Genetic epidemiology of familial ALS in Brazil.

Many genes associated with familial forms of the amyotrophic lateral sclerosis (fALS) have been identified in European and North American cohorts. However, little is known about the genetic bases of fALS in Latin America and Brazil, in particular. To address this question, we recruited 107 patients with fALS from 93 unrelated families from Southeastern, Southern, and Northeastern regions of the country. A 3-step diagnostic approach was used: 1) Triplet repeat primed polymerase chain reaction to search for C9orf72 expansions, then 2) fragment digestion to search for the c.166 C>T VAPB variant, and finally, 3) whole exome sequencing for those who tested negative. We identified the genetic cause for fALS in 70% of the families. VAPB and C9orf72 were the most frequent genes (30% and 22%, respectively), followed by SOD1, TARDBP, ANXA11, and FUS. Five novel variants in known ALS genes were found, including the SOD1 Val120Leu and ANXA11 Asp40Tyr, which were seen in 2 unrelated families each. In conclusion, VAPB and then C9orf72 are the genes most commonly related to fALS in Brazil.

Laryngeal electromyography in amyotrophic lateral sclerosis.

BACKGROUND: Bulbar involvement is a hallmark of amyotrophic lateral sclerosis (ALS), but surprisingly very few studies have addressed the frequency, pattern and clinical relevance of laryngeal involvement in the disease. METHODS: Twenty-six patients with spinal-onset ALS underwent nasofibroscopy (NF), followed by laryngeal electromyography (LEMG). We also studied resting activity and motor unit potentials of the genioglossus and masseter muscles. RESULTS: Twenty-four patients presented neurogenic changes in at least one laryngeal muscle. There were fibrillation and/or fasciculation potentials associated with chronic neurogenic changes in the same muscle in 16 patients; of these, 9 had no alteration in the genioglossus. We found no patient with tongue neurogenic changes and normal LEMG. NF was abnormal in 14 patients; in the remaining 12, LEMG identified neurogenic changes in 11 of them. CONCLUSION: LEMG is able to identify laryngeal denervation in patients with ALS, sometimes before clinical manifestations are noticed. This technique may be a useful diagnostic tool for selected patients with suspicion of ALS.

CAG repeats ≥ 34 in Ataxin-1 gene are associated with amyotrophic lateral sclerosis in a Brazilian cohort.

Little is known about the genetic basis of amyotrophic lateral sclerosis (ALS) outside Europe and US. In this study, we investigated whether intermediate CAG expansions at ATXN1 were associated to ALS in the Brazilian population. To accomplish that, representative samples from 411 unrelated patients and 436 neurologically normal controls from 6 centers spread over the territory were genotyped to quantify ATXN1 expansions. We found that ATXN1 intermediate-length expansion (≥34 CAG repeats) are associated with the disease (odds ratio = 2.19, 95% CI = 1.081-4.441, p = .026). Most ATXN1-positive patients had classical phenotype, but some of them presented predominant lower motor neuron involvement. None of them had associated ataxia. Frontotemporal dementia was concomitantly found in 12.5% of patients carrying the intermediate ATXN1 expansion. Further studies are needed to validate these findings and to understand the pathophysiological mechanisms that connect ataxin-1 and ALS.

Misdiagnosis and diagnostic delay in non-paraneoplastic sensory neuronopathies.

METHODS: Sensory neuronopathies (SN) are a group of peripheral nerve disorders characterized by multifocal non-length-dependent sensory deficits and sensory ataxia. Its recognition is essential not only for proper management but also to guide the etiological investigation. The uncommon SN clinical picture and its rarity set the conditions for the misdiagnosis and the diagnostic delay, especially in non-paraneoplastic SN. Therefore, our objectives were to characterize the diagnostic odyssey for non-paraneoplastic SN patients, as well as to identify possible associated factors. We consecutively enrolled 48 non-paraneoplastic SN patients followed in a tertiary neuromuscular clinic at the University of Campinas (Brazil). All patients were instructed to retrieve their previous medical records, and we collected the data regarding demographics, disease onset, previous incorrect diagnoses made and the recommended treatments. RESULTS: There were 34 women, with a mean age at the diagnosis of 45.9 ± 12.2 years, and 28/48 (58%) of the patients were idiopathic. Negative sensory symptoms were the heralding symptoms in 25/48 (52%); these were asymmetric in 36/48 (75%) and followed a chronic course in 35/48 (73%). On average, it took 5.4 ± 5.3 years for SN to be diagnosed; patients had an average of 3.4 ± 1.5 incorrect diagnoses. A disease onset before the age of 40 was associated to shorter diagnosis delay (3.7 ± 3.4 vs. 7.8 ± 6.7 years, p = 0.01). CONCLUSIONS: These results suggest that diagnostic delay and misdiagnosis are frequent in non-paraneoplastic SN patients. As in other rare conditions, increased awareness in all the healthcare system levels is paramount to ensure accurate diagnosis and to improve care of these patients.

Misdiagnosis and diagnostic delay in non-paraneoplastic sensory neuronopathies / Erro e atraso diagnóstico nas neuronopatias sensitivas não paraneoplásicas

ABSTRACT Sensory neuronopathies (SN) are a group of peripheral nerve disorders characterized by multifocal non-length-dependent sensory deficits and sensory ataxia. Its recognition is essential not only for proper management but also to guide the etiological investigation. The uncommon SN clinical picture and its rarity set the conditions for the misdiagnosis and the diagnostic delay, especially in non-paraneoplastic SN. Therefore, our objectives were to characterize the diagnostic odyssey for non-paraneoplastic SN patients, as well as to identify possible associated factors. Methods We consecutively enrolled 48 non-paraneoplastic SN patients followed in a tertiary neuromuscular clinic at the University of Campinas (Brazil). All patients were instructed to retrieve their previous medical records, and we collected the data regarding demographics, disease onset, previous incorrect diagnoses made and the recommended treatments. Results There were 34 women, with a mean age at the diagnosis of 45.9 ± 12.2 years, and 28/48 (58%) of the patients were idiopathic. Negative sensory symptoms were the heralding symptoms in 25/48 (52%); these were asymmetric in 36/48 (75%) and followed a chronic course in 35/48 (73%). On average, it took 5.4 ± 5.3 years for SN to be diagnosed; patients had an average of 3.4 ± 1.5 incorrect diagnoses. A disease onset before the age of 40 was associated to shorter diagnosis delay (3.7 ± 3.4 vs. 7.8 ± 6.7 years, p = 0.01). Conclusions These results suggest that diagnostic delay and misdiagnosis are frequent in non-paraneoplastic SN patients. As in other rare conditions, increased awareness in all the healthcare system levels is paramount to ensure accurate diagnosis and to improve care of these patients.

RESUMO As neuronopatias sensitivas (NS) representam um grupo de doenças caracterizadas por ataxia sensitiva e déficits sensitivos multifocais e não-comprimento dependentes. O seu reconhecimento é fundamental para o tratamento apropriado e para a investigação de doenças associadas. O quadro clínico pouco frequente aliado à baixa prevalência, especialmente das formas não-paraneoplásicas (NSnp), colaboram para o atraso e erro no diagnóstico. Os objetivos desse trabalho são descrever a odisseia diagnóstica dos pacientes com NSnp e tentar identificar possíveis fatores associados. Métodos Foram incluídos consecutivamente 48 pacientes com NSnp acompanhados no ambulatório de doenças neuromusculares da Universidade Estadual de Campinas (Brasil). Dados demográficos e sobre o início da NS (incluindo diagnósticos que lhes foram dados e tratamentos prescritos) foram coletados. Resultados Na coorte descrita havia 34 mulheres e a idade ao diagnóstico era de 45,9 ± 12,2 anos. Os sintomas inaugurais eram sensitivos deficitários em 25/48 (52%) dos pacientes, sendo assimétricos em 36/48 (75%) e de evolução crônica em 35/48 (73%). Para 28/48 (58%) dos pacientes a NS era idiopática. Em média, os pacientes com NSnp tiveram um atraso diagnóstico de 5,4 ± 5,3 anos com uma média de 3,4 ± 1,5 diagnósticos incorretos. Pacientes com início antes dos 40 anos tiveram diagnóstico mais precoce que aqueles com início tardio (3,7 ± 3,4 vs. 7,8 ± 6,7 anos, p = 0,01). Conclusão Os dados ora apresentados sugerem que o erro e o atraso diagnóstico são frequentes e impactam os pacientes com NS. A importância do diagnóstico das NS deve ser constante em todos os níveis do sistema de saúde para o diagnóstico correto e a consequente melhora no cuidado a esses pacientes.

Autonomic dysfunction is frequent and disabling in non-paraneoplastic sensory neuronopathies.

INTRODUCTION: Sensory neuronopathies (SN) are characterized by asymmetric non-length dependent sensory deficits and sensory ataxia. Autonomic dysfunction in SN was not yet evaluated regarding its frequency, characteristics and relationship to sensory deficits. To address these issues, we performed a comprehensive clinical and neurophysiological evaluation of a large cohort of patients with non-paraneoplastic SN (np-SN). METHODS: We enrolled 50 consecutive patients with npSN and 32 age/sex-matched healthy controls. They were clinically evaluated (SCOPA-Aut scale) and underwent neurophysiological autonomic assessment (quantitative sudomotor axon reflex test, heart rate variability and sympathetic skin response). RESULTS: Mean age of patients was 50.9 ±â€¯10.3 years and there were 18 men. npSN patients had higher SCOPA-Aut scores than controls (26.63 ±â€¯12.72 vs. 12.66 ±â€¯9.11, p < .001). QSART was abnormal in 92% of the patients - sweat volumes in all examined sites were smaller among patients (p < .001). Cardiovascular autonomic neuropathy was more frequent in these patients as well (p < .001). CONCLUSION: Altogether our results suggest that autonomic dysfunction in distinct domains is frequent in npSN patients. These findings suggest that the clinical picture of npSN is related to a double neuronopathy: sensory and autonomic.

SPG11 mutations cause widespread white matter and basal ganglia abnormalities, but restricted cortical damage.

SPG11 mutations are the major cause of autosomal recessive Hereditary Spastic Paraplegia. The disease has a wide phenotypic variability indicating many regions of the nervous system besides the corticospinal tract are affected. Despite this, anatomical and phenotypic characterization is restricted. In the present study, we investigate the anatomical abnormalities related to SPG11 mutations and how they relate to clinical and cognitive measures. Moreover, we aim to depict how the disease course influences the regions affected, unraveling different susceptibility of specific neuronal populations. We performed clinical and paraclinical studies encompassing neuropsychological, neuroimaging, and neurophysiological tools in a cohort of twenty-five patients and age matched controls. We assessed cortical thickness (FreeSurfer software), deep grey matter volumes (T1-MultiAtlas tool), white matter microstructural damage (DTI-MultiAtlas) and spinal cord morphometry (Spineseg software) on a 3 T MRI scan. Mean age and disease duration were 29 and 13.2 years respectively. Sixty-four percent of the patients were wheelchair bound while 84% were demented. We were able to unfold a diffuse pattern of white matter integrity loss as well as basal ganglia and spinal cord atrophy. Such findings contrasted with a restricted pattern of cortical thinning (motor, limbic and parietal cortices). Electromyography revealed motor neuronopathy affecting 96% of the probands. Correlations with disease duration pointed towards a progressive degeneration of multiple grey matter structures and spinal cord, but not of the white matter. SPG11-related hereditary spastic paraplegia is characterized by selective neuronal vulnerability, in which a precocious and widespread white matter involvement is later followed by a restricted but clearly progressive grey matter degeneration.