Spectrum of SPTLC1-related disorders: a novel case of 'Ser331 syndrome' that expand the phenotype of hereditary sensory and autonomic neuropathy type 1A and motor neuron diseases.

We report a patient with early-onset hereditary sensory and autonomic neuropathy type 1A (HSAN-1A) who developed a distinct phenotype, with tongue fasciculation and atrophy, due to a mutation at serine 331 in the SPTLC1 gene. HSAN-1A manifestation causing tongue fasciculation and atrophy have been rarely found. Our report adds to the growing evidence of the existence of an overlap between hereditary neuropathy and motor neuron disease caused by pathogenic p.S331Y variant in SPTLC1 gene.

Charcot-Marie-Tooth disease type 4C associated with myasthenia gravis: coincidental or a foreseeable association?

We reported one patient with Charcot-Marie-Tooth type 4C (CMT4C) who developed seropositive myasthenia gravis. Neuromuscular junction alterations in CMT4C patients have not yet been reported. However, few patients have been reported to simultaneously have MG and CMT, but none with CMT4C. Our report suggests that additional research is required to confirm whether genetic neuropathies may predispose to MG.

Predictors of early left ventricular systolic dysfunction in duchenne muscular dystrophy patients.

INTRODUCTION: Early detection of left ventricular systolic dysfunction (LVSD) is important for therapeutic strategies for Duchenne muscular dystrophy (DMD) patients. We analyzed myocardial strain using echocardiography for early detection of LVSD and determined the predictors of early LVSD. METHODS: This investigation was a cross-sectional study of 40 DMD patients with normal left ventricular ejection fraction. Global longitudinal strain (GLS) was used to analyze subtle disturbances in longitudinal contraction of the myocardium. Patients were determined to have early LVSD (GLS > -18) or normal left ventricular systolic function (GLS ≤ -18). RESULTS: Patients who had early LVSD were older and had a higher frequency of corticosteroid therapy and of mutations in exons 45, 46, 47, 48, 49, 50, and 52. DISCUSSION: Myocardial strain measurements are useful for the early diagnosis of LVSD in DMD patients. Older age, use of corticosteroids, and mutations within the "hot-spot" region of the DMD gene are associated with early LVSD. Muscle Nerve, 2018.

Triple-seronegative myasthenia gravis: clinical and epidemiological characteristics.

BACKGROUND: Myasthenia gravis (MG) is an autoimmune disease usually caused by antibodies against the acetylcholine receptor (AChR-Abs), muscle-specific tyrosine kinase (MuSK-Abs), or low-density lipoprotein receptor-related protein 4 (LRP4-Abs). However, there are MG patients who do not have these antibodies and are thus said to have triple-seronegative (triple-SN) MG. OBJECTIVE: This study aims to describe the frequency and clinical and epidemiological characteristics of patients with triple-SN MG. METHODS: This was a retrospective cross-sectional study carried out through the analysis of medical records. Descriptive and analytical statistical analysis was performed comparing subgroups of myasthenic patients, classified according to serological profile. RESULTS: The sample population consisted of 93 MG patients: 85 were positive for antibodies, 80 (86%) with AChR-Abs, 5 (5.4%) with MuSK-Abs, and no MG patients with LRP4-Abs. Eight patients (8.6%) had triple-SN MG; they had a median age at disease onset of 30 years (21-45). Their most common initial symptoms were ptosis, diplopia, and generalized weakness. Most patients presented with mild symptoms at their last visit, reflecting a median MG composite scale score of 4 (0-6), and 75% of patients had an adequate response to treatment. CONCLUSION: Our study showed a low frequency of triple-SN MG in Brazilian MG patients. Triple-SN MG was predominant in females, who presented with ptosis, diplopia, and generalized weakness, and most patients had an adequate response to immunosuppressive treatment. There was no significant difference between triple-SN MG and the other subgroups.

ANTECEDENTES: A Miastenia gravis (MG) é uma desordem autoimune geralmente causada por anticorpos antirreceptores de acetilcolina (anti-RACh), tirosina quinase músculo-específica (anti-MuSK) ou proteína 4 relacionada ao receptor de lipoproteína de baixa densidade (anti-LRP4). No entanto, em uma parcela dos pacientes, nenhum destes três anticorpos pôde ser detectado, sendo estes casos denominados "triplo-soronegativos". OBJETIVO: Descrever a frequência, bem como as características clínicas e epidemiológicas dos pacientes com MG triplo-soronegativa. MéTODOS: Consiste em um estudo transversal e restrospectivo, realizado através da análise de prontuários médicos. Foi realizada análise estatística descritiva e analítica entre os subgrupos de pacientes, classificados de acordo com o perfil sorológico. RESULTADOS: A população consistiu de 93 pacientes com MG: 85 pacientes apresentavam positividade para anticorpos, sendo 80 (86%) com anticorpos anti-RACh, cinco (5,4%) com anti-MuSK, e não foram encontrados pacientes com anti-LRP4. Oito (8,6%) eram pacientes triplo-soronegativos, que apresentaram idade média de início da doença de 30 anos (21-45), e com sintomas iniciais mais comuns de ptose, diplopia e fraqueza generalizada. 75% dos pacientes triplo-soronegativos apresentaram resposta adequada ao tratamento. CONCLUSãO: O estudo demonstrou uma baixa frequência da pacientes com MG triplo-soronegativa na população brasileira. A MG triplo-soronegativa foi predominante nas mulheres, que se apresentaram com ptose, diplopia ou fraqueza generalizada, e a maioria dos pacientes apresentou resposta adequada ao tratamento imunossupressor. Não houve diferença significativa entre a MG triplo-soronegativa e os demais subgrupos.

Myopathy due to carnitine palmitoyltransferase II deficiency: updating genetic aspects of the first publication in Brazil.

Carnitine palmitoyltransferase II (CPT II) deficiency is an autosomal recessive inherited disorder related to lipid metabolism affecting skeletal muscle. The first cases of CPT II deficiency causing myopathy were reported in 1973. In 1983, Werneck et al published the first two Brazilian patients with myopathy due to CPT II deficiency, where the biochemical analysis confirmed deficient CPT activity in the muscle of both cases. Over the past 40 years since the pioneering publication, clinical phenotypes and genetic loci in the CPT2 gene have been described, and pathogenic mechanisms have been better elucidated. Genetic analysis of one of the original cases disclosed compound heterozygous pathogenic variants (p.Ser113Leu/p.Pro50His) in the CPT2 gene. Our report highlights the historical aspects of the first Brazilian publication of the myopathic form of CPT II deficiency and updates the genetic background of this pioneering publication.

Deficiência de carnitina palmitoiltransferase II (CPT II) é uma desordem de herança autossômica recessiva relacionada com o metabolismo do lipídio afetando músculo esquelético. Os primeiros dois casos de deficiência de CPT II causando miopatia foram relatados em 1973. Em 1983, Werneck et al. publicaram os primeiros pacientes brasileiros com miopatia por deficiência de CPT II, nos quais a análise bioquímica confirmou a atividade deficiente da CPT nos músculos em ambos os casos. Após 40 anos desde a publicação pioneira, fenótipos clínicos e loci genético no gene CPT2 foram descritos, bem com os mecanismos patológicos foram melhor elucidados. A análise genética de um dos casos da publicação original apresentou variantes patogênicas em heterozigose composta (p.Ser113Leu/p.Pro50His) no gene CPT2. O nosso relato destaca os aspectos históricos da primeira publicação brasileira da forma miopática da deficiência de CPT II e atualiza as bases genéticas dessa publicação pioneira.

Single-centre experience with autosomal recessive limb-girdle muscular dystrophy: case series and literature review.

Limb-girdle muscular dystrophy (LGMD) is a group of myopathies that lead to progressive muscle weakness, predominantly involving the shoulder and pelvic girdles; it has a heterogeneous genetic etiology, with variation in the prevalence of subtypes according to the ethnic backgrounds and geographic origins of the populations. The aim of the present study was to analyze a series of patients with autosomal recessive LGMD (LGMD-R) to contribute to a better characterization of the disease and to find the relative proportion of the different subtypes in a Southern Brazil cohort. The sample population consisted of 36 patients with LGMD-R. A 9-gene targeted next-generation sequencing panel revealed variants in 23 patients with LGMD (64%), and it identified calpainopathy (LGMD-R1) in 26%, dysferlinopathy (LGMD-R2) in 26%, sarcoglycanopathies (LGMD-R3-R5) in 13%, telethoninopathy (LGMD-R7) in 18%, dystroglicanopathy (LGMD-R9) in 13%, and anoctaminopathy (LGMD-R12) in 4% of the patients. In these 23 patients with LGMD, there were 27 different disease-related variants in the ANO5, CAPN3, DYSF, FKRP, SGCA, SGCB, SGCG, and TCAP genes. There were different causal variants in different exons of these genes, except for the TCAP gene, for which all patients carried the p.Gln53* variant, and the FKRP gene, which showed recurrence of the p.Leu276Ile variant. We analyzed the phenotypic, genotypic and muscle immunohistochemical features of this Southern Brazilian cohort.

A distrofia muscular de cinturas (DMC) é um grupo de miopatias que leva à fraqueza muscular progressiva, e envolvendo predominante as cinturas escapular e pélvica. A DMCtem uma etiologia genética heterogênea, com variação na prevalência de subtipos de acordo com as origens étnicas e geográficas das populações. O objetivo deste estudo foi analisar uma série de pacientes com DMC do tipo autossômico recessivo (DMC-R) para contribuir para uma melhor caracterização da doença e encontrar a proporção relativa dos diferentes subtipos em uma coorte do Sul do Brasil. A população amostral foi composta por 36 pacientes com DMC-R. O painel de sequenciamento de nova geração com 9 genes revelou variantes em 23 pacientes com DMC (64%), e identificou calpainopatia (DMC-R1) em 26%, disferlinopatia (DMC-R2) em 26%, sarcoglicanopatias (DMC-R3­R5) em 13%, teletoninopatia (D-MCR7) em 18%, distroglicanopatia (D-MCR9) em 13%, e anoctaminopatia (DMC-R12) em 4% dos pacientes. Nesses 23 pacientes com DMC, havia 27 variantes diferentes nos genes ANO5, CAPN3, DYSF, FKRP, SGCA, SGCB, SGCG e TCAP. Foram encontradas diferentes variantes em diferentes éxons desses genes, com exceção do gene TCAP, para o qual todos os pacientes eram portadores da variante p.Gln53*, e do gene FKRP, que apresentou recorrência da variante p.Leu276Ile. As características fenotípicas, genotípicas e imuno-histoquímicas musculares desta coorte do Sul do Brasil foram analisadas.

Seventy years since the invention of the averaging technique in Neurophysiology: Tribute to George Duncan Dawson.

OBJECTIVE: In 1951, the physiologist George Duncan Dawson presented his work with the averaging of the signal in the evoked potentials (EPs), opening a new stage in the development of clinical neurophysiology. The authors present aspects of Professor Dawson's biography and a review of his work on the EPs and, mainly, the article reveals the new technique in detail that would allow the growth of the clinical application of the visual, auditory, and somatosensory EPs.

Congenital myasthenic syndrome in a cohort of patients with 'double' seronegative myasthenia gravis.

BACKGROUND: Congenital myasthenic syndromes (CMS) have some phenotypic overlap with seronegative myasthenia gravis (SNMG). OBJECTIVE: The aim of this single center study was to assess the minimum occurrence of CMS misdiagnosed as double SNMG in a Brazilian cohort. METHODS: The genetic analysis of the most common mutations in CHRNE, RAPSN, and DOK7 genes was used as the main screening tool. RESULTS: We performed genetic analysis in 22 patients with a previous diagnosis of 'double' SNMG. In this study, one CMS patient was confirmed due to the presence of compound heterozygous variants in the CHRNE gene (c.130insG/p.Cys210Phe). CONCLUSIONS: This study confirmed that CMS due to CHNRE mutations can be mistaken for SNMG. In addition, our study estimated the prevalence of misdiagnosed CMS to be 4.5% in 'double' SNMG patients of our center. Based on our findings, genetic screening could be helpful in the diagnostic workup of patients with 'double' SNMG in whom differential diagnosis is recommended.

Peripheral polyneuropathy from electrodiagnostic tests: a 10-year etiology and neurophysiology overview.

BACKGROUND: Polyneuropathies are characterized by a symmetrical impairment of the peripheral nervous system, resulting in sensory, motor and/or autonomic deficits. Due to the heterogeneity of causes, an etiological diagnosis for polyneuropathy is challenging. OBJECTIVE: The aim of this study was to determine the main causes of polyneuropathy confirmed by electrodiagnostic (EDX) tests in a tertiary service and its neurophysiological aspects. METHODS: This observational cross-sectional study from a neuromuscular disorders center included individuals whose electrodiagnostic tests performed between 2008 and 2017 confirmed a diagnosis of polyneuropathy. Through analysis of medical records, polyneuropathies were classified according to etiology and neurophysiological aspect. RESULTS: Of the 380 included patients, 59.5% were male, with a median age of 43 years. The main etiologies were: inflammatory (23.7%), hereditary (18.9%), idiopathic (13.7%), multifactorial (11.1%), and diabetes (10.8%). The main electrophysiological patterns were axonal sensorimotor polyneuropathy (36.1%) and "demyelinating and axonal" sensorimotor polyneuropathy (27.9%). Axonal patterns showed greater etiological heterogeneity, with a predominance of idiopathic and multifactorial polyneuropathy, while demyelinating and "demyelinating and axonal" polyneuropathies had a significantly fewer etiologies, with a predominance of hereditary and inflammatory polyneuropathies. CONCLUSION: The main causes of polyneuropathy confirmed by EDX test in this study were those that presented a severe, atypical and/or rapidly progressing pattern. Other causes were hereditary and those that defy clinical reasoning, such as multiple risk factors; some polyneuropathies did not have a specific etiology. EDX tests are useful for etiological diagnosis of rare polyneuropathies, because neurophysiological patterns are correlated with specific etiologies.

Somatosensory evoked potentials in clinical practice: a review.

The authors present a review of the current use of somatosensory evoked potentials (SSEPs) in neurological practice as a non-invasive neurophysiological technique. For this purpose we have reviewed articles published in English or Portuguese in the PubMed and LILACS databases. In this review, we address the role of SSEPs in neurological diseases that affect the central nervous system and the peripheral nervous system, especially in demyelinating diseases, for monitoring coma, trauma and the functioning of sensory pathways during surgical procedures. The latter, along with new areas of research, has become one of the most important applications of SSEPs.

Horner syndrome: tribute to Professor Horner on his 190th birthday.

This paper reviews some aspects of the life and work of Professor Johann Friedrich Horner, on the occasion of the 190th anniversary of his birthday and 152 years after the publication of "Über eine Form von Ptosis". It also shows the importance of the historical description of ptosis, myosis and anhidrosis associating those symptoms with sympathetic cervical damage. He pharmacologically confirmed the impairment of sympathetic innervation to the eye and preserved parasympathetic function.

Myasthenia gravis during pregnancy: what care should be taken?

Myasthenia gravis (MG) is an autoimmune disease in which the peak incidence is among women of childbearing age. For this reason, there is an overlap between the occurrence of this disease and pregnancy. It is known that MG symptoms can worsen during pregnancy and postpartum, and that pregnancy has special characteristics in MG patients. Children born to myasthenic mothers are at risk of having transient neonatal myasthenia. We briefly review the main relationships between MG and pregnancy, and we make recommendations for MG therapy, pregnancy, delivery, breastfeeding and newborns.

Denny-Brown and Pennybacker: 80 years after their pioneering article on electromyography, fibrillation and fasciculation.

We present a historical review, highlighting the role of Professor Derek Denny-Brown and doctor Joseph Buford Pennybacker in the development of current electromyography (EMG), of the 80 years since the publication of his original report in 1938 on fasciculation and fibrillation potentials and the subsequent studies describing most of the electrical changes necessary to perform and interpret the EMG.

Somatosensory evoked potentials in Hirayama disease: A Brazilian study.

BACKGROUND: Hirayama's disease (HD) is characterized by an insidious onset asymmetric weakness and atrophy of the forearm and hand. Taking as a premise, the etiopathogenesis of the disease is attributed to forward displacement of posterior wall of lower cervical dural canal in neck flexion causing marked compression and flattening of lower spinal cord. This may result in compression of the posterior column of the spinal cord and seems likely to result in somatosensory evoked potentials (SSEPs) abnormalities. In the present study, we studied the possible involvement of the lemniscal dorsal pathway in patients with HD. METHODS: SSEPs in upper and lower extremities were prospectively performed in eight patients with HD. All the patients were recruited from the outpatient clinic of a neuromuscular disorder center from South Brazil. SSEPs were obtained by transcutaneous electrical stimulation of the median and posterior tibial nerves, on both sides. We collected the amplitude and the latency of the different components obtained in each channel. The interpretation was based on Brazilian study standards. RESULTS: We evaluated seven men and one woman (mean age 27). The data obtained were compared to a control group consisting of eight patients with spondylotic cervical myelopathy, 6 men and 2 women with mean age of 59 years. The measurements of obtained by the SSEP were also compared between the groups and no significant difference was found for any of them. CONCLUSION: SSEP did not turn out to be an electrophysiological marker in our HD patients.

Celebrating the 70 years of pyridostigmine on therapy of Myasthenia Gravis: historical aspects of the preliminary trials.

Currently, pyridostigmine bromide is an indispensable anticholinesterase agent used worldwide to treat patients with Myasthenia Gravis (MG). However, pyridostigmine bromide was unsuccessful in its "pioneering trials" to treat a series of MG patients. There are important historical landmarks before pyridostigmine bromide becomes useful, safe and indispensable for MG therapy. After 70 years of these "pioneering trials", this article reviews some historical aspects related to them, as well as other preliminary trials using pyridostigmine bromide as therapy for MG patients.

Single-centre experience on genotypic and phenotypic features of southern Brazilian patients with McArdle disease.

McArdle disease (MD) is a metabolic myopathy caused by deficiency of the myophosphorylase enzyme. The aim of our study was to analyse a series of MD patients in Brazil and the correlation between clinical findings, laboratory data, electromyography, muscle biopsy and genetic features. The PYGM gene was analysed by PCR/RLFP and Sanger sequencing. The sample included 12 patients, aged 18-57 years, from unrelated families. Exercise intolerance was present in all cases. Serum creatine kinase levels at rest were increased in all patients. Forearm ischaemic exercise testing in five patients revealed no increase in venous lactate. Needle electromyography presented 'myopathic pattern' in six patients. Muscle biopsy showed vacuolar myopathy in 10 patients and deficiency of myophosphorylase enzyme in all patients. The genetic analysis showed p.R50X as the most common mutation (allelic frequency: 56.25%), other known mutations (p.Y574X, p.G205S, p.W798R, IVS14 + 1G > A and IVS19-1G > A) and a new mutation (p.Asn168Lysfs*15) were also identified. Several features of the disorder were similar to the vast majority of patients worldwide. The genetic findings of this study revealed a range of mutations that are quite similar to the European cohort. The discovery of one novel mutation increases the genotypic heterogeneity of PYGM gene.

Myasthenia gravis and azathioprine treatment: Adverse events related to thiopurine S-methyl-transferase (TPMT) polymorphisms.

Azathioprine (AZA) is the most common immunosuppressive drug used to treat myasthenia gravis (MG). To analyses the prevalence of thiopurine S-methyl-transferase (TPMT) genotypes and their association with adverse events due to azathioprine therapy in MG patients. Allele-specific polymerase chain reaction (PCR) and PCR with restriction fragment length polymorphism (RFLP) analysis were carried out to determine the prevalence of the most common TPMT genotypes (*2, *3A, *3B and *3C) in 50 MG patients from Southern Brazilian. The frequency of adverse reactions due to azathioprine therapy was analysed and correlated with different genotypes groups. The prevalence of TPMT gene variants was 12%. The allelic frequency of variant TPMT*2 (C238G), TPMT*3A (G460A/A719G), TPMT*3B (G460A), and TPMT*3C (A719G) genotypes was 1, 3, 2 and 1%, respectively. Adverse events occurred in 44%, of MG patients, of which 86% were minor and 14% were major. One patient, who presented a major adverse event (bone marrow suppression), was homozygous for the TPMT*3A genotype. Our study estimated the prevalence of TPMT genotypes for Brazilian MG patients. The profile of TPMT genotypes was different from other Brazilian populations. Hardy-Weinberg equilibrium and allelic frequencies of TPMT*3A and TPMT*3B, respectively, were different than expected, a finding that suggests a possible founder effect. Major adverse events were statistically significant for TPMT genotypes compared to wild-type. Although TPMT genotype has been associated with AZA-related adverse events, since no statistically significant difference among wild-type and other TPMT genotypes for minor adverse events, our study supports the view that TPMT genotype alone is not enough to adequately personalise the AZA therapy in MG patients. In conclusion, these results were important to characterise the prevalence of TPMT gene variants in MG patients treated with AZA and correlate the adverse events of this therapy in a real-world outpatient clinic from Southern Brazil.

Characterization of the amyotrophic lateral sclerosis-linked P56S mutation of the VAPB gene in Southern Brazil.

Objective: Amyotrophic lateral sclerosis (ALS) is a rare worldwide heterogeneous neurodegenerative disease with sporadic and familial (FALS) forms. A rare autosomal dominant subtype of FALS was identified in a Brazilian family, classified as ALS type 8 (ALS8) linked to the VAPB gene. The aim of our study was to analyze a series of ALS8 patients from unrelated families in order to further characterize the disease. Methods: We reviewed only patients with probable or definite ALS according to the Awaji criteria being managed at a single center between 2004 and 2018 and with DNA samples available for genetic analysis. A retrospective analysis of clinical, laboratory, and electrophysiological features was performed, relevant data were recorded and DNA was analyzed to detect VAPB gene mutation. Results: Thirty-one ALS patients were eligible for genetic screening for ALS8 and the mutation was detected in five patients from unrelated families. The mean age of onset was 45 ± 5.3 years for the ALS8 group and 47.6 ± 13.1 years for the non-ALS8 group and the time between symptom onset and last follow-up was longer for ALS8 patients. Three patients in the ALS8 group had tremor (60%), four had pain in affected limb (80%) and all had cramps and abdominal protrusion. Conclusions: This study presents the largest series of ALS8 patients in southern Brazil. Our findings demonstrate several clinical features that may be characteristic of ALS8 and confirm that clinicians should suspect ALS8 when the clinical manifestations include cramps, abdominal protrusion, pain, and tremor.