Navegando por Autor "Andrade, Helen Maia Tavares de"
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Artigo CAG repeats ≥ 34 in Ataxin-1 gene are associated with amyotrophic lateral sclerosis in a Brazilian cohort(Elsevier, 2020) Dourado Junior, Mário Emílio Teixeira; Gonçalves, João Pedro Nunes; Andrade, Helen Maia Tavares de; Cintra, Vívian Pedigone; et, al; https://orcid.org/0000-0002-9462-2294Little 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.Artigo Intermediate-length CAG repeat in ATXN2 is associated with increased risk for amyotrophic lateral sclerosis in Brazilian patients(Elsevier, 2018) Dourado Junior, Mário Emílio Teixeira; Andrade, Helen Maia Tavares de; Cintra, Vívian Pedigone; et al.; https://orcid.org/0000-0002-9462-2294Intermediate-length cytosine-adenine-guanine nucleotide repeat expansions in the ATXN2 gene (which encodes for the protein Ataxin-2) have been linked to increased risk for amyotrophic lateral sclerosis (ALS) in different populations. There is no such study in the Brazilian population, which has a mixed ethnic background. We have thus selected 459 patients with ALS (372 Sporadic ALS and 87 Familial ALS) and 468 control subjects from 6 Brazilian centers to investigate this point. We performed polymerase chain reaction to determine the length of the ATXN2 alleles. Polymerase chain reaction products were resolved using capillary electrophoresis on ABI 3500 × l capillary sequencer. We found that ATXN2 intermediate-length expansions (larger than 26 repeats) were associated with an increased risk for ALS (odds ratio = 2.56, 95% confidence interval: 1.29–5.08, p = 0.005). Phenotype in patients with and without ATXN2 expansions was similar. Our findings support the hypothesis that ATXN2 plays an important role in the pathogenesis of ALS also in the Brazilian population.