan
| | - S Luqman Ali
- Department of Biochemistry, Abdul wali Khan University Mardan, Mardan, 23200, Pakistan
| | - Omneya Abdelkarem
- Department of Chemical Pathology, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Sumaira Kanwal
- Department of Clinical Biochemistry, COMSATS University Islamabad, Sahiwal Campus, Sahiwal, Pakistan
| | - Saqer S Alotaibi
- Department of Biotechnology, College of Science, Taif University, P.O.Box 11099, 21944, Taif, Saudi Arabia
| | - Alaa Baazeem
- Department of Biology, College of Science, Taif University, P.O. Box 11099, 21944, Taif, Saudi Arabia
| | - Aliya Baiduissenova
- Department of Microbiology and Virology, Astana Medical University, Astana City, 010000, Kazakhstan
| | - Ayaz Yktiyarov
- Department of Microbiology and Virology, Astana Medical University, Astana City, 010000, Kazakhstan
| | - Azraida Hajar
- Department of Biology, Faculty of Sciences Semlalia, Cadi Ayyad University, Marrakech, Morocco
| | - Abay Olzhabay
- Department of Otorhinolaryngology, Astana Medical University, Astana City, 010000, Kazakhstan
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Aoki S, Nagashima K, Shibata M, Kasahara H, Fujita Y, Hashiguchi A, Takashima H, Ikeda Y. Sibling Cases of Charcot-Marie-Tooth Disease Type 4H with a Homozygous FGD4 Mutation and Cauda Equina Thickening. Intern Med 2021; 60:3975-3981. [PMID: 34148957 PMCID: PMC8758460 DOI: 10.2169/internalmedicine.7247-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Charcot-Marie-Tooth disease type 4H (CMT4H) is an autosomal recessive inherited demyelinating neuropathy caused by an FYVE, RhoGEF, and a PH domain-containing protein 4 (FGD4) gene mutation. CMT4H is characterized by an early onset, slow progression, scoliosis, distal muscle atrophy, and foot deformities. We herein present sibling cases of CMT4H with a homozygous mutation in the FGD4 gene. Both patients exhibited cauda equina thickening on magnetic resonance imaging, which had not been reported among the previous CMT4H cases. This is the first report of CMT4H with a homozygous FGD4 c.1730G>A (p.Arg577Gln) mutation showing mild progression and cauda equina thickening.
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Affiliation(s)
- Sho Aoki
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
| | - Kazuaki Nagashima
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
| | - Makoto Shibata
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
| | - Hiroo Kasahara
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
| | - Yukio Fujita
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
| | - Akihiro Hashiguchi
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Yoshio Ikeda
- Department of Neurology, Gunma University Graduate School of Medicine, Japan
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Choi HW. Fasciculations in Children. Pediatr Neurol 2021; 125:40-47. [PMID: 34628142 DOI: 10.1016/j.pediatrneurol.2021.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 08/19/2021] [Accepted: 08/28/2021] [Indexed: 11/26/2022]
Abstract
Fasciculations are the most common form of spontaneous muscle contraction. They frequently occur in healthy individuals. However, there are a minority of situations that fasciculations are observed in association with specific neurologic disorders. Publications concerning the evaluation of pediatric patients experiencing fasciculations are limited. These children may undergo invasive or expensive diagnostic investigations that are unnecessary. Moreover, without careful consideration of differential diagnoses, rare neuromuscular disorders that present with fasciculations in the pediatric age group can be under-recognized by pediatric neurologists. This review examines the most important pediatric disorders presenting with fasciculations and other spontaneous muscle contractions to guide pediatric neurologists in evaluating these children.
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Affiliation(s)
- Hyoung Won Choi
- Division of Pediatric Neurology, University of Pittsburgh Medical Center Children's Hospital of Pittsburgh, Lemoyne, Pennsylvania.
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Kontogeorgiou Z, Voudommatis C, Kartanou C, Pandis D, Breza M, Zambelis T, Stefanis L, Panas M, Koutsis G, Karadima G. HINT1-related neuropathy in Greek patients with Charcot-Marie-Tooth disease. J Peripher Nerv Syst 2021; 26:444-448. [PMID: 34694653 DOI: 10.1111/jns.12473] [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] [Received: 08/11/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 11/29/2022]
Abstract
Autosomal recessive axonal neuropathy with neuromyotonia (ARAN-NM) is a rare hereditary neuropathy within the Charcot-Marie-Tooth disease (CMT) spectrum, linked to mutations in the histidine triad nucleotide-binding protein 1 (HINT1) gene. HINT1-related neuropathy is particularly common in selected populations from Central and Eastern Europe but rare in Western European cohorts. It has not been investigated to date in the Greek population. We presently investigated the frequency of HINT1-neuropathy in a selected cohort of 42 Greek index patients with autosomal recessive or sporadic axonal hereditary neuropathy according to standard molecular genetics procedures. We identified 4 patients with biallelic mutations in HINT1, comprising 9.5% of all cases and 44.4% of cases also displaying neuromyotonia. The c.110G> C (p.Arg37Pro) HINT1 mutation was present in all cases (2 homozygous) and the c.250T> C (p.Cys84Arg) in 2 cases (compound heterozygous). HINT1-related neuropathy patients were characterized by early onset and neuromyotonia. Two patients had noteworthy clinical features, one case developing myoclonic epilepsy and the other displaying "adducted thumbs." We conclude that HINT1-related neuropathy is common in selected Greek patients with hereditary neuropathy within the CMT spectrum, in accordance with some, but not all, European populations.
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Affiliation(s)
- Zoi Kontogeorgiou
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Charalampos Voudommatis
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Chrisoula Kartanou
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Dionysis Pandis
- Clinical Neurophysiology Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marianthi Breza
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Thomas Zambelis
- Clinical Neurophysiology Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Leonidas Stefanis
- 1st Department of Neurology, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Marios Panas
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgios Koutsis
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Georgia Karadima
- Neurogenetics Unit, 1st Department of Neurology, School of Medicine, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
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Candayan A, Çakar A, Yunisova G, Özdağ Acarlı AN, Atkinson D, Topaloğlu P, Durmuş H, Yapıcı Z, Jordanova A, Parman Y, Battaloğlu E. Genetic Survey of Autosomal Recessive Peripheral Neuropathy Cases Unravels High Genetic Heterogeneity in a Turkish Cohort. NEUROLOGY-GENETICS 2021; 7:e621. [PMID: 34476298 PMCID: PMC8409130 DOI: 10.1212/nxg.0000000000000621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/15/2021] [Indexed: 11/15/2022]
Abstract
Background and Objectives Inherited peripheral neuropathies (IPNs) are a group of genetic disorders of the peripheral nervous system in which neuropathy is the only or the most predominant clinical feature. The most common type of IPN is Charcot-Marie-Tooth (CMT) disease. Autosomal recessive CMT (ARCMT) is generally more severe than dominant CMT and its genetic basis is poorly understood due to high clinical and genetic diversity. Here, we report clinical and genetic findings from 56 consanguineous Turkish families initially diagnosed with CMT disease. Methods We initially screened the GDAP1 gene in our cohort as it is the most commonly mutated ARCMT gene. Next, whole-exome sequencing and homozygosity mapping based on whole-exome sequencing (HOMWES) analysis was performed. To understand the molecular impact of candidate causative genes, functional analyses were performed in patient primary fibroblasts. Results Biallelic recurrent mutations in the GDAP1 gene have been identified in 6 patients. Whole-exome sequencing and HOMWES analysis revealed 16 recurrent and 13 novel disease-causing alleles in known IPN-related genes and 2 novel candidate genes: 1 for a CMT-like disease and 1 for autosomal recessive cerebellar ataxia with axonal neuropathy. We have achieved a potential genetic diagnosis rate of 62.5% (35/56 families) in our cohort. Considering only the variants that meet the American College for Medical Genetics and Genomics (ACMG) classification as pathogenic or likely pathogenic, the definitive diagnosis rate was 55.35% (31/56 families). Discussion This study paints a genetic landscape of the Turkish ARCMT population and reports additional candidate genes that might help enlighten the mechanism of pathogenesis of the disease.
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Affiliation(s)
- Ayşe Candayan
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Arman Çakar
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Gulshan Yunisova
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Ayşe Nur Özdağ Acarlı
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Derek Atkinson
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Pınar Topaloğlu
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Hacer Durmuş
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Zuhal Yapıcı
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Albena Jordanova
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Yeşim Parman
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
| | - Esra Battaloğlu
- Department of Molecular Biology and Genetics (A.C., E.B.), Boğaziçi University, Istanbul, Turkey; Neuromuscular Unit (A.Ç., G.Y., A.N.Ö.A., H.D., Y.P.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; Molecular Neurogenomics Group (D.A., A.J.), VIB-UAntwerp Center for Molecular Neurology, University of Antwerp, Belgium; Department of Epigenetics (D.A.), Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Division of Child Neurology (P.T., Z.Y.), Department of Neurology, Istanbul Faculty of Medicine, Istanbul University, Turkey; and Molecular Medicine Center (A.J.), Department of Medical Chemistry and Biochemistry, Medical University-Sofia, Bulgaria
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Beijer D, Baets J. The expanding genetic landscape of hereditary motor neuropathies. Brain 2021; 143:3540-3563. [PMID: 33210134 DOI: 10.1093/brain/awaa311] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/15/2020] [Accepted: 07/27/2020] [Indexed: 12/12/2022] Open
Abstract
Hereditary motor neuropathies are clinically and genetically diverse disorders characterized by length-dependent axonal degeneration of lower motor neurons. Although currently as many as 26 causal genes are known, there is considerable missing heritability compared to other inherited neuropathies such as Charcot-Marie-Tooth disease. Intriguingly, this genetic landscape spans a discrete number of key biological processes within the peripheral nerve. Also, in terms of underlying pathophysiology, hereditary motor neuropathies show striking overlap with several other neuromuscular and neurological disorders. In this review, we provide a current overview of the genetic spectrum of hereditary motor neuropathies highlighting recent reports of novel genes and mutations or recent discoveries in the underlying disease mechanisms. In addition, we link hereditary motor neuropathies with various related disorders by addressing the main affected pathways of disease divided into five major processes: axonal transport, tRNA aminoacylation, RNA metabolism and DNA integrity, ion channels and transporters and endoplasmic reticulum.
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Affiliation(s)
- Danique Beijer
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium
| | - Jonathan Baets
- Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Belgium.,Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Belgium.,Neuromuscular Reference Centre, Department of Neurology, Antwerp University Hospital, Belgium
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Schiavon CR, Shadel GS, Manor U. Impaired Mitochondrial Mobility in Charcot-Marie-Tooth Disease. Front Cell Dev Biol 2021; 9:624823. [PMID: 33598463 PMCID: PMC7882694 DOI: 10.3389/fcell.2021.624823] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 01/05/2021] [Indexed: 12/13/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) disease is a progressive, peripheral neuropathy and the most commonly inherited neurological disorder. Clinical manifestations of CMT mutations are typically limited to peripheral neurons, the longest cells in the body. Currently, mutations in at least 80 different genes are associated with CMT and new mutations are regularly being discovered. A large portion of the proteins mutated in axonal CMT have documented roles in mitochondrial mobility, suggesting that organelle trafficking defects may be a common underlying disease mechanism. This review will focus on the potential role of altered mitochondrial mobility in the pathogenesis of axonal CMT, highlighting the conceptional challenges and potential experimental and therapeutic opportunities presented by this "impaired mobility" model of the disease.
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Affiliation(s)
- Cara R. Schiavon
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Gerald S. Shadel
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, United States
| | - Uri Manor
- Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, United States
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Chen CX, Li JQ, Dong HL, Liu GL, Bai G, Wu ZY. Identification and functional characterization of novel GDAP1 variants in Chinese patients with Charcot-Marie-Tooth disease. Ann Clin Transl Neurol 2020; 7:2381-2392. [PMID: 33136338 PMCID: PMC7732252 DOI: 10.1002/acn3.51233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 09/14/2020] [Accepted: 10/01/2020] [Indexed: 12/12/2022] Open
Abstract
Objective To identify and characterize the pathogenicity of novel variants in Chinese patients with Charcot–Marie–Tooth disease. Methods Multiplex ligation‐dependent probe amplification (MLPA) and whole‐exome sequencing (WES) were performed in 30 unrelated CMT patients. Minigene assay was used to verify the effect of a novel splicing variant (c.694+1G>A) on pre‐mRNA. Primary fibroblast cell lines were established from skin biopsies to characterize the biological effects of the novel variants p.L26R and p.S169fs. The mitochondrial structure was observed by an electron microscope. The expression level of protein was analyzed by Western Blotting. Mitochondrial dynamics and mitochondrial membrane potential (MMP, Δψm) were analyzed via immunofluorescence study. Mitochondrial ATP levels were analyzed via bioluminescence assay. The rate of oxygen consumption was measured with a Seahorse Bioscience XF‐96 extracellular flux analyzer. Results We identified 10 pathogenic variants in three known CMT related genes, including three novel variants (p.L26R, p.S169fs, c.694+1G>A) and one known pathogenic variant (p.R120W) in GDAP1. Further, we described the clinical features of patients carrying pathogenic variants in GDAP1 and found that almost all Chinese CMT patients with GDAP1 variants present axonal type. The effect of c.694+1G>A on pre‐mRNA was verified via minigene splice assay. Cellular biological effects showed ultrastructure damage of mitochondrial, reduced protein levels, different patterns of mitochondrial dynamics, decreased mitochondrial membrane potential (Δψm), ATP content, and defects in respiratory capacity in the patient carrying p.L26R and p.S169fs in GDAP1. Interpretation Our results broaden the genetic spectrum of GDAP1 and provided functional evidence for mitochondrial pathways in the pathogenesis of GDAP1 variants.
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Affiliation(s)
- Cong-Xin Chen
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Jia-Qi Li
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Hai-Lin Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Gong-Lu Liu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Ge Bai
- NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
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Cirak S, Daimagüler HS, Moawia A, Koy A, Yis U. On the differential diagnosis of neuropathy in neurogenetic disorders. MED GENET-BERLIN 2020. [DOI: 10.1515/medgen-2020-2040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Neuropathy might be the presenting or accompanying sign in many neurogenetic and metabolic disorders apart from the classical-peripheral neuropathies or motor-neuron diseases. This causes a diagnostic challenge which is of particular relevance since a number of the underlying diseases could be treated. Thus, we attempt to give a clinical overview on the most common genetic diseases with clinically manifesting neuropathy.
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Affiliation(s)
- Sebahattin Cirak
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Hülya-Sevcan Daimagüler
- Division of Pediatrics Neurology, Department of Pediatrics, Faculty of Medicine , Dokuz Eylul University , Izmir , Turkey
| | - Abubakar Moawia
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Anne Koy
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
- Center for Rare Diseases, Faculty of Medicine and University Hospital Cologne , University of Cologne , Cologne , Germany
| | - Uluc Yis
- Division of Pediatrics Neurology, Department of Pediatrics, Faculty of Medicine , Dokuz Eylul University , Izmir , Turkey
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Abstract
Abstract
Inherited peripheral neuropathy is the most common hereditary neuromuscular disease with a prevalence of about 1:2,500. The most frequent form is Charcot-Marie-Tooth disease (CMT, or hereditary motor and sensory neuropathy [HMSN]). Other clinical entities are hereditary neuropathy with liability to pressure palsies (HNPP), distal hereditary motor neuropathies (dHMN), and hereditary sensory and autonomic neuropathies (HSAN). With the exception of HNPP, which is almost always caused by defects of the PMP22 gene, all other forms show genetic heterogeneity with altogether more than 100 genes involved. Mutation detection rates vary considerably, reaching up to 80 % in demyelinating CMT (CMT1) but are still as low as 10–30 % in axonal CMT (CMT2), dHMN, and HSAN. Based on current information, analysis of only four genes (PMP22, GJB1, MPZ, MFN2) identifies 80–90 % of CMT-causing mutations that can be detected in all known disease genes. For the remaining patients, parallel analysis of multiple neuropathy genes using next-generation sequencing is now replacing phenotype-oriented multistep gene-by-gene sequencing. Such approaches tend to generate a wealth of genetic information that requires comprehensive evaluation of the pathogenic relevance of identified variants. In this review, we present current classification systems, specific phenotypic clues, and diagnostic yields in the different subgroups of hereditary CMT and motor neuropathies.
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11
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MOOSAVI RS, JAHANGIR SOOLTANI N, HOUSHMAND M. Investigation of Mutations in Exon 14 of SH3TC2 Gene and Exon 7 of NDRG1 Gene in Iranian Charcot-Marie-Tooth Disease Type 4 (CMT4D) Patients. IRANIAN JOURNAL OF CHILD NEUROLOGY 2020; 14:93-100. [PMID: 32256628 PMCID: PMC7085125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 03/07/2018] [Accepted: 02/16/2019] [Indexed: 10/29/2022]
Abstract
OBJECTIVES Charcot-Marie-tooth disease type 4 (CMT4D) is an autosomal recessive form of Charcot-Marie-tooth disease with an earlier age of onset and greater severity, compared to other types of this disease. CMT4C and CMT4D are the most prevalent subtypes in Mediterranean countries due to the higher rate of consanguineous marriage. In this study, we aimed to identify p.R148X mutation in NDRG1 gene and p.R1109X mutation in SH3TC2 gene (responsible for CMT4D and CMT4C, respectively) and to investigate other possible nucleotide changes in exon 14 of SH3TC2 gene and exon 7 of NDRG1 gene in an Iranian population. MATERIALS & METHODS A total of 24 CMT4D patients, who were referred to Iran Special Medical Center, were clinically and electrophysiologically evaluated in this study. DNA was extracted from the patients' blood samples. Next, polymerase chain reaction (PCR) assay was carried out, and the products were sequenced and analyzed in FinchTV software. RESULTS None of the target mutations were found in this study. Sequencing of SH3TC2 gene showed SNP rs1025476 (g.57975C>T) in 21 (87.5%) patients, including 7 homozygous and 14 heterozygous individuals. CONCLUSION Despite the high rate of mutations in some populations, it seems that they are very rare in Iranian CMT4D patients. Regarding the association of SNP rs1025476 with CMT4D, further assessments are needed to reach a better understanding of genetic markers and their genetic features and to propose better diagnostic and treatment plans for the Iranian population.
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Affiliation(s)
- Rahmaneh Sadat MOOSAVI
- Science and Research Branch of Islamic Azad University, Islamic Republic of Iran, Niloofar Jahangir Soltani
| | - Niloofar JAHANGIR SOOLTANI
- Department of Medical Biotechnology, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
| | - Massoud HOUSHMAND
- Department of National Institute of Genetic Engineering and Biotechnology, Tehran, Iran
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12
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Mortreux J, Bacquet J, Boyer A, Alazard E, Bellance R, Giguet-Valard AG, Cerino M, Krahn M, Audic F, Chabrol B, Laugel V, Desvignes JP, Béroud C, Nguyen K, Verschueren A, Lévy N, Attarian S, Delague V, Missirian C, Bonello-Palot N. Identification of novel pathogenic copy number variations in Charcot-Marie-Tooth disease. J Hum Genet 2019; 65:313-323. [PMID: 31852984 DOI: 10.1038/s10038-019-0710-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 12/03/2019] [Accepted: 12/08/2019] [Indexed: 12/13/2022]
Abstract
Charcot-Marie-Tooth disease (CMT) is a hereditary sensory-motor neuropathy characterized by a strong clinical and genetic heterogeneity. Over the past few years, with the occurrence of whole-exome sequencing (WES) or whole-genome sequencing (WGS), the molecular diagnosis rate has been improved by allowing the screening of more than 80 genes at one time. In CMT, except the recurrent PMP22 duplication accounting for about 60% of pathogenic variations, pathogenic copy number variations (CNVs) are rarely reported and only a few studies screening specifically CNVs have been performed. The aim of the present study was to screen for CNVs in the most prevalent genes associated with CMT in a cohort of 200 patients negative for the PMP22 duplication. CNVs were screened using the Exome Depth software on next generation sequencing (NGS) data obtained by targeted capture and sequencing of a panel of 81 CMT associated genes. Deleterious CNVs were identified in four patients (2%), in four genes: GDAP1, LRSAM1, GAN, and FGD4. All CNVs were confirmed by high-resolution oligonucleotide array Comparative Genomic Hybridization (aCGH) and/or quantitative PCR. By identifying four new CNVs in four different genes, we demonstrate that, although they are rare mutational events in CMT, CNVs might contribute significantly to mutational spectrum of Charcot-Marie-Tooth disease and should be searched in routine NGS diagnosis. This strategy increases the molecular diagnosis rate of patients with neuropathy.
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Affiliation(s)
- J Mortreux
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - J Bacquet
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - A Boyer
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - E Alazard
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - R Bellance
- Centre de référence Caribéen pour les maladies neuromusculaires, CeRCa, Hôpital Pierre-Zobda-Quitman, CHU de Martinique, France
| | - A G Giguet-Valard
- Centre de référence Caribéen pour les maladies neuromusculaires, CeRCa, Hôpital Pierre-Zobda-Quitman, CHU de Martinique, France
| | - M Cerino
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - M Krahn
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - F Audic
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone enfant, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - B Chabrol
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone enfant, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - V Laugel
- Centre de référence des maladies neuromusculaires, Service de pédiatrie, CHU Strasbourg, France
| | - J P Desvignes
- Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - C Béroud
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - K Nguyen
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - A Verschueren
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone Adulte, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - N Lévy
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - S Attarian
- Centre de référence des maladies neuromusculaires, Hôpital de la Timone Adulte, Assistance-Publique Hôpitaux de Marseille, Marseille, France
| | - V Delague
- Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - C Missirian
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France.,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France
| | - N Bonello-Palot
- Département de génétique médicale, Hôpital Timone enfants, Assistance-Publique Hôpitaux de Marseille, Marseille, France. .,Aix Marseille Univ, INSERM, MMG, U1251, Marseille, France.
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13
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Argente-Escrig H, Sánchez-Monteagudo A, Frasquet M, Millet-Sancho E, Martínez-Rubio MD, Pitarch I, Tomás M, Espinós C, Lupo V, Sevilla T. A very mild phenotype of Charcot-Marie-Tooth disease type 4H caused by two novel mutations in FGD4. J Neurol Sci 2019; 402:156-161. [PMID: 31152969 DOI: 10.1016/j.jns.2019.05.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/04/2019] [Accepted: 05/14/2019] [Indexed: 11/30/2022]
Abstract
BACKGROUND Mutations in the FGD4 gene cause an autosomal recessive demyelinating peripheral neuropathy referred to as CMT4H, characterized by its onset in infancy or early-childhood and its slow progression. METHODS The clinical and genetic status of two patients with CMT4H was studied, performing genetic testing with a panel of genes and analysing FGD4 mRNA expression by quantitative PCR. RESULTS Two novel FGD4 variants (c.514delG and c.2211dupA) were identified in two mildly affected Spanish siblings with CMT4H, and with disease onset in late adolescence/adulthood (one of them remaining asymptomatic at 20). On examination, foot deformity was observed without weakness or sensory involvement, and in the muscles of the lower extremities magnetic resonance imaging showed no fat replacement. Further analysis of FGD4 expression in peripheral blood suggested that neither mutation affected splicing, nor did they affect the dosage of FGD4 mRNA (compared to a healthy control). It was predicted that each allele would produce a truncated protein, p.Ala172Glnfs*28 (c.514delG) and p.Ala738Serfs*5 (c.2211dupA), the latter containing all the functional domains of the native protein. CONCLUSIONS The conservation of functional domains in the proteins produced from the FGD4 gene of two patients with CMT4H, could explain both the milder phenotype and the later disease onset in these patients. These results expand the clinical and mutational spectrum of FGD4-related peripheral neuropathies.
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Affiliation(s)
- Herminia Argente-Escrig
- Health Research Institute Hospital La Fe (IIS La Fe), Department of Neurology of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain.
| | - Ana Sánchez-Monteagudo
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain.
| | - Marina Frasquet
- Health Research Institute Hospital La Fe (IIS La Fe), Department of Neurology of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain.
| | - Elvira Millet-Sancho
- Department of Clinical Neurophysiology of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain.
| | - Maria Dolores Martínez-Rubio
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain.
| | - Inmaculada Pitarch
- Department of Paediatrics of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain.
| | - Miguel Tomás
- Department of Paediatrics of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain.
| | - Carmen Espinós
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain; Department of Genomics and Translational Genetics, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain; INCLIVA & IIS-La Fe Rare Diseases Joint Units, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain.
| | - Vincenzo Lupo
- Unit of Genetics and Genomics of Neuromuscular and Neurodegenerative Disorders, Centro de Investigación Príncipe Felipe (CIPF), 46012, Valencia, Spain; Department of Genomics and Translational Genetics, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain; INCLIVA & IIS-La Fe Rare Diseases Joint Units, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain.
| | - Teresa Sevilla
- Health Research Institute Hospital La Fe (IIS La Fe), Department of Neurology of the Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Spain; Department of Medicine, School of Medicine, University of Valencia, 46010, Valencia, Spain.
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14
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Novel GDAP1 Mutation in a Vietnamese Family with Charcot-Marie-Tooth Disease. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7132494. [PMID: 31179332 PMCID: PMC6507255 DOI: 10.1155/2019/7132494] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/21/2018] [Accepted: 04/14/2019] [Indexed: 01/09/2023]
Abstract
Background Mutations of GDAP1 gene cause autosomal dominant and autosomal recessive Charcot-Marie-Tooth (CMT) disease and over 80 different mutations have been identified so far. This study analyzed the clinical and genetic characteristics of a Vietnamese CMT family that was affected by a novel GDAP1 mutation. Methods We present three children of a family with progressive weakness, mild sensory loss, and absent tendon reflexes. Electrodiagnostic analyses displayed an axonal type of neuropathy in affected patients. Sequencing of GDAP1 gene was requested for all members of the family. Results All affected individuals manifested identical clinical symptoms of motor and sensory impairments within the first three years of life, and nerve conduction study indicated the axonal degeneration. A homozygous GDAP1 variant (c.667_671dup) was found in the three affected children as recessive inheritance pattern. The mutation leads to a premature termination codon that shortens GDAP1 protein (p.Gln224Hisfs∗37). Further testing showed heterozygous c.667_671dup variant in the parents. Discussion Our study expands the mutational spectrum of GDAP1-related CMT disease with the new and unreported GDAP1 variant. Alterations in GDAP1 gene should be evaluated as CMT causing variants in the Vietnamese population, predominantly axonal form of neuropathy in CMT disease.
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15
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Laššuthová P, Vill K, Erdem-Ozdamar S, Schröder JM, Topaloglu H, Horvath R, Müller-Felber W, Bansagi B, Schlotter-Weigel B, Gläser D, Neupauerová J, Sedláčková L, Staněk D, Mazanec R, Weis J, Seeman P, Senderek J. Novel SBF2 mutations and clinical spectrum of Charcot-Marie-Tooth neuropathy type 4B2. Clin Genet 2018; 94:467-472. [PMID: 30028002 DOI: 10.1111/cge.13417] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 07/04/2018] [Accepted: 07/17/2018] [Indexed: 12/27/2022]
Abstract
Biallelic SBF2 mutations cause Charcot-Marie-Tooth disease type 4B2 (CMT4B2), a sensorimotor neuropathy with autosomal recessive inheritance and association with glaucoma. Since the discovery of the gene mutation, only few additional patients have been reported. We identified seven CMT4B2 families with nine different SBF2 mutations. Revisiting genetic and clinical data from our cohort and the literature, SBF2 variants were private mutations, including exon-deletion and de novo variants. The neuropathy typically started in the first decade after normal early motor development, was predominantly motor and had a rather moderate course. Electrophysiology and nerve biopsies indicated demyelination and excess myelin outfoldings constituted a characteristic feature. While neuropathy was >90% penetrant at age 10 years, glaucoma was absent in ~40% of cases but sometimes developed with age. Consequently, SBF2 mutation analysis should not be restricted to individuals with coincident neuropathy and glaucoma, and CMT4B2 patients without glaucoma should be followed for increased intraocular pressure. The presence of exon-deletion and de novo mutations demands comprehensive mutation scanning and family studies to ensure appropriate diagnostic approaches and genetic counseling.
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Affiliation(s)
- P Laššuthová
- DNA Laboratory, Department of Pediatric Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - K Vill
- Department of Pediatric Neurology, Dr. v. Hauner Children's Hospital, LMU Munich, Munich, Germany
| | - S Erdem-Ozdamar
- Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - J M Schröder
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - H Topaloglu
- Department of Pediatric Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | - R Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - W Müller-Felber
- Department of Pediatric Neurology, Dr. v. Hauner Children's Hospital, LMU Munich, Munich, Germany
| | - B Bansagi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - B Schlotter-Weigel
- Friedrich-Baur-Institute, Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - D Gläser
- Genetikum, Center for Human Genetics, Neu-Ulm, Germany
| | - J Neupauerová
- DNA Laboratory, Department of Pediatric Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - L Sedláčková
- DNA Laboratory, Department of Pediatric Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - D Staněk
- DNA Laboratory, Department of Pediatric Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - R Mazanec
- Department of Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - J Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - P Seeman
- DNA Laboratory, Department of Pediatric Neurology, Charles University and University Hospital Motol, Prague, Czech Republic
| | - J Senderek
- Friedrich-Baur-Institute, Department of Neurology, University Hospital, LMU Munich, Munich, Germany
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16
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You Y, Wang X, Li S, Zhao X, Zhang X. Exome sequencing reveals a novel MFN2 missense mutation in a Chinese family with Charcot-Marie-Tooth type 2A. Exp Ther Med 2018; 16:2281-2286. [PMID: 30210586 PMCID: PMC6122517 DOI: 10.3892/etm.2018.6513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/08/2018] [Indexed: 12/20/2022] Open
Abstract
Charcot-Marie-Tooth (CMT) is a group of inherited peripheral neuropathies. To date, mutations in >80 genes are reportedly associated with CMT. Protein mitofusin 2 encoded by MFN2 serves an essential role in mitochondrial fusion and regulation of apoptosis, which has previously been reported to be highly associated with an axonal form of neuropathy (CMT2A). In the present study, a large Chinese family with severe CMT was reported and a genetic analysis of the disease was performed. A detailed physical examination for CMT was performed in 13 family members and electrophysiological examinations were performed in 3 affected family members. Whole-exome sequencing was performed on the proband, and the suspected variants were identified by Sanger sequencing. The pathogenicity of mutation was verified by restriction fragment length polymorphism analysis in the family followed by a bioinformatics analysis. A novel c.1190G>C; p.(R397P) mutation in the MFN2 gene was identified in the proband, and co-segregated between genotype and phenotype in the family. The substituted amino acid changed the hydrophobicity and charge characteristics of the mitofusin 2 coiled-coiled domain; thus it may affect its biological function. In summary, a novel pathogenic mutation was identified in a Chinese family with CMT, which expands the phenotypic and mutational spectrum of CMT2A, and provides evidence for prenatal interventions and more precise pharmacological treatments to this family.
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Affiliation(s)
- Yi You
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, P.R. China
| | - Xiaodong Wang
- Department of Paediatric Orthopaedics, The Children's Hospital of Soochow University, Suzhou, Jiangsu 215000, P.R. China
| | - Shan Li
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, P.R. China
| | - Xiuli Zhao
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, P.R. China
| | - Xue Zhang
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, P.R. China
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17
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Piscosquito G, Saveri P, Magri S, Ciano C, Gandioli C, Morbin M, Bella DD, Moroni I, Taroni F, Pareyson D. Screening for SH3TC2 gene mutations in a series of demyelinating recessive Charcot-Marie-Tooth disease (CMT4). J Peripher Nerv Syst 2018; 21:142-9. [PMID: 27231023 DOI: 10.1111/jns.12175] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/12/2016] [Accepted: 05/15/2016] [Indexed: 01/05/2023]
Abstract
Charcot-Marie-Tooth disease type 4C (CMT4C) is an autosomal recessive (AR) demyelinating neuropathy associated to SH3TC2 mutations, characterized by early onset, spine deformities, and cranial nerve involvement. We screened 43 CMT4 patients (36 index cases) with AR inheritance, demyelinating nerve conductions, and negative testing for PMP22 duplication, GJB1 and MPZ mutations, for SH3TC2 mutations. Twelve patients (11 index cases) had CMT4C as they carried homozygous or compound heterozygous mutations in SH3TC2. We found six mutations: three nonsense (p.R1109*, p.R954*, p.Q892*), one splice site (c.805+2T>C), one synonymous variant (p.K93K) predicting altered splicing, and one frameshift (p.F491Lfs*32) mutation. The splice site and the frameshift mutations are novel. Mean onset age was 7 years (range: 1-14). Neuropathy was moderate-to-severe. Scoliosis was present in 11 patients (severe in 4), and cranial nerve deficits in 9 (hearing loss in 7). Scoliosis and cranial nerve involvement are frequent features of this CMT4 subtype, and their presence should prompt the clinician to look for SH3TC2 gene mutations. In our series of undiagnosed CMT4 patients, SH3TC2 mutation frequency is 30%, confirming that CMT4C may be the most common AR-CMT type.
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Affiliation(s)
- Giuseppe Piscosquito
- Clinic of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Paola Saveri
- Clinic of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Stefania Magri
- Unit of Genetics of Neurodegenerative and Metabolic Disease, Department of Diagnostics and Applied Technology, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Claudia Ciano
- Neurophysiopathology and Epilepsy Centre, Department of Diagnostics and Applied Technology, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Claudia Gandioli
- Division of Child Neurology, Department of Pediatric Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Michela Morbin
- Division of Neurology and Neuropathology; Department of Diagnostics and Applied Technology, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Daniela D Bella
- Unit of Genetics of Neurodegenerative and Metabolic Disease, Department of Diagnostics and Applied Technology, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Isabella Moroni
- Division of Child Neurology, Department of Pediatric Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Franco Taroni
- Unit of Genetics of Neurodegenerative and Metabolic Disease, Department of Diagnostics and Applied Technology, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
| | - Davide Pareyson
- Clinic of Central and Peripheral Degenerative Neuropathies Unit, Department of Clinical Neurosciences, IRCCS Foundation, "C. Besta" Neurological Institute, Milan, Italy
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Pakhrin PS, Xie Y, Hu Z, Li X, Liu L, Huang S, Wang B, Yang Z, Zhang J, Liu X, Xia K, Tang B, Zhang R. Genotype–phenotype correlation and frequency of distribution in a cohort of Chinese Charcot–Marie–Tooth patients associated with GDAP1 mutations. J Neurol 2018; 265:637-646. [DOI: 10.1007/s00415-018-8743-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Revised: 12/13/2017] [Accepted: 01/07/2018] [Indexed: 01/08/2023]
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Abstract
This chapter reviews the diseases of the peripheral nerves from a neuropathologic point of view, with a special focus on specific morphologic changes, and includes a summary of the histopathologic methods available for their diagnosis. As the rate of obesity and the prevalence of type 2 diabetes increase, diabetic neuropathy is the most common cause of peripheral neuropathy. Many systemic disorders with metabolic origin, like amyloidosis, hepatic failure, vitamin deficiencies, uremia, lipid metabolism disorders, and others, can also cause axonal or myelin alterations in the peripheral nervous system. The most notable causes of toxic neuropathies are chemotherapeutic agents, alcohol consumption, and exposure to heavy metals and other environmental or biologic toxins. Inflammatory neuropathies cover infectious neuropathies (Lyme disease, human immunodeficiency virus, leprosy, hepatitis) and neuropathies of autoimmune origin (sarcoidosis, Guillain-Barré syndrome/acute inflammatory demyelinating polyneuropathy, chronic inflammatory demyelinating polyneuropathy, and diverse forms of vasculitis. The increasing number of known diseases causing gene mutations in hereditary peripheral neuropathies requires precise characterization, which includes histopathology.
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Peeters K, Chamova T, Tournev I, Jordanova A. Axonal neuropathy with neuromyotonia: there is a HINT. Brain 2017; 140:868-877. [PMID: 28007994 PMCID: PMC5382946 DOI: 10.1093/brain/aww301] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/08/2016] [Indexed: 02/06/2023] Open
Abstract
Recessive mutations in the gene encoding the histidine triad nucleotide binding protein 1 (HINT1) were recently shown to cause a motor-predominant Charcot–Marie–Tooth neuropathy. About 80% of the patients exhibit neuromyotonia, a striking clinical and electrophysiological hallmark that can help to distinguish this disease and to guide diagnostic screening. HINT1 neuropathy has worldwide distribution and is particularly prevalent in populations inhabiting central and south-eastern Europe. With 12 different mutations identified in more than 60 families, it ranks among the most common subtypes of axonal Charcot–Marie–Tooth neuropathy. This article provides an overview of the present knowledge on HINT1 neuropathy with the aim to increase awareness and spur interest among clinicians and researchers in the field. We propose diagnostic guidelines to recognize and differentiate this entity and suggest treatment strategies to manage common symptoms. As a recent player in the field of hereditary neuropathies, the role of HINT1 in peripheral nerves is unknown and the underlying disease mechanisms are unexplored. We provide a comprehensive overview of the structural and functional characteristics of the HINT1 protein that may guide further studies into the molecular aetiology and treatment strategies of this peculiar Charcot–Marie–Tooth subtype.
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Affiliation(s)
- Kristien Peeters
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB and University of Antwerp, Antwerpen 2610, Belgium
| | - Teodora Chamova
- Department of Neurology, Medical University-Sofia, Sofia 1431, Bulgaria
| | - Ivailo Tournev
- Department of Neurology, Medical University-Sofia, Sofia 1431, Bulgaria.,Department of Cognitive Science and Psychology, New Bulgarian University, Sofia 1618, Bulgaria
| | - Albena Jordanova
- Molecular Neurogenomics Group, Department of Molecular Genetics, VIB and University of Antwerp, Antwerpen 2610, Belgium.,Department of Medical Chemistry and Biochemistry, Molecular Medicine Center, Medical University-Sofia, Sofia 1431, Bulgaria
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Weis J, Claeys KG, Roos A, Azzedine H, Katona I, Schröder JM, Senderek J. Towards a functional pathology of hereditary neuropathies. Acta Neuropathol 2017; 133:493-515. [PMID: 27896434 DOI: 10.1007/s00401-016-1645-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 11/10/2016] [Accepted: 11/13/2016] [Indexed: 12/11/2022]
Abstract
A growing number of hereditary neuropathies have been assigned to causative gene defects in recent years. The study of human nerve biopsy samples has contributed substantially to the discovery of many of these neuropathy genes. Genotype-phenotype correlations based on peripheral nerve pathology have provided a comprehensive picture of the consequences of these mutations. Intriguingly, several gene defects lead to distinguishable lesion patterns that can be studied in nerve biopsies. These characteristic features include the loss of certain nerve fiber populations and a large spectrum of distinct structural changes of axons, Schwann cells and other components of peripheral nerves. In several instances the lesion patterns are directly or indirectly linked to the known functions of the mutated gene. The present review is designed to provide an overview on these characteristic patterns. It also considers other aspects important for the manifestation and pathology of hereditary neuropathies including the role of inflammation, effects of chemotherapeutic agents and alterations detectable in skin biopsies.
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Affiliation(s)
- Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany.
| | - Kristl G Claeys
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Department of Neurology, University Hospitals Leuven and University of Leuven (KU Leuven), Leuven, Belgium
| | - Andreas Roos
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Otto-Hahn-Str. 6b, 44227, Dortmund, Germany
| | - Hamid Azzedine
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Istvan Katona
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - J Michael Schröder
- Institute of Neuropathology, RWTH Aachen University Medical School, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Department of Neurology, Ludwig-Maximilians-University, Ziemssenstr. 1a, 80336, Munich, Germany.
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22
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Atkinson D, Nikodinovic Glumac J, Asselbergh B, Ermanoska B, Blocquel D, Steiner R, Estrada-Cuzcano A, Peeters K, Ooms T, De Vriendt E, Yang XL, Hornemann T, Milic Rasic V, Jordanova A. Sphingosine 1-phosphate lyase deficiency causes Charcot-Marie-Tooth neuropathy. Neurology 2017; 88:533-542. [PMID: 28077491 DOI: 10.1212/wnl.0000000000003595] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/16/2016] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To identify the unknown genetic cause in a nuclear family with an axonal form of peripheral neuropathy and atypical disease course. METHODS Detailed neurologic, electrophysiologic, and neuropathologic examinations of the patients were performed. Whole exome sequencing of both affected individuals was done. The effect of the identified sequence variations was investigated at cDNA and protein level in patient-derived lymphoblasts. The plasma sphingoid base profile was analyzed. Functional consequences of neuron-specific downregulation of the gene were studied in Drosophila. RESULTS Both patients present an atypical form of axonal peripheral neuropathy, characterized by acute or subacute onset and episodes of recurrent mononeuropathy. We identified compound heterozygous mutations cosegregating with disease and absent in controls in the SGPL1 gene, encoding sphingosine 1-phosphate lyase (SPL). The p.Ser361* mutation triggers nonsense-mediated mRNA decay. The missense p.Ile184Thr mutation causes partial protein degradation. The plasma levels of sphingosine 1-phosphate and sphingosine/sphinganine ratio were increased in the patients. Neuron-specific downregulation of the Drosophila orthologue impaired the morphology of the neuromuscular junction and caused progressive degeneration of the chemosensory neurons innervating the wing margin bristles. CONCLUSIONS We suggest SPL deficiency as a cause of a distinct form of Charcot-Marie-Tooth disease in humans, thus extending the currently recognized clinical and genetic spectrum of inherited peripheral neuropathies. Our data emphasize the importance of sphingolipid metabolism for neuronal function.
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Affiliation(s)
- Derek Atkinson
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Jelena Nikodinovic Glumac
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Bob Asselbergh
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Biljana Ermanoska
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - David Blocquel
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Regula Steiner
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Alejandro Estrada-Cuzcano
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Kristien Peeters
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Tinne Ooms
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Els De Vriendt
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Xiang-Lei Yang
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Thorsten Hornemann
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland
| | - Vedrana Milic Rasic
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland.
| | - Albena Jordanova
- From the Molecular Neurogenomics Group (D.A., B.E., A.E.-C., K.P., T.O., E.D.V., A.J.), VIB Department of Molecular Genetics (B.A.), University of Antwerp, Belgium; Clinic for Neurology and Psychiatry for Children and Youth (J.N.G), Belgrade, Serbia; Faculty of Medicine (V.M.R.), Clinic for Neurology and Psychiatry for Children and Youth, University of Belgrade, Serbia; Departments of Chemical Physiology and Cell and Molecular Biology (D.B., X.-L.Y.), The Scripps Research Institute, La Jolla, CA; and Institute of Clinical Chemistry (R.S., T.H.), University Hospital Zurich, University of Zurich, Switzerland.
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23
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Pedroso JL, Rocha CRR, Macedo-Souza LI, De Mario V, Marques W, Barsottini OGP, Bulle Oliveira AS, Menck CFM, Kok F. Mutation in PNKP presenting initially as axonal Charcot-Marie-Tooth disease. Neurol Genet 2015; 1:e30. [PMID: 27066567 PMCID: PMC4811384 DOI: 10.1212/nxg.0000000000000030] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 09/01/2015] [Indexed: 12/04/2022]
Abstract
PNKP (polynucleotide kinase 3'-phosphatase, OMIM #605610) product is involved in the repair of strand breaks and base damage in the DNA molecule mainly caused by radical oxygen species. Deleterious variants affecting this gene have been previously associated with microcephaly, epilepsy, and developmental delay.(1) According to a previous report, homozygous loss-of-function substitution in PNKP was associated with cerebellar atrophy, neuropathy, microcephaly, epilepsy, and intellectual disability.(2) Recently, whole-exome sequencing (WES) performed in a cohort of Portuguese families with ataxia with oculomotor apraxia (AOA) disclosed pathogenic variants in PNKP in 11 individuals. Other clinical features in that study included neuropathy, dystonia, cognitive impairment, decreased vibration sense, pyramidal signs, mild elevation in α-fetoprotein, and low levels of albumin. This condition was named AOA type 4 (OMIM #616267), as the phenotype of AOA has been previously associated with 3 other genes: APTX, SETX, and PIK3R5.(3) Altogether, these reports demonstrate the great phenotypic diversity associated with PNKP mutations. In this article, we further enlarge this variability by demonstrating that early-onset axonal sensory-motor neuropathy (or axonal Charcot-Marie-Tooth (CMT) disease) followed years later by ataxia without oculomotor apraxia can be caused by deleterious variants in PNKP. Full consent was obtained from the patient and his parents for this publication. This study was approved by institutional ethics committees.
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Affiliation(s)
- José Luiz Pedroso
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Clarissa R R Rocha
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Lucia I Macedo-Souza
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Vitor De Mario
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Wilson Marques
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Orlando G P Barsottini
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Acary S Bulle Oliveira
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Carlos F M Menck
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
| | - Fernando Kok
- Department of Neurology (J.L.P., O.G.P.B., A.S.B.O.), Federal University of São Paulo, São Paulo, Brazil; Department of Microbiology (C.R.R.R., C.F.M.M.), Institute of Biomedical Sciences, and Center for Human Genome and Stem Cell Research (L.I.M.-S., F.K.), Institute of Biosciences, University of São Paulo, São Paulo, Brazil; Mendelics Genomic Analysis (V.D.M., F.K.), São Paulo, Brazil; Department of Neurology (W.M.), University of São Paulo School of Medicine, Ribeirão Preto, Brazil; and Department of Neurology (F.K.), University of São Paulo School of Medicine, São Paulo, Brazil
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24
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Novel mutations in genes causing hereditary spastic paraplegia and Charcot-Marie-Tooth neuropathy identified by an optimized protocol for homozygosity mapping based on whole-exome sequencing. Genet Med 2015; 18:600-7. [PMID: 26492578 DOI: 10.1038/gim.2015.139] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 08/25/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Homozygosity mapping is an effective approach for detecting molecular defects in consanguineous families by delineating stretches of genomic DNA that are identical by descent. Constant developments in next-generation sequencing created possibilities to combine whole-exome sequencing (WES) and homozygosity mapping in a single step. METHODS Basic optimization of homozygosity mapping parameters was performed in a group of families with autosomal-recessive (AR) mutations for which both single-nucleotide polymorphism (SNP) array and WES data were available. We varied the criteria for SNP extraction and PLINK thresholds to estimate their effect on the accuracy of homozygosity mapping based on WES. RESULTS Our protocol showed high specificity and sensitivity for homozygosity detection and facilitated the identification of novel mutations in GAN, GBA2, and ZFYVE26 in four families affected by hereditary spastic paraplegia or Charcot-Marie-Tooth disease. Filtering and mapping with optimized parameters was integrated into the HOMWES (homozygosity mapping based on WES analysis) tool in the GenomeComb package for genomic data analysis. CONCLUSION We present recommendations for detection of homozygous regions based on WES data and a bioinformatics tool for their identification, which can be widely applied for studying AR disorders.Genet Med 18 6, 600-607.
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25
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Hyun YS, Lee J, Kim HJ, Hong YB, Koo H, Smith AST, Kim DH, Choi BO, Chung KW. Charcot-Marie-Tooth Disease Type 4H Resulting from Compound Heterozygous Mutations in FGD4 from Nonconsanguineous Korean Families. Ann Hum Genet 2015; 79:460-9. [PMID: 26400421 DOI: 10.1111/ahg.12134] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 07/03/2015] [Indexed: 01/06/2023]
Abstract
Charcot-Marie-Tooth disease type 4H (CMT4H) is an autosomal recessive demyelinating subtype of peripheral enuropathies caused by mutations in the FGD4 gene. Most CMT4H patients are in consanguineous Mediterranean families characterized by early onset and slow progression. We identified two CMT4H patients from a Korean CMT cohort, and performed a detailed genetic and clinical analysis in both cases. Both patients from nonconsanguineous families showed characteristic clinical manifestations of CMT4H including early onset, scoliosis, areflexia, and slow disease progression. Exome sequencing revealed novel compound heterozygous mutations in FGD4 as the underlying cause in both families (p.Arg468Gln and c.1512-2A>C in FC73, p.Met345Thr and c.2043+1G>A (p.Trp663Trpfs*30) in FC646). The missense mutations were located in highly conserved RhoGEF and PH domains which were predicted to be pathogenic in nature by in silico modeling. The CMT4H occurrence frequency was calculated to 0.7% in the Korean demyelinating CMT patients. This study is the first report of CMT4H in Korea. FGD4 assay could be considered as a means of molecular diagnosis for sporadic cases of demyelinating CMT with slow progression.
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Affiliation(s)
- Young Se Hyun
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Jinho Lee
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Hye Jin Kim
- Department of Biological Sciences, Kongju National University, Gongju, Korea
| | - Young Bin Hong
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Heasoo Koo
- Department of Pathology, Ewha Womans University School of Medicine, Seoul, Korea
| | - Alec S T Smith
- Department of Bioengineering, University of Washington, WA, USA
| | - Deok-Ho Kim
- Department of Bioengineering, University of Washington, WA, USA
| | - Byung-Ok Choi
- Department of Neurology, Sungkyunkwan University School of Medicine, Seoul, Korea.,Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Ki Wha Chung
- Department of Biological Sciences, Kongju National University, Gongju, Korea
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Mathis S, Goizet C, Tazir M, Magdelaine C, Lia AS, Magy L, Vallat JM. Charcot-Marie-Tooth diseases: an update and some new proposals for the classification. J Med Genet 2015; 52:681-90. [PMID: 26246519 DOI: 10.1136/jmedgenet-2015-103272] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/13/2015] [Indexed: 11/03/2022]
Abstract
BACKGROUND Charcot-Marie-Tooth (CMT) disease, the most frequent form of inherited neuropathy, is a genetically heterogeneous group of disorders of the peripheral nervous system, but with a quite homogeneous clinical phenotype (progressive distal muscle weakness and atrophy, foot deformities, distal sensory loss and usually decreased tendon reflexes). Our aim was to review the various CMT subtypes identified at the present time. METHODS We have analysed the medical literature and performed a historical retrospective of the main steps from the individualisation of the disease (at the end of the nineteenth century) to the recent knowledge about CMT. RESULTS To date, >60 genes (expressed in Schwann cells and neurons) have been implicated in CMT and related syndromes. The recent advances in molecular genetic techniques (such as next-generation sequencing) are promising in CMT, but it is still useful to recognise some specific clinical or pathological signs that enable us to validate genetic results. In this review, we discuss the diagnostic approaches and the underlying molecular pathogenesis. CONCLUSIONS We suggest a modification of the current classification and explain why such a change is needed.
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Affiliation(s)
- Stéphane Mathis
- Department of Neurology, University Hospital, Poitiers, France Department of Neurology (National Reference Center "Neuropathies Périphériques Rares"), University Hospital Dupuytren, Limoges, France
| | - Cyril Goizet
- Department of Medical Genetics, University Hospital (CHU Pellegrin), Bordeaux, France
| | - Meriem Tazir
- Department of Neurology, University Hospital Mustapha Bacha, Algiers, Algeria
| | | | - Anne-Sophie Lia
- Department of Genetics, University Hospital, Limoges, France
| | - Laurent Magy
- Department of Neurology (National Reference Center "Neuropathies Périphériques Rares"), University Hospital Dupuytren, Limoges, France
| | - Jean-Michel Vallat
- Department of Neurology (National Reference Center "Neuropathies Périphériques Rares"), University Hospital Dupuytren, Limoges, France
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Rudnik-Schöneborn S, Tölle D, Senderek J, Eggermann K, Elbracht M, Kornak U, von der Hagen M, Kirschner J, Leube B, Müller-Felber W, Schara U, von Au K, Wieczorek D, Bußmann C, Zerres K. Diagnostic algorithms in Charcot-Marie-Tooth neuropathies: experiences from a German genetic laboratory on the basis of 1206 index patients. Clin Genet 2015; 89:34-43. [PMID: 25850958 DOI: 10.1111/cge.12594] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 03/18/2015] [Accepted: 04/02/2015] [Indexed: 11/30/2022]
Abstract
We present clinical features and genetic results of 1206 index patients and 124 affected relatives who were referred for genetic testing of Charcot-Marie-Tooth (CMT) neuropathy at the laboratory in Aachen between 2001 and 2012. Genetic detection rates were 56% in demyelinating CMT (71% of autosomal dominant (AD) CMT1/CMTX), and 17% in axonal CMT (24% of AD CMT2/CMTX). Three genetic defects (PMP22 duplication/deletion, GJB1/Cx32 or MPZ/P0 mutation) were responsible for 89.3% of demyelinating CMT index patients in whom a genetic diagnosis was achieved, and the diagnostic yield of the three main genetic defects in axonal CMT (GJB1/Cx32, MFN2, MPZ/P0 mutations) was 84.2%. De novo mutations were detected in 1.3% of PMP22 duplication, 25% of MPZ/P0, and none in GJB1/Cx32. Motor nerve conduction velocity was uniformly <38 m/s in median or ulnar nerves in PMP22 duplication, >40 m/s in MFN2, and more variable in GJB1/Cx32, MPZ/P0 mutations. Patients with CMT2A showed a broad clinical severity regardless of the type or position of the MFN2 mutation. Out of 75 patients, 8 patients (11%) with PMP22 deletions were categorized as CMT1 or CMT2. Diagnostic algorithms are still useful for cost-efficient mutation detection and for the interpretation of large-scale genetic data made available by next generation sequencing strategies.
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Affiliation(s)
- S Rudnik-Schöneborn
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany
| | - D Tölle
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany
| | - J Senderek
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany.,Friedrich-Baur-Institute, LMU Munich, Munich, Germany
| | - K Eggermann
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany
| | - M Elbracht
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany
| | - U Kornak
- Institute of Medical Genetics and Human Genetics, Charité-University Berlin, Berlin, Germany
| | - M von der Hagen
- Abteilung Neuropädiatrie, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - J Kirschner
- Department of Neuropediatrics, University Hospital Freiburg, Freiburg, Germany
| | - B Leube
- Medical Faculty, Institute of Human Genetics and Anthropology, Heinrich-Heine University, Düsseldorf, Germany
| | - W Müller-Felber
- Dr. v. Hauner Childrens Hospital, University of Munich, Munich, Germany
| | - U Schara
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Essen, Essen, Germany
| | - K von Au
- SPZ Pediatric Neurology, Charité University Berlin, Berlin, Germany
| | - D Wieczorek
- Institute of Human Genetics, University Essen, Essen, Germany
| | - C Bußmann
- Center for Children and Adolescent Medicine, University Clinic Heidelberg, Heidelberg, Germany
| | - K Zerres
- Institute of Human Genetics, RWTH Aachen University Hospital, Aachen, Germany
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