Neurological complications of COVID-19 in hospitalized patients: The registry of a neurology department in the first wave of the pandemic.

OBJECTIVE: To describe the spectrum of neurological complications observed in a hospital-based cohort of COVID-19 patients who required a neurological assessment. METHODS: We conducted an observational, monocentric, prospective study of patients with a COVID-19 diagnosis hospitalized during the 3-month period of the first wave of the COVID-19 pandemic in a tertiary hospital in Madrid (Spain). We describe the neurological diagnoses that arose after the onset of COVID-19 symptoms. These diagnoses could be divided into different groups. RESULTS: Only 71 (2.6%) of 2750 hospitalized patients suffered at least one neurological complication (77 different neurological diagnoses in total) during the timeframe of the study. The most common diagnoses were neuromuscular disorders (33.7%), cerebrovascular diseases (CVDs) (27.3%), acute encephalopathy (19.4%), seizures (7.8%), and miscellanea (11.6%) comprising hiccups, myoclonic tremor, Horner syndrome and transverse myelitis. CVDs and encephalopathy were common in the early phase of the COVID-19 pandemic compared to neuromuscular disorders, which usually appeared later on (p = 0.005). Cerebrospinal fluid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) polymerase chain reaction was negative in 15/15 samples. The mortality was higher in the CVD group (38.1% vs. 8.9%; p = 0.05). CONCLUSIONS: The prevalence of neurological complications is low in patients hospitalized for COVID-19. Different mechanisms appear to be involved in these complications, and there was no evidence of direct invasion of the nervous system in our cohort. Some of the neurological complications can be classified into early and late neurological complications of COVID-19, as they occurred at different times following the onset of COVID-19 symptoms.

Immunoserologic Detection and Diagnostic Relevance of Cross-Reactive Autoantibodies in Coronavirus Disease 2019 Patients.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, we detected a new immunofluorescence (IF) pattern in serum autoantibody (autoAb) screening of laboratory-confirmed COVID-19 patients. METHODS: The IF pattern was composed of liver and gastric mucosa staining on rat kidney/liver/stomach sections. RESULTS: We describe 12 patients positive for the cross-reactive antibody, compared with a negative group of 43 hospitalized COVID-19 patients, finding association with either neurologic or thrombotic complications. In sequential pre- and post-COVID-19 serum samples, we confirmed autoAb seroconversion. CONCLUSIONS: Our data indicate that autoAb screening in COVID-19 patients may be easily performed by IF and alert for autoreactive-mediated complications such as thrombotic or neurologic events.

Altered Secretome and ROS Production in Olfactory Mucosa Stem Cells Derived from Friedreich's Ataxia Patients.

Friedreich's ataxia is the most common hereditary ataxia for which there is no cure or approved treatment at present. However, therapeutic developments based on the understanding of pathological mechanisms underlying the disease have advanced considerably, with the implementation of cellular models that mimic the disease playing a crucial role. Human olfactory ecto-mesenchymal stem cells represent a novel model that could prove useful due to their accessibility and neurogenic capacity. Here, we isolated and cultured these stem cells from Friedreich´s ataxia patients and healthy donors, characterizing their phenotype and describing disease-specific features such as reduced cell viability, impaired aconitase activity, increased ROS production and the release of cytokines involved in neuroinflammation. Importantly, we observed a positive effect on patient-derived cells, when frataxin levels were restored, confirming the utility of this in vitro model to study the disease. This model will improve our understanding of Friedreich´s ataxia pathogenesis and will help in developing rationally designed therapeutic strategies.

Parkinsonism and spastic paraplegia type 7: Expanding the spectrum of mitochondrial Parkinsonism.

BACKGROUND: Pathogenic variants in the spastic paraplegia type 7 gene cause a complicated hereditary spastic paraplegia phenotype associated with classical features of mitochondrial diseases, including ataxia, progressive external ophthalmoplegia, and deletions of mitochondrial DNA. OBJECTIVES: To better characterize spastic paraplegia type 7 disease with a clinical, genetic, and functional analysis of a Spanish cohort of spastic paraplegia type 7 patients. METHODS: Genetic analysis was performed in patients suspecting hereditary spastic paraplegia and in 1 patient with parkinsonism and Pisa syndrome, through next-generation sequencing, whole-exome sequencing, targeted Sanger sequencing, and multiplex ligation-dependent probe analysis, and blood mitochondrial DNA levels determined by quantitative polymerase chain reaction. RESULTS: Thirty-five patients were found to carry homozygous or compound heterozygous pathogenic variants in the spastic paraplegia type 7 gene. Mean age at onset was 40 years (range, 12-63); 63% of spastic paraplegia type 7 patients were male, and three-quarters of all patients had at least one allele with the c.1529C>T (p.Ala510Val) mutation. Eighty percent of the cohort showed a complicated phenotype, combining ataxia and progressive external ophthalmoplegia (65% and 26%, respectively). Parkinsonism was observed in 21% of cases. Analysis of blood mitochondrial DNA indicated that both patients and carriers of spastic paraplegia type 7 pathogenic variants had markedly lower levels of mitochondrial DNA than control subjects (228 per haploid nuclear DNA vs. 176 vs. 573, respectively; P < 0.001). CONCLUSIONS: Parkinsonism is a frequent finding in spastic paraplegia type 7 patients. Spastic paraplegia type 7 pathogenic variants impair mitochondrial DNA homeostasis irrespective of the number of mutant alleles, type of variant, and patient or carrier status. Thus, spastic paraplegia type 7 supports mitochondrial DNA maintenance, and variants in the gene may cause parkinsonism owing to mitochondrial DNA abnormalities. Moreover, mitochondrial DNA blood analysis could be a useful biomarker to detect at risk families. © 2019 International Parkinson and Movement Disorder Society.

Analysis of known amyotrophic lateral sclerosis and frontotemporal dementia genes reveals a substantial genetic burden in patients manifesting both diseases not carrying the C9orf72 expansion mutation.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are part of a clinical, pathological and genetic continuum. OBJECTIVES: The purpose of the present study was to assess the mutation burden that is present in patients with concurrent ALS and FTD (ALS/FTD) not carrying the chromosome 9 open reading frame 72 (C9orf72) hexanucleotide repeat expansion, the most important genetic cause in both diseases. METHODS: From an initial group of 973 patients with ALS, we retrospectively selected those patients fulfilling diagnostic criteria of concomitant ALS and FTD lacking the repeat expansion mutation in C9orf72. Our final study group consisted of 54 patients clinically diagnosed with ALS/FTD (16 with available postmortem neuropathological diagnosis). Data from whole exome sequencing were used to screen for mutations in known ALS and/or FTD genes. RESULTS: We identified 11 patients carrying a probable pathogenic mutation, representing an overall mutation frequency of 20.4%. TBK1 was the most important genetic cause of ALS/FTD (n=5; 9.3%). The second most common mutated gene was SQSTM1, with three mutation carriers (one of them also harboured a TBK1 mutation). We also detected probable pathogenic genetic alterations in TAF15, VCP and TARDBP and possible pathogenic mutations in FIG4 and ERBB4. CONCLUSION: Our results indicate a high genetic burden underlying the co-occurrence of ALS and FTD and expand the phenotype associated with TAF15, FIG4 and ERBB4 to FTD. A systematic screening of ALS and FTD genes could be indicated in patients manifesting both diseases without the C9orf72 expansion mutation, regardless of family history of disease.

Characterization of the repeat expansion size in C9orf72 in amyotrophic lateral sclerosis and frontotemporal dementia.

Hexanucleotide repeat expansions within the C9orf72 gene are the most important genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The difficulty of developing a precise method to determine the expansion size has hampered the study of possible correlations between the hexanucleotide repeat number and clinical phenotype. Here we characterize, through a new non-radioactive Southern blot protocol, the expansion size range in a series of 38 ALS and 22 FTD heterozygous carriers of >30 copies of the repeat. Maximum, median and modal hexanucleotide repeat number were higher in ALS patients than in FTD patients (P< 0.05 in all comparisons). A higher median number of repeats correlated with a bigger range of repeat sizes (Spearman's ρ = 0.743, P = 1.05 × 10(-11)). We did not find any correlation between age of onset or disease duration with the repeat size in neither ALS nor FTD mutation carriers. Clinical presentation (bulbar or spinal) in ALS patients did not correlate either with the repeat length. We finally analyzed two families with affected and unaffected repeat expansion carriers, compared the size of the repeat expansion between two monozygotic (MZ) twins (one affected of ALS and the other unaffected), and examined the expansion size in two different tissues (cerebellum and peripheral blood) belonging to the same FTD patient. The results suggested that the length of the C9orf72 repeat varies between family members, including MZ twins, and among different tissues from the same individual.

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

A hexanucleotide repeat expansion in chromosome 9 open reading frame 72 (C9orf72) can cause amyotrophic lateral sclerosis (ALS) and/or frontotemporal dementia (FTD). We assessed its frequency in 781 sporadic ALS (sALS) and 155 familial ALS (fALS) cases, and in 248 Spanish controls. We tested the presence of the reported founder haplotype among mutation carriers and in 171 Ceph Europeans from Utah (CEU), 170 Yoruba Africans, 81 Han Chinese, and 85 Japanese subjects. The C9orf72 expansion was present in 27.1% of fALS and 3.2% of sALS. Mutation carriers showed lower age at onset (P = 0.04), shorter survival (P = 0.02), greater co-occurrence of FTD (P = 8.2 × 10(-5)), and more family history of ALS (P = 1.4 × 10(-20)), than noncarriers. No association between alleles within the normal range and the risk of ALS was found (P = 0.12). All 61 of the mutation carriers were tested and a patient carrying 28 hexanucleotide repeats presented with the founder haplotype. This haplotype was found in 5.6% Yoruba Africans, 8.9% CEU, 3.9% Japanese, and 1.6% Han Chinese chromosomes.

Long-term outcome in chronic inflammatory demyelinating polyneuropathy patients treated with intravenous immunoglobulin: a retrospective study.

INTRODUCTION: The objective of this retrospective study was to describe the short- and long-term patterns of IVIg use, safety, and response to treatment in patients with chronic inflammatory demyelinating polyneuropathy (CIDP). METHODS: Response to therapy was defined as an improvement of ≥ 1 point on the modified Rankin score at short- and mid-term visits. Patient status at long term was classified as remission, stability, or non-responder. RESULTS: Eighty-six patients were included; 60.5% responded at short term and 54.6% at mid-term. At long term, 25.6% of patients were in remission, 65.1% were stable, and 9.3% were non-responders. The only variable associated with remission was a better response during the first 6 months of follow-up. CONCLUSIONS: A significant percentage of patients did not require any additional drugs in the long term. This suggests that treatment effect or disease outcome may be stable over time, and treatment regimens should therefore be individualized to avoid overtreatment.

Spanish Pompe registry: Baseline characteristics of first 49 patients with adult onset of Pompe disease. / Registro español de la enfermedad de Pompe: análisis de los primeros 49 pacientes con enfermedad de Pompe del adulto.

INTRODUCTION AND OBJECTIVES: Pompe disease is a rare autosomal recessive disorder produced by a deficiency of acid maltase. This deficit produces an accumulation of glycogen in tissues. Clinically it is mainly characterized by limb girdle and respiratory muscle weakness. In 2013, we developed the Spanish Pompe Registry. The objective of this article was to analyse the characteristics of the first 49 patients and disclose the existence of this registry within the medical community. MATERIAL AND METHODS: An observational retrospective study was undertaken. We analysed the 49 patients included in the Spanish Registry of Pompe Disease from May 2013 to October 2018. RESULTS: Patients were visited at 7 different Spanish hospitals. Twenty-six patients were women and 23 were men. The average age at the time of the analysis was 47.2 years. Ten patients were asymptomatic. The mean age of onset of symptoms was 29, and low limb girdle weakness was the most frequent initial symptom. Of the patients, 49% had respiratory involvement, and 70.8% of them required non-invasive mechanical ventilation. The most common mutation found was IVS1-13T>G in 85.3% of the patients. All symptomatic patients received treatment with ERT. CONCLUSIONS: This registry allows us to know the clinical and genetic characteristics of adult patients with Pompe disease in Spain. Moreover, it can be the basis for future studies of natural history to understand the impact of ERT in the course of the disease.

Clinical guide for the diagnosis and follow-up of myotonic dystrophy type 1, MD1 or Steinert's disease. / Guía clínica para el diagnóstico y seguimiento de la distrofia miotónica tipo 1, DM1 o enfermedad de Steinert.

BACKGROUND AND OBJECTIVES: Steinert's disease or myotonic dystrophy type 1 (MD1), (OMIM 160900), is the most prevalent myopathy in adults. It is a multisystemic disorder with dysfunction of virtually all organs and tissues and a great phenotypical variability, which implies that it has to be addressed by different specialities with experience in the disease. The knowledge of the disease and its management has changed dramatically in recent years. This guide tries to establish recommendations for the diagnosis, prognosis, follow-up and treatment of the complications of MD1. MATERIAL AND METHODS: Consensus guide developed through a multidisciplinary approach with a systematic literature review. Neurologists, pulmonologists, cardiologists, endocrinologists, neuropaediatricians and geneticists have participated in the guide. RECOMMENDATIONS: The genetic diagnosis should quantify the number of CTG repetitions. MD1 patients need cardiac and respiratory lifetime follow-up. Before any surgery under general anaesthesia, a respiratory evaluation must be done. Dysphagia must be screened periodically. Genetic counselling must be offered to patients and relatives. CONCLUSION: MD1 is a multisystemic disease that requires specialised multidisciplinary follow-up.

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

Objective: To 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. Methods: This 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. Results: Twenty-five patients were included: 11 treated with protocol 4 + 2 (375 mg/m2/4 weeks, then monthly for 2 months), five treated with protocol 1 + 1 (two 1 g doses 2 weeks apart), and nine treated with protocol 4 (375 mg/m2/4 weeks). Mean follow-up was 5.0 years (SD 3.3). Relapse occurred in 18.2%, 80%, and 33.3%, and mean time to relapse was 3.5 (SD 1.5), 1.1 (SD 0.4), and 2.5 (SD 1.4) years, respectively. Based on Kaplan-Meier estimates, patients treated with protocol 4 + 2 had fewer and later relapses than patients treated with the other two protocols (log-rank test P = 0.0001). Patients treated with protocol 1 + 1 had a higher risk of relapse than patients treated with protocol 4 + 2 (HR 112.8, 95% CI, 5.7-2250.4, P = 0.002). Patients treated with protocol 4 showed a trend to a higher risk of relapse than those treated with protocol 4 + 2 (HR 9.2, 95% CI 0.9-91.8, P = 0.059). Interpretation: This study provides class IV evidence that the 4 + 2 rituximab protocol has a lower clinical relapse rate and produces a more durable response than the 1 + 1 and 4 protocols in patients with MuSK MG.

ALS: A bucket of genes, environment, metabolism and unknown ingredients.

The scientific scenario of amyotrophic lateral sclerosis (ALS) has dramatically changed since TDP-43 aggregates were discovered in 2006 as the main component of the neuronal inclusions seen in the disease, and more recently, when the implication of C9ORF72 expansion in familial and sporadic cases of ALS and frontotemporal dementia was confirmed. These discoveries have enlarged an extense list of genes implicated in different cellular processes such as RNA processing or autophagia among others and have broaden the putative molecular targets of the disease. Some of ALS-related genes such as TARDBP or SOD1 among others have important roles in the regulation of glucose and fatty acids metabolism, so that an impairment of fatty acids (FA) consumption and ketogenic deficits during exercise in ALS patients would connect the physiopathology with some of the more intriguing epidemiological traits of the disease. The current understanding of ALS as part of a continuum with other neurodegenerative diseases and a crossroads between genetic, neurometabolic and environmental factors represent a fascinating model of interaction that could be translated to other neurodegenerative diseases. In this review we summarize the most relevant data obtained in the ten last years and the key lines for future research in ALS.

Extracellular Volume Detects Amyloidotic Cardiomyopathy and Correlates With Neurological Impairment in Transthyretin-familial Amyloidosis.

INTRODUCTION AND OBJECTIVES: Cardiac involvement determines prognosis and treatment options in transthyretin-familial amyloidosis. Cardiac magnetic resonance T1 mapping techniques are useful to assess myocardial extracellular volume. This study hypothesized that myocardial extracellular volume allows identification of amyloidotic cardiomyopathy and correlates with the degree of neurological impairment in transthyretin-familial amyloidosis. METHODS: A total of 31 transthyretin-familial amyloidosis patients (19 mean age, 49 ± 12 years; 26 with the Val30Met mutation) underwent a T1 mapping cardiac magnetic resonance study and a neurological evaluation with Neuropathy Impairment Score of the Lower Limb score, Norfolk Quality of Life questionnaire, and Karnofsky index. RESULTS: Five patients had cardiac amyloidosis (all confirmed by 99mTc-DPD scintigraphy). Mean extracellular volume was increased in patients with cardiac amyloidosis (0.490 ± 0.131 vs 0.289 ± 0.035; P = .026). Extracellular volume correlated with age (R = 0.467; P = .008), N-terminal pro-B-type natriuretic peptide (RS = 0.846; P < .001), maximum wall thickness (R = 0.621; P < .001), left ventricular mass index (R = 0.685; P < .001), left ventricular ejection fraction (R = -0.378; P = .036), Neuropathy Impairment Score of the Lower Limb (RS = 0.604; P = .001), Norfolk Quality of Life questionnaire (RS = 0.529; P = .003) and Karnofsky index (RS= -0.517; P = .004). A cutoff value of extracellular volume of 0.357 was diagnostic of cardiac amyloidosis with 100% sensitivity and specificity (P < .001). Extracellular volume and N-terminal pro-B-type natriuretic peptide were the only cardiac parameters that significantly correlated with neurologic scores. CONCLUSIONS: Extracellular volume quantification allows identification of cardiac amyloidosis and correlates with the degree of neurological impairment in transthyretin-familial amyloidosis. This noninvasive technique could be a useful tool for early diagnosis of cardiac amyloidosis and to track cardiac and extracardiac amyloid disease.

NEK1 variants confer susceptibility to amyotrophic lateral sclerosis.

To identify genetic factors contributing to amyotrophic lateral sclerosis (ALS), we conducted whole-exome analyses of 1,022 index familial ALS (FALS) cases and 7,315 controls. In a new screening strategy, we performed gene-burden analyses trained with established ALS genes and identified a significant association between loss-of-function (LOF) NEK1 variants and FALS risk. Independently, autozygosity mapping for an isolated community in the Netherlands identified a NEK1 p.Arg261His variant as a candidate risk factor. Replication analyses of sporadic ALS (SALS) cases and independent control cohorts confirmed significant disease association for both p.Arg261His (10,589 samples analyzed) and NEK1 LOF variants (3,362 samples analyzed). In total, we observed NEK1 risk variants in nearly 3% of ALS cases. NEK1 has been linked to several cellular functions, including cilia formation, DNA-damage response, microtubule stability, neuronal morphology and axonal polarity. Our results provide new and important insights into ALS etiopathogenesis and genetic etiology.

CCNF mutations in amyotrophic lateral sclerosis and frontotemporal dementia.

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are overlapping, fatal neurodegenerative disorders in which the molecular and pathogenic basis remains poorly understood. Ubiquitinated protein aggregates, of which TDP-43 is a major component, are a characteristic pathological feature of most ALS and FTD patients. Here we use genome-wide linkage analysis in a large ALS/FTD kindred to identify a novel disease locus on chromosome 16p13.3. Whole-exome sequencing identified a CCNF missense mutation at this locus. Interrogation of international cohorts identified additional novel CCNF variants in familial and sporadic ALS and FTD. Enrichment of rare protein-altering CCNF variants was evident in a large sporadic ALS replication cohort. CCNF encodes cyclin F, a component of an E3 ubiquitin-protein ligase complex (SCF(Cyclin F)). Expression of mutant CCNF in neuronal cells caused abnormal ubiquitination and accumulation of ubiquitinated proteins, including TDP-43 and a SCF(Cyclin F) substrate. This implicates common mechanisms, linked to protein homeostasis, underlying neuronal degeneration.

Kennedy disease with biphasic clinical course and rapid progression.

We report a case of spinal and bulbar muscular atrophy (SBMA), also known as Kennedy disease, with a 38 CAG-repeat expansion in exon-1 of the androgen receptor gene, presenting with a 2-year history of mild speech difficulty, dysphonia, and occasional choking. Initial clinical features and complementary studies were consistent with SBMA. The disease progression, as assessed by the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised, remained stable over the first 5 years from the onset but showed a rapid decline (from 42 to 24 points) over the next 18 months before his death. In the later stages of the disease, deep tendon reflexes were preserved in limbs and a brisk jaw-jerk reflex and bilateral Hoffmann sign were evident. Survival from disease onset was 78 months. The final cause of death was aspiration pneumonia. The atypical clinical features, evolution, and accelerated disease course are not concordant with the relatively short 38 CAG-repeat expansion in the androgen receptor gene. This may represent either a variant SBMA phenotype, which has not been recorded to date, or the development of amyotrophic lateral sclerosis in a known case of SBMA.

Exome-wide rare variant analysis identifies TUBA4A mutations associated with familial ALS.

Exome sequencing is an effective strategy for identifying human disease genes. However, this methodology is difficult in late-onset diseases where limited availability of DNA from informative family members prohibits comprehensive segregation analysis. To overcome this limitation, we performed an exome-wide rare variant burden analysis of 363 index cases with familial ALS (FALS). The results revealed an excess of patient variants within TUBA4A, the gene encoding the Tubulin, Alpha 4A protein. Analysis of a further 272 FALS cases and 5,510 internal controls confirmed the overrepresentation as statistically significant and replicable. Functional analyses revealed that TUBA4A mutants destabilize the microtubule network, diminishing its repolymerization capability. These results further emphasize the role of cytoskeletal defects in ALS and demonstrate the power of gene-based rare variant analyses in situations where causal genes cannot be identified through traditional segregation analysis.