Assessing Chitinases and Neurofilament Light Chain as Biomarkers for Adult-Onset Leukodystrophies.

Leukodystrophies represent a large and complex group of inherited disorders affecting the white matter of the central nervous system. Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a rare leukodystrophy which still needs the proper identification of diagnostic, prognostic, and monitoring biomarkers. The aim of this study was to determine the diagnostic and prognostic value of chitinases and neurofilament light chain as biomarkers for ALSP. A cross-sectional study was performed to analyze cerebrospinal fluid levels of chitinases (chitotriosidase and chitinase 3-like 2) and neurofilament light chain in five different groups: (i) normal health individuals; (ii) patients with definitive diagnosis of ALSP and genetic confirmation; (iii) asymptomatic patients with CSF1R variants; (iv) patients with other adult-onset leukodystrophies; and (v) patients with amyotrophic lateral sclerosis (external control group). Chitinase levels showed a statistical correlation with clinical assessment parameters in ALSP patients. Chitinase levels were also distinct between ALSP and the other leukodystrophies. Significant differences were noted in the levels of chitinases and neurofilament light chain comparing symptomatic (ALSP) and asymptomatic individuals with CSF1R variants. This study is the first to establish chitinases as a potential biomarker for ALSP and confirms neurofilament light chain as a good biomarker for primary microgliopathies.

GBE1-related disorders: Adult polyglucosan body disease and its neuromuscular phenotypes.

Adult polyglucosan body disease (APBD) represents a complex autosomal recessive inherited neurometabolic disorder due to homozygous or compound heterozygous pathogenic variants in GBE1 gene, resulting in deficiency of glycogen-branching enzyme and secondary storage of glycogen in the form of polyglucosan bodies, involving the skeletal muscle, diaphragm, peripheral nerve (including autonomic fibers), brain white matter, spinal cord, nerve roots, cerebellum, brainstem and to a lesser extent heart, lung, kidney, and liver cells. The diversity of new clinical presentations regarding neuromuscular involvement is astonishing and transformed APBD in a key differential diagnosis of completely different clinical conditions, including axonal and demyelinating sensorimotor polyneuropathy, progressive spastic paraparesis, motor neuronopathy presentations, autonomic disturbances, leukodystrophies or even pure myopathic involvement with limb-girdle pattern of weakness. This review article aims to summarize the main clinical, biochemical, genetic, and diagnostic aspects regarding APBD with special focus on neuromuscular presentations.

Neurofilament light chain as a biomarker for acute hepatic porphyrias.

Background: Acute hepatic porphyrias (AHP) represent a rare group of inherited metabolic disorders of heme biosynthesis pathway. This study aims to determine the diagnostic and prognostic value of serum neurofilament light chain (NfL) as potential biomarker for AHP. Methods: We conducted a cross-sectional observational study to evaluate NfL levels in patients with AHP. They were divided in different groups: normal health individuals; patients with definitive diagnosis of AHP during acute episodes; patients with AHP and infrequent attacks; patients with AHP and recurrent attacks; asymptomatic individuals with positive genetic testing and urinary delta-aminolevulinic acid (ALA) and porphobilinogen (PBG) levels elevated 4 or more times ("high excretors"); asymptomatic individuals with exclusive positive genetic test; control group with Hereditary Amyloidosis related to Transthyretin with Polyneuropathy (ATTRv-PN). Results: During acute attacks, serum NfL levels were 68 times higher compared to normal controls and disclosed a strong correlation with ALA and PBG levels; also exhibited elevated levels in patients with chronic symptoms regardless of the number of disease attacks compared to healthy controls, and at similar levels to patients with ATTRv-PN, which is a model of progressive neuropathy. Conclusion: This study represents the first to establish NfL as a biomarker for AHP, disclosing NfL as a sensitive biomarker for axonal damage and chronic symptom occurrence. This study not only underscores that neurological damage associated with the disease in any patient, irrespective of the number of attacks, but also reinforces the progressive and profoundly debilitating nature of acute and chronic symptoms observed in individuals with AHP.

Clinical and Genetic Aspects of Juvenile Amyotrophic Lateral Sclerosis: A Promising Era Emerges.

Juvenile Amyotrophic Lateral Sclerosis is a genetically heterogeneous neurodegenerative disorder, which is frequently misdiagnosed due to low clinical suspicion and little knowledge about disease characteristics. More than 20 different genetic loci have been associated with both sporadic and familial juvenile Amyotrophic Lateral Sclerosis. Currently, almost 40% of cases have an identifiable monogenic basis; type 6, associated with FUS gene variants, is the most prevalent globally. Despite several upper motor neuron-dominant forms being generally associated with long-standing motor symptoms and slowly progressive course, certain subtypes with lower motor neuron-dominant features and early bulbar compromise lead to rapidly progressive motor handicap. For some monogenic forms, there is a well-established genotypic-phenotypic correlation. There are no specific biochemical and neuroimaging biomarkers for the diagnosis of juvenile Amyotrophic Lateral Sclerosis. There are several inherited neurodegenerative and neurometabolic disorders which can lead to the signs of motor neuron impairment. This review emphasizes the importance of high clinical suspicion, assessment, and proper diagnostic work-up for juvenile Amyotrophic Lateral Sclerosis.

Clinical and Genetic Aspects of Childhood-Onset Demyelinating Charcot-Marie-Tooth's Disease in Brazil.

Charcot-Marie-Tooth's disease (CMT) represents the most common inherited neuropathy. Most patients are diagnosed during late stages of disease course during adulthood. We performed a review of clinical, neurophysiological, and genetic diagnoses of 32 patients with genetically defined childhood-onset demyelinating CMT under clinical follow-up in a Brazilian Center for Neuromuscular Diseases from January 2015 to December 2019. The current mean age was 33.1 ± 18.3 years (ranging from 7 to 71 years) and mean age at defined genetic diagnosis was 36.1 ± 18.3 years. The mean age at onset was 6.1 ± 4.4 years. The most common initial complaint was bilateral pes cavus. The genetic basis included PMP22 duplication (CMT1A) ( n = 18), GJB1 (CMTX1) ( n = 5), MPZ (CMT1B) ( n = 3), FIG4 (CMT4J) ( n = 3), SH3TC2 (CMT4C) ( n = 1), PLEKHG5 (CMTRIC) ( n = 1), and PRX (CMT4F) ( n = 1). Almost all patients ( n = 31) presented with moderate or severe compromise in the CMT neuropathy score 2 with the highest values observed in CMT1B. Medical history disclosed obstructive sleep apnea ( n = 5), aseptic meningitis ( n = 1/ MPZ ), akinetic-rigid parkinsonism ( n = 1/ FIG4 ), and overlapping chronic inflammatory demyelinating polyneuropathy ( n = 1/ MPZ ). Motor conduction block was detected in three individuals ( PMP22 , FIG4 , MPZ ). Acute denervation occurred in seven patients. Nonuniform demyelinating patterns were seen in four individuals (two CMT1A, one CMT1B, and one CMTX1). Abnormal cerebral white matter findings were detected in CMT1A and CMTX1, while hypertrophic roots were seen in CMT1A, CMT1B, and CMTX1. Our study emphasizes a relative oligogenic basis in childhood-onset demyelinating CMT and atypical findings may be observed especially in MPZ , PMP22 , and GJB1 gene variants.

Definitions, phenomenology, diagnosis, and management of the disorders of laughter and crying in amyotrophic lateral sclerosis (ALS): Consensus from ALS and Motor Neuron Disease Scientific Department of the Brazilian Academy of Neurology.

The spectrum of neuropsychiatric phenomena observed in amyotrophic lateral sclerosis (ALS) is wide and not fully understood. Disorders of laughter and crying stand among the most common manifestations. The aim of this study is to report the results of an educational consensus organized by the Brazilian Academy of Neurology to evaluate the definitions, phenomenology, diagnosis, and management of the disorders of laughter and crying in ALS patients. Twelve members of the Brazilian Academy of Neurology - considered to be experts in the field - were recruited to answer 12 questions about the subject. After exchanging revisions, a first draft was prepared. A face-to-face meeting was held in Fortaleza, Brazil on 9.23.22 to discuss it. The revised version was subsequently emailed to all members of the ALS Scientific Department from the Brazilian Academy of Neurology and the final revised version submitted for publication. The prevalence of pseudobulbar affect/pathological laughter and crying (PBA/PLC) in ALS patients from 15 combined studies and 3906 patients was 27.4% (N = 1070), ranging from 11.4% to 71%. Bulbar onset is a risk factor but there are limited studies evaluating the differences in prevalence among the different motor neuron diseases subtypes, including patients with and without frontotemporal dementia. Antidepressants and a combination of dextromethorphan and quinidine (not available in Brazil) are possible therapeutic options. This group of panelists acknowledge the multiple gaps in the current literature and reinforces the need for further studies.

O espectro de fenômenos neuropsiquiátricos observados na ELA é amplo e não completamente entendido. Desordens do riso e do choro estão entre as manifestações mais comuns. O objetivo deste estudo é relatar os resultados de um Consenso organizado pela Academia Brasileira de Neurologia para avaliar definições, fenomenologia, diagnóstico, e manejo dos distúrbios do riso e do choro em pacientes com ELA. Doze membros da Academia Brasileira de Neurologia ­ considerados experts na área ­ foram recrutados para responder 12 questões na temática. Depois da verificação das revisões, um primeiro manuscrito foi preparado. Após, foi realizado um encontro presencial em Fortaleza, Brasil, em 23/09/2022, para discussão do conteúdo. A versão revisada foi posteriormente enviada por e-mail para todos os membros do Departamento Científico de DNM/ELA da Academia Brasileira de Neurologia e a versão final revisada foi submetida para publicação. A prevalência da síndrome pseudobulbar em pacientes com ELA em 15 estudos combinados com 3906 pacientes foi de 27,4% (n = 1070), variando entre 11,4% e 71%. Início bulbar é um fator de risco, mas há limitados estudos avaliando as diferenças em prevalência entre os diferentes subtipos de Doença do Neurônio Motor, incluindo pacientes com e sem Demência Frontotemporal. Antidepressivos e uma combinação de dextrometorfana e quinidina (indisponíveis no Brasil) são opções terapêuticas possíveis. Esse grupo de panelistas reconhece as múltiplas demandas não atendidas na literatura atual e reforça a necessidade de futuros estudos.

The expanding clinical and genetic spectrum of alsin-related disorders: the first cohort of Brazilian patients.

There are three types of autosomal recessive disorders involving pathogenic variants in the ALS2 gene (OMIM*606352), infantile ascending hereditary spastic paraplegia (IAHSP), juvenile primary lateral sclerosis (JPLS) and juvenile amyotrophic lateral sclerosis (JALS), which are rare and related to retrograde degeneration of motor neurons. ALS2 pathogenic variants are distributed widely across the entire coding sequence and mostly result in a loss of protein function. Rarely, patients with JALS have been reported with lower motor neuron involvement. Here, we report the first Brazilian cohort (six patients) of JPLS with novel ALS2 pathogenic variants, and we propose an expanding clinical and genetic spectrum of alsin-related disorders. A review of the literature in PubMed from 2001 to September 2020 allowed us to identify 26 publications about the three different phenotypes caused by ALS2 variants (only case reports or families), encompassing 35 nonrelated families. We compiled data (sex, age, age at onset, first symptoms, atypical clinical features, molecular data, and clinical evolution (improvement or death)) from these studies and analyzed them in a general context on the basis of demographic features.

Cerebrotendinous Xanthomatosis: A practice review of pathophysiology, diagnosis, and treatment.

Cerebrotendinous Xanthomatosis represents a rare and underdiagnosed inherited neurometabolic disorder due to homozygous or compound heterozygous variants involving the CYP27A1 gene. This bile acid metabolism disorder represents a key potentially treatable neurogenetic condition due to the wide spectrum of neurological presentations in which it most commonly occurs. Cerebellar ataxia, peripheral neuropathy, spastic paraparesis, epilepsy, parkinsonism, cognitive decline, intellectual disability, and neuropsychiatric disturbances represent some of the most common neurological signs observed in this condition. Despite representing key features to increase diagnostic index suspicion, multisystemic involvement does not represent an obligatory feature and can also be under evaluated during diagnostic work-up. Chenodeoxycholic acid represents a well-known successful therapy for this inherited metabolic disease, however its unavailability in several contexts, high costs and common use in patients at late stages of disease course limit more favorable neurological outcomes for most individuals. This review article aims to discuss and highlight the most recent and updated knowledge regarding clinical, pathophysiological, neuroimaging, genetic and therapeutic aspects related to Cerebrotendinous Xanthomatosis.

Acute hepatic porphyrias for the neurologist: current concepts and perspectives.

BACKGROUND: Acute hepatic porphyrias represent an expanding group of complex inherited metabolic disorders due to inborn errors of metabolism involving heme biosynthesis. OBJECTIVE: We aimed to review the main clinical and therapeutic aspects associated with acute hepatic porphyrias. METHODS: The authors provided a wide non-systematic review of current concepts and recently acquired knowledge about acute hepatic porphyrias. RESULTS: Acute neurovisceral attacks are the most common and life-threatening presentation of this group and are often considered the main clinical manifestation by clinicians during differential diagnosis and the start of proper diagnostic work-up for acute porphyrias. However, atypical presentations with central nervous system involvement, neuropsychiatric disturbances, and some subtypes with photosensitivity usually make the definite diagnosis difficult and late. Early therapeutic interventions are essential during emergency treatment and intercritical periods to avoid recurrent severe presentations. The availability of new disease-modifying therapeutic proposals based on small interfering RNA (siRNA)-based therapies, complementary to the classic intravenous glucose infusion and hemin-based treatments, emphasizes the importance of early diagnosis and genetic counseling of patients. CONCLUSIONS: This review article highlights the main biochemical, pathophysiological, clinical, and therapeutic aspects of acute hepatic porphyrias in clinical practice.

Acute Hepatic Porphyria: Pathophysiological Basis of Neuromuscular Manifestations.

Acute hepatic porphyria represents a rare, underdiagnosed group of inherited metabolic disorders due to hereditary defects of heme group biosynthesis pathway. Most patients have their definite diagnosis after several years of complex and disabling clinical manifestations and commonly after life-threatening acute neurovisceral episodes or severe motor handicap. Many key studies in the last two decades have been performed and led to the discovery of novel possible diagnostic and prognostic biomarkers and to the development of new therapeutic purposes, including small interfering RNA-based therapy, specifically driven to inhibit selectively delta-aminolevulinic acid synthase production and decrease the recurrence number of severe acute presentation for most patients. Several distinct mechanisms have been identified to contribute to the several neuromuscular signs and symptoms. This review article aims to present the current knowledge regarding the main pathophysiological mechanisms involved with the acute and chronic presentation of acute hepatic porphyria and to highlight the relevance of such content for clinical practice and in decision making about therapeutic options.

Adult-onset non-5q proximal spinal muscular atrophy: a comprehensive review.

BACKGROUND: Adult-onset spinal muscular atrophy (SMA) represents an expanding group of inherited neurodegenerative disorders in clinical practice. OBJECTIVE: This review aims to synthesize the main clinical, genetic, radiological, biochemical, and neurophysiological aspects related to the classical and recently described forms of proximal SMA. METHODS: The authors performed a non-systematic critical review summarizing adult-onset proximal SMA presentations. RESULTS: Previously limited to cases of SMN1-related SMA type 4 (adult form), this group has now more than 15 different clinical conditions that have in common the symmetrical and progressive compromise of lower motor neurons starting in adulthood or elderly stage. New clinical and genetic subtypes of adult-onset proximal SMA have been recognized and are currently target of wide neuroradiological, pathological, and genetic studies. CONCLUSIONS: This new complex group of rare disorders typically present with lower motor neuron disease in association with other neurological or systemic signs of impairment, which are relatively specific and typical for each genetic subtype.

Progressive spastic tetraplegia and axial hypotonia (STAHP) due to SOD1 deficiency: is it really a new entity?

BACKGROUND: Amyotrophic Lateral Sclerosis (ALS) is a rare, progressive, and fatal neurodegenerative disease due to upper and lower motor neuron involvement with symptoms classically occurring in adulthood with an increasing recognition of juvenile presentations and childhood neurodegenerative disorders caused by genetic variants in genes related to Amyotrophic Lateral Sclerosis. The main objective of this study is detail clinical, radiological, neurophysiological, and genetic findings of a Brazilian cohort of patients with a recent described condition known as Spastic Tetraplegia and Axial Hypotonia (STAHP) due to SOD1 deficiency and compare with other cases described in the literature and discuss whether the clinical picture related to SOD1 protein deficiency is a new entity or may be represent a very early-onset form of Amyotrophic Lateral Sclerosis. METHODS: We conducted a case series report which included retrospective data from five Brazilian patients with SOD1 protein deficiency of a Brazilian reference center for Neuromuscular Disorders. Clinical data were obtained from a review of the medical records and descriptive statistics and variables were summarized using counts and percentages of the total population. RESULTS: All 5 patients presented with a childhood-onset neurodegenerative disorders characterized by spastic tetraplegia with axial hypotonia in all cases, with gestational history showing polyhydramnios in 4/5 and intrauterine growth restriction in 3/5 patients, with most patients initially presenting a normal motor development until the six month of life or during the first year followed by a rapidly progressive motor decline with severe dysphagia and respiratory insufficiency in all patients accompanied by cognitive impairment in 3/5 patients. All patients were homozygous for the c.335dupG (p.Cys112Trpfs*11) mutation in the SOD1 gene with completely decreased enzyme activity. CONCLUSIONS: This case series is the biggest data collection of the new recent clinical entity described as Spastic Tetraplegia and Axial Hypotonia (STAHP) due to SOD1 deficiency.

DRPLA: An unusual disease or an underestimated cause of ataxia in Brazil?

BACKGROUND: Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant spinocerebellar ataxia caused by pathological expansion of CAG trinucleotide repeats in the ATN1 gene. Most cases were described in patients from Japanese ancestry who presented with adult-onset progressive cerebellar ataxia associated with cognitive impairment, choreoathetosis and other movement disorders. DRPLA has been rarely described in Brazilian patients. METHODS: We performed a retrospective observational multicentric study including six different Neurology Centers in Brazil. All patients with genetically confirmed diagnosis of DRPLA had their medical records evaluated and clinical, genetic and neuroimaging features were analyzed. RESULTS: We describe of eight Brazilian patients (5 male, 3 female) from four nuclear families with genetically confirmed DRPLA. The most common neurological features included cerebellar ataxia (n = 7), dementia (n = 3), chorea (n = 2), psychiatric disturbances (n = 2), progressive myoclonic epilepsy (n = 2) and severe bulbar signs (n = 1). Progressive myoclonic epilepsy was observed in two juvenile-onset cases before 20-year. A large CAG trinucleotide length was observed in the two juvenile-onset cases and genetic anticipation was observed in all cases. Neuroimaging studies disclosed cerebellar atrophy (n = 6), as well as brainstem and cerebellar atrophy (n = 2) and leukoencephalopathy (n = 1). CONCLUSION: The patients described herein reinforce that clinical features of DRPLA are highly influenced by age of onset, genetic anticipation and CAG repetition lengths. There is a large complex spectrum of neurological features associated with DRPLA, varying from pure cerebellar ataxia to dementia associated with other movement disorders (myoclonus, choreoathetosis). DRPLA is an unusual cause of cerebellar ataxia and neurodegeneration in Brazilian patients.

Immunosuppressors and immunomodulators in Neurology - Part I: a guide for management of patients underimmunotherapy.

For patients with autoimmune diseases, the risks and benefits of immunosuppressive or immunomodulatory treatment are a matter of continual concern. Knowledge of the follow-up routine for each drug is crucial, in order to attain better outcomes and avoid new disease activity or occurrence of adverse effects. To achieve control of autoimmune diseases, immunosuppressive and immunomodulatory drugs act on different pathways of the immune response. Knowledge of the mechanisms of action of these drugs and their recommended doses, adverse reactions and risks of infection and malignancy is essential for safe treatment. Each drug has a specific safety profile, and management should be adapted for different circumstances during the treatment. Primary prophylaxis for opportunistic infections and vaccination are indispensable steps during the treatment plan, given that these prevent potential severe infectious complications. General neurologists frequently prescribe immunosuppressive and immunomodulatory drugs, and awareness of the characteristics of each drug is crucial for treatment success. Implementation of a routine before, during and after use of these drugs avoids treatment-related complications and enables superior disease control.

Intragenic variants in the SMN1 gene determine the clinical phenotype in 5q spinal muscular atrophy.

OBJECTIVE: The aim of the study was to report the proportion of homozygous and compound heterozygous variants in the survival motor neuron 1 (SMN1) gene in a large population of patients with spinal muscular atrophy (SMA) and to correlate the severity of the disease with the presence of specific intragenic variants in SMN1 and with the SMN2 copy number. METHODS: Four hundred fifty Brazilian patients with SMA were included in a retrospective study, and clinical data were analyzed compared with genetic data; the SMN2 copy number was obtained by multiplex ligation-dependent probe amplification and pathogenic variants in SMN1 by next-generation sequencing. RESULTS: Four hundred two patients (89.3%) presented homozygous exon 7-SMN1 deletion, and 48 (10.7%) were compound heterozygous for the common deletion in one allele and a point mutation in the other allele. Recurrent variants in exons 3 and 6 (c.460C>T, c.770_780dup and c.734_735insC) accounted for almost 80% of compound heterozygous patients. Another recurrent pathogenic variant was c.5C>G at exon 1. Patients with c.770_780dup and c.734_735insC had a clinical phenotype correlated with SMN2 copy number, whereas the variants c.460C>T and c.5C>G determined a milder phenotype independently of the SMN2 copies. CONCLUSIONS: Patients with specific pathogenic variants (c.460C>T and c.5C>G) presented a milder phenotype, and the SMN2 copy number did not correlate with disease severity in this group.

Reabilitação fisioterapêutica em pacientes com síndrome da pessoa rígida: revisão integrativa / Physiotherapy rehabilitation in patients with stiff person syndrome: integrative review

Introdução: A Síndrome da Pessoa Rígida é uma doença neuroimunológica rara do sistema nervoso central caracterizada por espasmos dolorosos e rigidez progressiva que envolvem os músculos proximais dos membros e axiais do tronco. A forma clássica tem início insidioso com piora gradual ao longo do tempo e muitas vezes leva à incapacidade permanente. Objetivo: Analisar os estudos publicados na literatura científica que utilizaram a reabilitação fisioterapêutica como proposta de tratamento dos sintomas motores na Síndrome da Pessoa Rígida. Método: Trata-se de uma revisão integrativa da literatura realizada no período de julho a dezembro de 2022 nas bases de dados PubMed, SciELO, LILACS e BVS. Resultados: Foram encontrados 12 artigos publicados entre o período de 2002 a 2021, que discorriam sobre o tratamento fisioterapêutico nesta população. O número escasso de estudos se dá pela raridade da patologia que dificulta a realização de ensaios clínicos robustos. Os artigos selecionados eram relatos de casos de um ou mais indivíduos, com enfoque nas intervenções realizadas de acordo com cada queixa funcional apresentada, sendo estas a dor, fraqueza muscular, hipomobilidade articular, rigidez, instabilidade postural, alterações na marcha e limitações nas atividades de vida diária. Conclusão: A reabilitação fisioterapêutica faz parte do tratamento sintomatológico e tem como finalidade, auxiliar na manutenção da funcionalidade e qualidade de vida, minimizando as repercussões motoras que são desencadeadas pela síndrome.

Introduction: Stiff Person Syndrome is a rare neuroimmunological disease of the central nervous system characterized by painful spasms and progressive rigidity involving the proximal muscles of the limbs and axial muscles of the trunk. The classic form has an insidious onset with gradual worsening over time and often leads to permanent disability. Objective: To analyze the studies published in the scientific literature that used hysiotherapeutic rehabilitation as a proposal for treating motor symptoms in Stiff Person Syndrome. Method: This is an integrative review of the literature carried out from July to December 2022 in the PubMed, SciELO, LILACS and VHL databases. Results: 12 articles published between 2002 and 2021 were found, which discussed physiotherapeutic treatment in this population. The scarce number of studies is due to the rarity of the pathology, which makes it difficult to carry out robust clinical trials. The selected articles were case reports of one or more individuals, focusing on interventions carried out according to each functional complaint presented, these being pain, muscle weakness, joint hypomobility, stiffness, postural instability, changes in gait and limitations in walking activities. daily life. Conclusion: Physiotherapy rehabilitation is part of symptomatological treatment and aims to help maintain functionality and quality of life, minimizing the motor repercussions that are triggered by the syndrome.