Efficacy of Exome-Targeted Capture Sequencing to Detect Mutations in Known Cerebellar Ataxia Genes.

Importance: Molecular diagnosis is difficult to achieve in disease groups with a highly heterogeneous genetic background, such as cerebellar ataxia (CA). In many patients, candidate gene sequencing or focused resequencing arrays do not allow investigators to reach a genetic conclusion.

Objectives: To assess the efficacy of exome-targeted capture sequencing to detect mutations in genes broadly linked to CA in a large cohort of undiagnosed patients and to investigate their prevalence.

Fluxomic assay-assisted diagnosis orientation in a cohort of 11 patients with myopathic form of CPT2 deficiency.

Carnitine palmitoyltransferase type 2 (CPT2) deficiency, a mitochondrial fatty acid oxidation disorder (MFAOD), is a cause of myopathy in its late clinical presentation. As for other MFAODs, its diagnosis may be evocated when blood acylcarnitine profile is abnormal. However, a lack of abnormalities or specificity in this profile is not exclusive of CPT2 deficiency.

Pathogenesis of cranial neuropathies in Moebius syndrome: Electrodiagnostic orofacial studies.

Introduction: We designed a retrospective study of 59 patients with congenital sporadic nonprogressive bilateral facial and abducens palsies.

Methods: Examinations included needle electromyography (EMG) of facial and oral muscles, facial nerve motor latency and conduction velocity (FNCV), and blink responses (BR).

Results: Neurogenic EMG changes were found in 1 or more muscles in 55 of 59 patients, with no abnormal spontaneous activity.

Development and Validation of a New Scoring System to Predict Survival in Patients With Myotonic Dystrophy Type 1.

Importance: Life expectancy is greatly shortened in patients presenting with myotonic dystrophy type 1 (DM1), the most common neuromuscular disease. A reliable prediction of survival in patients with DM1 is critically important to plan personalized health supervision.

Objective: To develop and validate a prognostic score to predict 10-year survival in patients with DM1.

Downregulation of myostatin pathway in neuromuscular diseases may explain challenges of anti-myostatin therapeutic approaches.

Muscular dystrophies are characterized by weakness and wasting of skeletal muscle tissues. Several drugs targeting the myostatin pathway have been used in clinical trials to increase muscle mass and function but most showed limited efficacy. Here we show that the expression of components of the myostatin signaling pathway is downregulated in muscle wasting or atrophying diseases, with a decrease of myostatin and activin receptor, and an increase of the myostatin antagonist, follistatin.

Mutations in GFPT1-related congenital myasthenic syndromes are associated with synaptic morphological defects and underlie a tubular aggregate myopathy with synaptopathy.

Mutations in GFPT1 (glutamine-fructose-6-phosphate transaminase 1), a gene encoding an enzyme involved in glycosylation of ubiquitous proteins, cause a limb-girdle congenital myasthenic syndrome (LG-CMS) with tubular aggregates (TAs) characterized predominantly by affection of the proximal skeletal muscles and presence of highly organized and remodeled sarcoplasmic tubules in patients' muscle biopsies. We report here the first long-term clinical follow-up of 11 French individuals suffering from LG-CMS with TAs due to GFPT1 mutations, of which nine are new. Our retrospective clinical evaluation stresses an evolution toward a myopathic weakness that occurs concomitantly to ineffectiveness of usual CMS treatments.

Effect of enzyme replacement therapy with alglucosidase alfa (Myozyme®) in 12 patients with advanced late-onset Pompe disease.

Background: The efficacy of enzyme replacement therapy (ERT) in patients at an advanced stage of Pompe disease has only been addressed in a few studies. Our objective was to assess the long term effects of ERT in a cohort of patients with severe Pompe disease.

Methods: We identified patients from the French Pompe Registry with severe respiratory failure and permanent wheelchair use (assisted walk for a few meters was allowed) when starting ERT.

Inflammatory myopathies: A new landscape.

Greater accuracy in clinical descriptions combined with advances in muscle histology and immunology have established that inflammatory myopathies (IMs), similarly to inflammatory rheumatic diseases, constitute a highly heterogeneous group of conditions. The topographic distribution, severity, and tempo of onset of the myopathy vary widely, and the histological findings distinguish at least five different profiles, which may reflect different pathophysiological processes. Most IMs are connective tissue diseases that can affect multiple organs, among which the most common targets are the skin, joints, and lungs.

Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients.

Background And Purpose: Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP).

Methods: Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey.

Incidence and predictors of sudden death, major conduction defects and sustained ventricular tachyarrhythmias in 1388 patients with myotonic dystrophy type 1.

Aims: To describe the incidence and identify predictors of sudden death (SD), major conduction defects and sustained ventricular tachyarrhythmias (VTA) in myotonic dystrophy type 1 (DM1).

Methods And Results: We retrospectively enrolled 1388 adults with DM1 referred to six French medical centres between January 2000 and October 2013. We confirmed their vital status, classified all deaths, and determined the incidence of major conduction defects requiring permanent pacing and sustained VTA.

Non Random Distribution of DMD Deletion Breakpoints and Implication of Double Strand Breaks Repair and Replication Error Repair Mechanisms.

Background: Dystrophinopathies are mostly caused by copy number variations, especially deletions, in the dystrophin gene (DMD). Despite the large size of the gene, deletions do not occur randomly but mainly in two hot spots, the main one involving exons 45 to 55. The underlying mechanisms are complex and implicate two main mechanisms: Non-homologous end joining (NHEJ) and micro-homology mediated replication-dependent recombination (MMRDR).

Contactin-Associated Protein 1 (CNTNAP1) Mutations Induce Characteristic Lesions of the Paranodal Region.

Congenital hypomyelinating neuropathy is a rare neonatal syndrome responsible for hypotonia and weakness. Nerve microscopic examination shows amyelination or hypomyelination. Recently, mutations in CNTNAP1 have been described in a few patients.

Pulmonary arterial hypertension in idiopathic inflammatory myopathies: Data from the French pulmonary hypertension registry and review of the literature.

Occurrence of pulmonary arterial hypertension (PAH) in idiopathic inflammatory myopathies (IIMs) without extensive interstitial lung disease (ILD) has rarely been described in the medical literature. This study aimed to report all cases with association of PAH and IIM in the French Pulmonary Hypertension (PH) Registry, to identify IIM features associated with the presence of PAH, and to describe treatment modalities of these patients.All cases of IIM-PAH were retrieved from the French PH Registry, which gathers PH patients prospectively enrolled by 27 referral hospital centers across France.

Impaired Presynaptic High-Affinity Choline Transporter Causes a Congenital Myasthenic Syndrome with Episodic Apnea.

The neuromuscular junction (NMJ) is one of the best-studied cholinergic synapses. Inherited defects of peripheral neurotransmission result in congenital myasthenic syndromes (CMSs), a clinically and genetically heterogeneous group of rare diseases with fluctuating fatigable muscle weakness as the clinical hallmark. Whole-exome sequencing and Sanger sequencing in six unrelated families identified compound heterozygous and homozygous mutations in SLC5A7 encoding the presynaptic sodium-dependent high-affinity choline transporter 1 (CHT), which is known to be mutated in one dominant form of distal motor neuronopathy (DHMN7A).

[Chronic fatigue syndrome: A new disorder?].

More than 30 years after its individualization, chronic fatigue syndrome (CFS) remains a debilitating condition for the patient and a confusing one to the physicians, both because of diagnostic difficulties and poorly codified management. Despite the numerous work carried out, its pathophysiology remains unclear, but a multifactorial origin is suggested with triggering (infections) and maintenance (psychological) factors as well as the persistence of inflammatory (low grade inflammation, microglial activation…), immunologic (decrease of NK cells, abnormal cytokine production, reactivity to a variety of allergens, role of estrogens…) and muscular (mitochondrial dysfunction and failure of bioenergetic performance) abnormalities at the origin of multiple dysfunctions (endocrine, neuromuscular, cardiovascular, digestive…). The complexity of the problem and the sometimes contradictory results of available studies performed so far are at the origin of different pathophysiological and diagnostic concepts.

Otopalatodigital spectrum disorders: refinement of the phenotypic and mutational spectrum.

Otopalatodigital spectrum disorders (OPDSD) constitute a group of dominant X-linked osteochondrodysplasias including four syndromes: otopalatodigital syndromes type 1 and type 2 (OPD1 and OPD2), frontometaphyseal dysplasia, and Melnick-Needles syndrome. These syndromes variably associate specific facial and extremities features, hearing loss, cleft palate, skeletal dysplasia and several malformations, and show important clinical overlap over the different entities. FLNA gain-of-function mutations were identified in these conditions.

Natural history of LGMD2A for delineating outcome measures in clinical trials.

Objective: Limb-girdle muscular dystophy 2A (LGMD2A, OMIM) is a slowly progressive myopathy caused by the deficiency in calpain 3, a calcium-dependent cysteine protease of the skeletal muscle.

Methods: In this study, we carried out an observational study of clinical manifestations and disease progression in genetically confirmed LGMD2A patients for up to 4 years. A total of 85 patients, aged 14-65 years, were recruited in three centers located in metropolitan France, the Basque country, and the Reunion Island.

Identifying a therapeutic window in acute and subacute inflammatory sensory neuronopathies.

Background: Patients with inflammatory sensory neuronopathy (SNN) may benefit from immunomodulatory or immunosuppressant treatments if administered timely. Knowing the temporal profile of neuronal loss in dorsal root ganglia will help to ascertain whether a final diagnosis may be reached before the occurrence of irreversible neuronal injuries. Thus, we addressed the evolution of neuronal loss in SNN by using sensory nerve action potentials (SNAPs) as a surrogate marker of neuron degeneration.

Expanding the clinical spectrum of hereditary fibrosing poikiloderma with tendon contractures, myopathy and pulmonary fibrosis due to FAM111B mutations.

Background: Hereditary Fibrosing Poikiloderma (HFP) with tendon contractures, myopathy and pulmonary fibrosis (POIKTMP [MIM 615704]) is a very recently described entity of syndromic inherited poikiloderma. Previously by using whole exome sequencing in five families, we identified the causative gene, FAM111B (NM_198947.3), the function of which is still unknown.

Delayed-onset Friedreich's ataxia revisited.

Background: Friedreich's ataxia usually occurs before the age of 25. Rare variants have been described, such as late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia, occurring after 25 and 40 years, respectively. We describe the clinical, functional, and molecular findings from a large series of late-onset Friedreich's ataxia and very-late-onset Friedreich's ataxia and compare them with typical-onset Friedreich's ataxia.