Visual Evoked Potentials in Neuromyelitis Optica Spectrum Disorders.

BACKGROUND: Neuromyelitis optica spectrum disorders (NMOSDs) are rare antibody-mediated disorders of the central nervous system, with a predilection for the spinal cord and optic nerves. The clinical utility of evoked potential recordings (EPs) has already been established for multiple sclerosis, in particular, that of the abnormal visual evoked potentials (VEP), a key criterion in the McDonald diagnostic criteria for MS. However, there have been few reports on EPs in patients with NMOSD. AIM: The aim of our study was to assess the possible involvement of the optical pathway through VEP responses in patients with NMOSD. METHODS: VEPs were prospectively performed in 13 patients with NMOSD. All the patients were recruited from the outpatient clinic of a demyelinating diseases center. The recording was done as recommended by the International Federation of Clinical Neurophysiology. RESULTS: We evaluated the eyes of 12 women with a mean age of 42 years and of one man who was 25 years old. In 6 of the examined eye samples, a response was not obtained, while in the remaining 20 eye samples, we found a significant increase in P100 latency without amplitude change. CONCLUSION: VEPs showed a significant increase in P100 latency. VEP assessment is a non-invasive, painless, fast, and low-cost exam that provides neurophysiological data for diagnosis of NMOSD.

Clinical follow-up of pregnancy in myasthenia gravis patients.

This study aimed to analyze the outcome and impact of pregnancy in women with myasthenia gravis (MG). Obstetric and clinical data were retrospectively analyzed before, during and after pregnancy. Predictors of outcome were studied. We included 35 pregnancies from 21 MG patients. In the course of MG symptoms in 30 pregnancies with live births, 50% deteriorated (mainly during the second trimester, p = 0.028), 30% improved, and 20% remained unchanged. The deterioration group had more frequent abnormal repetitive nerve stimulation (RNS) (p = 0.028) and lower myasthenia gravis composite (MGC) scores (p = 0.045) before pregnancy. The improvement group was associated with higher MGC scores (p = 0.012) before pregnancy. The no-change group was associated with longer duration of MG (p = 0.026) and normal RNS (p = 0.008) before pregnancy. The course of MG in the second pregnancy was different from that in the previous pregnancy in 65.3% of cases. Obstetric complications were reported in 20 pregnancies; the most common was preterm premature rupture of membranes (PPROM) (25.8%), and the most severe were abortion (11.4%) and fetal death (2.9%). Most of the patients delivered via caesarean section (66.7%). Spinal anesthesia was performed in 73.3%. Transient neonatal myasthenia gravis occurred in 12.9% of live-born infants, and no predictors were found. In conclusion, severity and duration of MG, RNS and treatment influence MG and pregnancy. Pregnant MG patients have greater rates of PPROM and caesarean delivery. Our data suggest that duration of MG, MGC and RNS before pregnancy may be useful in helping to predict the course of MG during pregnancy.

Novel synaptobrevin-1 mutation causes fatal congenital myasthenic syndrome.

OBJECTIVE: To identify the molecular basis and elucidate the pathogenesis of a fatal congenital myasthenic syndrome. METHODS: We performed clinical electrophysiology studies, exome and Sanger sequencing, and analyzed functional consequences of the identified mutation. RESULTS: Clinical electrophysiology studies of the patient revealed several-fold potentiation of the evoked muscle action potential by high frequency nerve stimulation pointing to a presynaptic defect. Exome sequencing identified a homozygous c.340delA frameshift mutation in synaptobrevin 1 (SYB1), one of the three SNARE proteins essential for synaptic vesicle exocytosis. Analysis of both human spinal cord gray matter and normal human muscle revealed expression of the SYB1A and SYB1D isoforms, predicting expression of one or both isoforms in the motor nerve terminal. The identified mutation elongates the intravesicular C-terminus of the A isoform from 5 to 71, and of the D isoform from 4 to 31 residues. Transfection of either mutant isoform into bovine chromaffin cells markedly reduces depolarization-evoked exocytosis, and transfection of either mutant isoform into HEK cells significantly decreases expression of either mutant compared to wild type. INTERPRETATION: The mutation is pathogenic because elongation of the intravesicular C-terminus of the A and D isoforms increases the energy required to move their C-terminus into the synaptic vesicle membrane, a key step for fusion of the synaptic vesicle with the presynaptic membrane, and because it is predicted to reduce expression of either isoform in the nerve terminal.

Niemann-Pick disease type C: a case series of Brazilian patients.

UNLABELLED: The aim of the study was to analyze a series of Brazilian patients with Niemann-Pick disease type C (NP-C). METHOD: Correlations between clinical findings, laboratory data, molecular findings and treatment response are presented. RESULT: The sample consisted of 5 patients aged 8 to 26 years. Vertical supranuclear gaze palsy, cerebellar ataxia, dementia, dystonia and dysarthria were present in all cases. Filipin staining showed the "classical" pattern in two patients and a "variant" pattern in three patients. Molecular analysis found mutations in the NPC1 gene in all alleles. Miglustat treatment was administered to 4 patients. CONCLUSION: Although filipin staining should be used to confirm the diagnosis, bone marrow sea-blue histiocytes often help to diagnosis of NP-C. The p.P1007A mutation seems to be correlated with the "variant" pattern in filipin staining. Miglustat treatment response seems to be correlated with the age at disease onset and disability scale score at diagnosis.

Niemann-Pick disease type C: a case series of Brazilian patients / Doenca de Niemann-Pick tipo C: serie de casos de pacientes brasileiros

The aim of the study was to analyze a series of Brazilian patients with Niemann-Pick disease type C (NP-C). Method Correlations between clinical findings, laboratory data, molecular findings and treatment response are presented. Result The sample consisted of 5 patients aged 8 to 26 years. Vertical supranuclear gaze palsy, cerebellar ataxia, dementia, dystonia and dysarthria were present in all cases. Filipin staining showed the “classical” pattern in two patients and a “variant” pattern in three patients. Molecular analysis found mutations in the NPC1 gene in all alleles. Miglustat treatment was administered to 4 patients. Conclusion Although filipin staining should be used to confirm the diagnosis, bone marrow sea-blue histiocytes often help to diagnosis of NP-C. The p.P1007A mutation seems to be correlated with the “variant” pattern in filipin staining. Miglustat treatment response seems to be correlated with the age at disease onset and disability scale score at diagnosis. .

O objetivo desse estudo foi analisar uma série de casos de pacientes brasileiros com doença de Niemann-Pick tipo C (NP-C). Método Correlação entre manifestações clínicas, alterações laboratoriais, estudo molecular e resposta ao tratamento foram realizadas. Resultado A amostra consiste de 5 pacientes com idade entre 8 e 26 anos. Paralisia do olhar vertical supranuclear, ataxia cerebelar, demência, distonia e disartria estavam presentes em todos os casos. Coloração de filipina na cultura de fibroblastos mostrou padrão “clássico” em dois pacientes e padrão “variante” em três casos. O estudo molecular encontrou mutações no gene NPC1 em todos os alelos. O tratamento com miglustate foi realizado em 4 pacientes. Conclusão Embora coloração de filipina seja utilizada para confirmar o diagnóstico, o histiócito azul-marinho no aspirado de medula óssea frequentemente auxilia a confirmar o diagnóstico de NP-C. A mutação p.P1007A está correlacionada com o padrão “ variante” na coloração de filipina. A resposta ao tratamento com miglustate parece estar correlacionada com a idade e escore de desabilidade no momento do diagnóstico. .

Salbutamol therapy in congenital myasthenic syndrome due to DOK7 mutation.

INTRODUCTION: Salbutamol is a selective B2-adrenergic agonist, which has previously been described to be associated with partial improvement of myasthenia gravis and congenital myasthenic syndromes (CMS). In this study, we analyzed the effect of salbutamol in five patients with Dok-7 CMS. METHODS: We studied 5 patients (2 male and 3 female), with a mean age of 27±11.06 years, who harbored c.1124_1127dupTGCC, p.G64R and/or p.S45L mutations in DOK7 gene. Salbutamol was given at a dose of 2mg three times daily (6 mg/day) to all patients. The response was assessed by QMG score at baseline, 3, 6, 9 and 12 months; ADL-MG score and 6 minute walk test at baseline and after 12 months during follow-up clinic visits. Side effect profile of salbutamol was also evaluated. RESULTS: We noted an increasingly positive response as measured by the QMG score after 3 months of salbutamol treatment. Improvement in specific subcomponents of the QMG score such as leg outstretched in 45° supine was most marked. In ADL-MG scores and 6 minute walk test, comparison between baseline and after 12 months revealed a clear beneficial response. Salbutamol was well tolerated in all patients. CONCLUSIONS: Salbutamol is an effective treatment in Dok-7 CMS. This study provides class IV evidence that salbutamol given at a dose 6 mg/day improves function as measured by the QMG score, ADL-MG score and 6 minute walk test.

Electrophysiological characteristics in four patients from Brazil with stiff person syndrome.

Stiff person syndrome (SPS) is a rare immune-mediated disorder of the central nervous system characterized by muscle rigidity and episodic muscle spasms. The diagnosis of SPS is based on electrophysiological studies. We analyzed the electrophysiological features in four patients from Brazil who fulfilled the clinical criteria for SPS. The most common electrophysiological abnormalities were continuous motor unit activity, co-contracting, and the presence of the cutaneomuscular reflex. Despite all patients having clinical characteristics of SPS during the disease, no patient met all the electrophysiological criteria for SPS even after repeat electrophysiological studies. This shows that a diagnosis of SPS should not be restricted to patients with all the classic electrophysiological changes but should be considered in the presence of one or some of those changes.