Assessment of Targeted Next-Generation Sequencing as a Tool for the Diagnosis of Charcot-Marie-Tooth Disease and Hereditary Motor Neuropathy

Charcot-Marie-Tooth disease is characterized by broad genetic heterogeneity with >50 known disease-associated genes. Mutations in some of these genes can cause a pure motor form of hereditary motor neuropathy, the genetics of which are poorly characterized. We designed a panel comprising 56 genes associated with Charcot-Marie-Tooth disease/hereditary motor neuropathy. We validated this diagnostic tool by first testing 11 patients with pathological mutations. A cohort of 33 affected subjects was selected for this study. The DNAJB2 c.352+1G>A mutation was detected in two cases; novel changes and/or variants with low frequency (50 known disease-associated genes. Mutations in some of these gene…

Clinical characteristics and outcomes of thymoma-associated myasthenia gravis

[Background and purpose] Prognosis of myasthenia gravis (MG) in patients with thymoma is not well established. Moreover, it is not clear whether thymoma recurrence or unresectable lesions entail a worse prognosis of MG.

The impact of rituximab infusion protocol on the long-term outcome in anti-MuSK myasthenia gravis

ObjectiveTo evaluate whether the clinical benefit and relapse rates in anti-muscle-specific kinase (MuSK) myasthenia gravis (MG) differ depending on the protocol of rituximab followed. MethodsThis retrospective multicentre study in patients with MuSK MG compared three rituximab protocols in terms of clinical status, relapse, changes in treatment, and adverse side effects. The primary effectiveness endpoint was clinical relapse requiring a further infusion of rituximab. Survival curves were estimated using Kaplan-Meier methods and survival analyses were undertaken using Cox proportional-hazards models. ResultsTwenty-five patients were included: 11 treated with protocol 4 + 2 (375 mg/m(2)/4 w…

The gene encoding ganglioside-induced differentiation-associated protein 1 is mutated in axonal Charcot-Marie-Tooth type 4A disease

We identified three distinct mutations and six mutant alleles in GDAP1 in three families with axonal Charcot-Marie-Tooth (CMT) neuropathy and vocal cord paresis, which were previously linked to the CMT4A locus on chromosome 8q21.1. These results establish the molecular etiology of CMT4A (MIM 214400) and suggest that it may be associated with both axonal and demyelinating phenotypes.

Lenalidomide induced reversible parkinsonism, dystonia, and dementia in subclinical Creutzfeldt-Jakob disease

Clinical spectrum of BICD2 mutations.

Background and purpose Mutations in the BICD2 gene cause autosomal dominant lower extremity-predominant spinal muscular atrophy 2A (SMALED2A), a condition that is associated with a specific pattern of thigh and calf muscle involvement when studied by magnetic resonance imaging (MRI). Patients may present minor clinical sensory impairment, but objective sensory involvement has yet to be demonstrated. Methods We collected clinical data from 11 patients from five different families carrying mutations in BICD2. Genetic diagnosis was achieved using gene panel testing and skin biopsies were taken from two patients to study the epidermal nerve fiber density. Results In the studied patients, three …

Clinical profile of motor neuron disease patients with lower urinary tract symptoms and neurogenic bladder

Introduction: Lower urinary tract symptoms (LUTS) are frequent in motor neuron disease (MND) patients, but clinical factors related to them are unknown. We describe differences in LUTS among MND phenotypes and their relationship with other clinical characteristics, including prognosis. Methods: For this study, we collected clinical data of a previously published cohort of patients diagnosed with classical amyotrophic lateral sclerosis (cALS), progressive muscular atrophy (PMA) or primary lateral sclerosis (PLS) with and without LUTS. Familial history was recorded and the C9ORF72 expansion was analysed in the entire cohort Patients were followed-up for survival until August 2016. Results: Fi…

Oxidative Stress, a Crossroad Between Rare Diseases and Neurodegeneration

Oxidative stress is an imbalance between production and accumulation of oxygen reactive species and/or reactive nitrogen species in cells and tissues, and the capacity of detoxifying these products, using enzymatic and non-enzymatic components, such as glutathione. Oxidative stress plays roles in several pathological processes in the nervous system, such as neurotoxicity, neuroinflammation, ischemic stroke, and neurodegeneration. The concepts of oxidative stress and rare diseases were formulated in the eighties, and since then, the link between them has not stopped growing. The present review aims to expand knowledge in the pathological processes associated with oxidative stress underlying …

Dejerine-Sottas neuropathy associated with De Novo S79P mutation of the peripheral myelin protein 22 (PMP22) gene

Drug‐refractory myasthenia gravis: Clinical characteristics, treatments, and outcome

[Objective] To describe the clinical characteristics and outcomes in patients with refractory myasthenia gravis (MG) and to determine the effectiveness and side effects of the drugs used for their treatment.

Junctophilin-1 is a modifier gene of GDAP1-related Charcot-Marie-Tooth disease.

Mutations in the GDAP1 gene cause different forms of Charcot-Marie-Tooth (CMT) disease, and the primary clinical expression of this disease is markedly variable in the dominant inheritance form (CMT type 2K; CMT2K), in which carriers of the GDAP1 p.R120W mutation can display a wide range of clinical severity. We investigated the JPH1 gene as a genetic modifier of clinical expression variability because junctophilin-1 (JPH1) is a good positional and functional candidate. We demonstrated that the JPH1-GDAP1 cluster forms a paralogon and is conserved in vertebrates. Moreover, both proteins play a role in Ca(2+) homeostasis, and we demonstrated that JPH1 is able to restore the store-operated Ca…

Vestibular impairment in Charcot-Marie-Tooth disease type 4C.

Charcot-Marie-Tooth disease type 4C (CMT4C) is a hereditary neuropathy with prominent unsteadiness. The objective of the current study is to determine whether the imbalance in CMT4C is caused only by reduced proprioceptive input or if vestibular nerve involvement is an additional factor. We selected 10 CMT4C patients and 10 age-matched and sex-matched controls. We performed a comprehensive evaluation of the vestibular system, including video Head Impulse Test, bithermal caloric test, galvanic stimulation test and skull vibration-induced nystagmus test. None of the patients experienced dizziness, spontaneous or gaze-evoked nystagmus, but all had significant vestibular impairment when tested …

Early Referral to an ALS Center Reduces Several Months the Diagnostic Delay: A Multicenter-Based Study.

Objective: To analyze those factors contributing to the diagnostic delay in ALS.Methods: Consecutive ALS patients were categorized as those studied in departmental hospitals and those studied in a referral ALS center. Demographic and clinical variables, together with data of the diagnostic pathway were collected. Multivariable models were used to assess their effect in the time between symptoms onset and the first neurologist visit (time symptoms-neurologist), in the time between the first neurologist visit and the diagnosis (time neurologist-diagnosis) and in the diagnostic delay.Results: 166 ALS patients with a median diagnostic delay of 11.53 months (IQR: 6.68, 15.23) were included. The …

Mutations in theMORC2gene cause axonal Charcot–Marie–Tooth disease

Charcot-Marie-Tooth disease (CMT) is a complex disorder with wide genetic heterogeneity. Here we present a new axonal Charcot-Marie-Tooth disease form, associated with the gene microrchidia family CW-type zinc finger 2 (MORC2). Whole-exome sequencing in a family with autosomal dominant segregation identified the novel MORC2 p.R190W change in four patients. Further mutational screening in our axonal Charcot-Marie-Tooth disease clinical series detected two additional sporadic cases, one patient who also carried the same MORC2 p.R190W mutation and another patient that harboured a MORC2 p.S25L mutation. Genetic and in silico studies strongly supported the pathogenicity of these sequence variant…

Validation of motor and functional scales for the evaluation of adult patients with 5q spinal muscular atrophy

ABSTRACTObjectiveTo assess in adult spinal muscular atrophy (SMA) patients the construct validity and responsiveness of several outcome measures.MethodsPatients older than 15 years and followed-up at least for 6 months, between October 2015 and August 2020, with one motor function scale (Hammersmith Functional Motor Scale Expanded, HFMSE; Revised Upper Limb module, RULM) in five referral centers were included. Bedside functional scales (Egen Klassification, EK2; Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, ALSFRS-R) were also collected when available. Correlations and regression models were performed to evaluate the construct validity. The monthly slopes of change were use…

Characterization of molecular mechanisms underlying the axonal Charcot–Marie–Tooth neuropathy caused by MORC2 mutations

Mutations in MORC2 lead to an axonal form of Charcot-Marie-Tooth (CMT) neuropathy type 2Z. To date, 31 families have been described with mutations in MORC2, indicating that this gene is frequently involved in axonal CMT cases. While the genetic data clearly establish the causative role of MORC2 in CMT2Z, the impact of its mutations on neuronal biology and their phenotypic consequences in patients remains to be clarified. We show that the full-length form of MORC2 is highly expressed in both embryonic and adult human neural tissues and that Morc2 expression is dynamically regulated in both the developing and the maturing murine nervous system. To determine the effect of the most common MORC2…

Phenotypical features of two patients diagnosed with PHARC syndrome and carriers of a new homozygous mutation in the ABHD12 gene.

Abstract PHARC (Polyneuropathy, Hearing loss, Ataxia, Retinitis pigmentosa and Cataracts) (MIM# 612674 ) is an autosomal recessive neurodegenerative disease caused by mutations in the ABHD12 gene. We evaluated two Spanish siblings affected with pes cavus, sensorimotor neuropathy, hearing loss, retinitis pigmentosa and juvenile cataracts in whom the genetic test of ABHD12 revealed a novel homozygous frameshift mutation, c.211_223del (p.Arg71Tyrfs*26). The earliest clinical manifestation in these patients was a demyelinating neuropathy manifested with a Charcot-Marie-Tooth phenotype over three decades. Progressive hearing loss, cataracts and retinitis pigmentosa appeared after the age of 30. …

Presenilin-1 Mutations Are a Cause of Primary Lateral Sclerosis-Like Syndrome

6 páginas, 2 figuras

Charcot-Marie-Tooth disease: Genetic and clinical spectrum in a Spanish clinical series

Objectives: To determine the genetic distribution and the phenotypic correlation of an extensive series of patients with Charcot-Marie-Tooth disease in a geographically well-defined Mediterranean area. Methods: A thorough genetic screening, including most of the known genes involved in this disease, was performed and analyzed in this longitudinal descriptive study. Clinical data were analyzed and compared among the genetic subgroups. Results: Molecular diagnosis was accomplished in 365 of 438 patients (83.3%), with a higher success rate in demyelinating forms of the disease. The CMT1A duplication (PMP22 gene) was the most frequent genetic diagnosis (50.4%), followed by mutations in the GJB1…

Phenotype and natural history of inherited neuropathies caused byHSJ1c.352+1G>A mutation

Mutations in the HSJ1 ( Heat-Shock Protein J1 ) gene, also called DNAJB2 (DnaJ (Hsp40) homologue, subfamily B, member 2), have been recently described as a cause of hereditary neuropathies. The HSJ1 c.352+1G>A mutation in homozygote state has been reported as the causative mutation in a single family with autosomal recessive distal hereditary motor neuropathy (dHMN).1 Since then, two other families with different HSJ1 mutations have been described: one with a dHMN phenotype and the other with a Charcot-Marie-Tooth disease type 2 (CMT2) phenotype.2 We identified the HSJ1 c.352+1G>A mutation in 10 patients who underwent long-lasting follow-up. We describe their phenotype and clinical evolutio…

Analysis of the C9orf72 gene in patients with amyotrophic lateral sclerosis in Spain and different populations worldwide.

The C9ORF72 Spanish Study Group, et al.

Clinical and neuroimaging characterization of two C9orf72-positive siblings with amyotrophic lateral sclerosis and schizophrenia

C9orf72 expansion is the main genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and has also been found in a wide spectrum of other neurodegenerative diseases (...

Longitudinally extensive transverse myelitis with AQP4 antibodies revealing ovarian teratoma.

Paraneoplastic myelitis is a rare inflammatory disorder most frequently associated with solid tumors or lymphoproliferative disorders. Patients often harbor onconeuronal antibodies and their prognosis is usually poor. Here we report a 42-year old woman with longitudinally extensive transverse myelitis and aquaporin-4 (AQP4) antibodies that led to the diagnosis of ovarian teratoma. After tumor removal and immune therapy (including corticosteroids, plasma exchange, intravenous immunoglobulins and rituximab) the patient progressively improved achieving complete recovery. Histological study of the teratoma demonstrated neural tissue containing AQP4 expressing cells and intense inflammatory infi…

IqYmune® is an effective maintenance treatment for multifocal motor neuropathy: A randomised, double‐blind, multi‐center cross‐over non‐inferiority study vs Kiovig®—The LIME Study

Intravenous immunoglobulin (IVIg) is the gold-standard for maintenance treatment of multifocal motor neuropathy (MMN). This phase III, randomised, double-blind, multi-centre, active-control, crossover study, aimed to evaluate the non-inferiority of IqYmune® relative to Kiovig®, primarily based on efficacy criteria. Twenty-two adult MMN patients, treated with any brand of IVIg (except Kiovig® or IqYmune®) at a stable maintenance dose within the range of 1 to 2 g/kg every 4 to 8 weeks, were randomised to receive either Kiovig® followed by IqYmune®, or IqYmune® followed by Kiovig®. Each product was administered for 24 weeks. The primary endpoint was the difference between IqYmune® and Kiovig® …

Clinical and therapeutic features of myasthenia gravis in adults based on age at onset

[Objective] To describe the characteristics of patients with very-late-onset myasthenia gravis (MG).

Distribution and genotype-phenotype correlation of GDAP1 mutations in Spain

AbstractMutations in the GDAP1 gene can cause Charcot-Marie-Tooth disease. These mutations are quite rare in most Western countries but not so in certain regions of Spain or other Mediterranean countries. This cross-sectional retrospective multicenter study analyzed the clinical and genetic characteristics of patients with GDAP1 mutations across Spain. 99 patients were identified, which were distributed across most of Spain, but especially in the Northwest and Mediterranean regions. The most common genotypes were p.R120W (in 81% of patients with autosomal dominant inheritance) and p.Q163X (in 73% of autosomal recessive patients). Patients with recessively inherited mutations had a more seve…

Netrin-1 receptor antibodies in thymoma-associated neuromyotonia with myasthenia gravis.

Objective:To identify cell-surface antibodies in patients with neuromyotonia and to describe the main clinical implications.Methods:Sera of 3 patients with thymoma-associated neuromyotonia and myasthenia gravis were used to immunoprecipitate and characterize neuronal cell-surface antigens using reported techniques. The clinical significance of antibodies against precipitated proteins was assessed with sera of 98 patients (neuromyotonia 46, myasthenia gravis 52, thymoma 42; 33 of them with overlapping syndromes) and 219 controls (other neurologic diseases, cancer, and healthy volunteers).Results:Immunoprecipitation studies identified 3 targets, including the Netrin-1 receptors DCC (deleted i…

Nusinersen in adult patients with 5q spinal muscular atrophy: a multicenter observational cohorts’ study

ABSTRACTObjectiveTo assess safety and efficacy of nusinersen in adult 5q spinal muscular atrophy (SMA) patients.MethodsPatients older than 15 years and followed at least for 6 months with one motor scale (Hammersmith Functional Motor Scale Expanded, HFMSE; Revised Upper Limb module, RULM) in five referral centers were included. Clinical and patients’ global impression of change (CGI-C and PGI-C) were recorded in treated patients at the last visit. Functional scales (Egen Klassification, EK2; Revised Amyotrophic Lateral Sclerosis Functional Rating Scale, ALSFRS-R) and the percent-predicted forced vital capacity were collected when available.ResultsSeventy-nine SMA patients (39 treated with n…

Clinical and genetic characteristics of 21 Spanish patients with biallelic pathogenic SPG7 mutations.

Spastic paraplegia type 7 (SPG7) is one of the most common hereditary spastic paraplegias. SPG7 mutations most often lead to spastic paraparesis (HSP) and/or hereditary cerebellar ataxia (HCA), frequently with mixed phenotypes. We sought to clinically and genetically characterize a Spanish cohort of SPG7 patients. Patients were recruited from our HCA and HSP cohorts. We identified twenty-one patients with biallelic pathogenic SPG7 mutations. Mean age at onset was 37.4 years (SD ± 14.3). The most frequent phenotype was spastic ataxia (57%), followed by pure spastic paraplegia (19%) and complex phenotypes (19%). Isolated patients presented with focal or multifocal dystonia, subclinical myopat…

The EGR2 gene is involved in axonal Charcot-Marie-Tooth disease

Background and purpose A three-generation family affected by axonal Charcot−Marie−Tooth disease (CMT) was investigated with the aim of discovering genetic defects and to further characterize the phenotype. Methods The clinical, nerve conduction studies and muscle magnetic resonance images of the patients were reviewed. A whole exome sequencing was performed and the changes were investigated by genetic studies, in silico analysis and luciferase reporter assays. Results A novel c.1226G>A change (p.R409Q) in the EGR2 gene was identified. Patients presented with a typical, late-onset axonal CMT phenotype with variable severity that was confirmed in the ancillary tests. The in silico studies sho…

A very mild phenotype of Charcot-Marie-Tooth disease type 4H caused by two novel mutations in FGD4

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 i…

Genetics of the Charcot-Marie-Tooth disease in the Spanish Gypsy population: the hereditary motor and sensory neuropathy-Russe in depth

Four private mutations responsible for three forms demyelinating of Charcot-Marie-Tooth (CMT) or hereditary motor and sensory neuropathy (HMSN) have been associated with the Gypsy population: the NDRG1 p.R148X in CMT type 4D (CMT4D/HMSN-Lom); p.C737_P738delinsX and p.R1109X mutations in the SH3TC2 gene (CMT4C); and a G>C change in a novel alternative untranslated exon in the HK1 gene causative of CMT4G (CMT4G/HMSN-Russe). Here we address the findings of a genetic study of 29 Gypsy Spanish families with autosomal recessive demyelinating CMT. The most frequent form is CMT4C (57.14%), followed by HMSN-Russe (25%) and HMSN-Lom (17.86%). The relevant frequency of HMSN-Russe has allowed us to inv…

Patient-reported impact of Charcot-Marie-Tooth disease: protocol for a real-world digital lifestyle study

Abstract Background Charcot-Marie-Tooth disease (CMT) is a rare, chronic, progressive motor and sensory neuropathy that affects the peripheral nervous system, leading to progressive, predominantly distal muscle weakness, atrophy, sensory loss and progressive limb dysfunction. As with many rare diseases, there is a lack of patient-reported data with which to understand and address patient needs. This study aims to explore the real-world impact of CMT from the patient perspective. Methods This is a prospective, digital lifestyle study of at least 2,000 people with CMT, >18 years, resident in the following countries: France, Germany, Italy, Spain, the UK and the USA. Participants will be re…

Generation of a disease-specific iPS cell line derived from a patient with Charcot-Marie-Tooth type 2K lacking functional GDAP1 gene

Human CMT2-FiPS4F1 cell line was generated from fibroblasts of a patient with Charcot-Marie-Tooth disease harbouring the following mutations in the GDAP1 gene in heterozygosis: p.Q163X/p.T288NfsX3. This patient did not present mutations in the PM22, MPZ or GJB genes. Human reprogramming factors OCT3/4, KLF4, SOX2 and C-MYC were delivered using a non-integrative methodology that involves the use of Sendai virus.

Infections of the Central Nervous System after Unrelated Donor Umbilical Cord Blood Transplantation or Human Leukocyte Antigen–Matched Sibling Transplantation

We analyzed the incidence, clinical characteristics, prognostic factors, and outcome of central nervous system (CNS) infections in consecutive patients with receiving umbilical cord blood transplantation (UCBT) (n = 343) or HLA-matched sibling donor stem cell transplantation (MST) (n = 366). Thirty-four CNS infections were documented at a median time of 116 days after transplantation (range, 7 to 1161). The cumulative incidence (CI) risk of developing a CNS infection was .6% at day +30, 2.3% at day +90, and 4.9% at 5 years. The 5-year CI of CNS infection was 8.2% after UCBT and 1.7% after MST (P  .001). The causative micro-organisms of CNS infections were fungi (35%), virus (32%), Toxoplasm…

Genetic and constitutional factors are major contributors to substantia nigra hyperechogenicity

9 páginas, 2 figuras, 4 tablas