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Background Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects the upper and lower motor neurons. The correct diagnosis at the onset of the disease is sometimes very difficult, due to the symptoms being very similar to those of other neurological syndromes. Objective This study aimed to analyze the initial manifestations, the specialty of the first physician visited due the initial complaint, the misdiagnoses, as well as the unnecessary surgical interventions in a new ALS Brazilian population. Methods The medical records of 173 patients with typical ALS were reviewed. Results The present study demonstrated that other symptoms, besides weakness, were very frequent as initial presentation of ALS, and orthopedics was the medical specialty most sought by patients at the onset of symptoms. Our frequency of misdiagnoses was 69.7%, and in 7.1% of them, an unnecessary surgical intervention was performed. Conclusions Amyotrophic lateral sclerosis presents a very large pool of signs and symptoms; therefore, there is an urgent need of increasing the disease awareness to other specialties due to the high frequency of misdiagnoses observed in clinical practice. Resumo Antecedentes A esclerose lateral amiotrófica (ELA) é uma doença neurodegenerativa que afeta os neurônios motores superior e inferior. O diagnóstico correto no início da doença é, às vezes, muito difícil, pois os sintomas de início são muito semelhantes aos de outras síndromes neurológicas. Objetivo Este estudo teve como objetivo analisar as manifestações iniciais, a especialidade do primeiro médico visitado devido à queixa inicial, os diagnósticos errôneos, bem como as intervenções cirúrgicas desnecessárias em uma nova população brasileira acometida por ELA. Métodos Os prontuários médicos de 173 pacientes com ELA típica foram revisados. Resultados O presente estudo demonstrou que outros sintomas, além da fraqueza, foram muito frequentes como apresentação inicial da ELA, sendo a ortopedia a especialidade médica mais procurada pelos pacientes no início dos sintomas. Nossa frequência de diagnósticos errôneos foi de 69,7%, e em 7,1% deles foi realizada intervenção cirúrgica desnecessária. Conclusões A ELA apresenta um conjunto amplo de sinais e sintomas; portanto, há necessidade urgente de uma melhor educação de outras especialidades devido à alta frequência de diagnósticos equivocados observada na prática clínica.

Significant progress has been made in elucidating single nucleotide polymorphism diversity in the human population. However, the majority of the variation space in the genome is structural and remains partially elusive. One form of structural variation is tandem repeats (TRs). Expansion of TRs are responsible for over 40 diseases, but we hypothesize these represent only a fraction of the pathogenic repeat expansions that exist. Here we characterize long or expanded TR variation in 1,115 human genomes as well as a replication cohort of 2,504 genomes, identified using ExpansionHunter Denovo. We found that individual genomes typically harbor several rare, large TRs, generally in non-coding regions of the genome. We noticed that these large TRs are enriched in their proximity to Alu elements. The vast majority of these large TRs seem to be expansions of smaller TRs that are already present in the reference genome. We are providing this TR profile as a resource for comparison to undiagnosed rare disease genomes in order to detect novel disease-causing repeat expansions.

Peroxiredoxin 3 (PRDX3) belongs to a superfamily of peroxidases that function as protective antioxidant enzymes. Among the six isoforms (PRDX1–PRDX6), PRDX3 is the only protein exclusively localized to the mitochondria, which are the main source of reactive oxygen species. Excessive levels of reactive oxygen species are harmful to cells, inducing mitochondrial dysfunction, DNA damage, lipid and protein oxidation and ultimately apoptosis. Neuronal cell damage induced by oxidative stress has been associated with numerous neurodegenerative disorders including Alzheimer’s and Parkinson’s diseases. Leveraging the large aggregation of genomic ataxia datasets from the PREPARE (Preparing for Therapies in Autosomal Recessive Ataxias) network, we identified recessive mutations in PRDX3 as the genetic cause of cerebellar ataxia in five unrelated families, providing further evidence for oxidative stress in the pathogenesis of neurodegeneration. The clinical presentation of individuals with PRDX3 mutations consists of mild-to-moderate progressive cerebellar ataxia with concomitant hyper- and hypokinetic movement disorders, severe early-onset cerebellar atrophy, and in part olivary and brainstem degeneration. Patient fibroblasts showed a lack of PRDX3 protein, resulting in decreased glutathione peroxidase activity and decreased mitochondrial maximal respiratory capacity. Moreover, PRDX3 knockdown in cerebellar medulloblastoma cells resulted in significantly decreased cell viability, increased H2O2 levels and increased susceptibility to apoptosis triggered by reactive oxygen species. Pan-neuronal and pan-glial in vivo models of Drosophila revealed aberrant locomotor phenotypes and reduced survival times upon exposure to oxidative stress. Our findings reveal a central role for mitochondria and the implication of oxidative stress in PRDX3 disease pathogenesis and cerebellar vulnerability and suggest targets for future therapeutic approaches.