First case of SARS-COV-2 sequencing in cerebrospinal fluid of a patient with suspected demyelinating disease.

The association between coronaviruses and central nervous system (CNS) demyelinating lesions has been previously shown. However, no case has been described of an association between the novel coronavirus (SARS-COV-2) and CNS demyelinating disease so far. SARS-COV-2 was previously detected in cerebrospinal fluid (CSF) sample of a patient with encephalitis. However, the virus identity was not confirmed by deep sequencing of SARS-COV-2 detected in the CSF. Here, we report a case of a patient with mild respiratory symptoms and neurological manifestations compatible with clinically isolated syndrome. The viral genome of SARS-COV-2 was detected and sequenced in CSF with 99.74-100% similarity between the patient virus and worldwide sequences. This report suggests a possible association of SARS-COV-2 infection with neurological symptoms of demyelinating disease, even in the absence of relevant upper respiratory tract infection signs.

Minimal prevalence of Huntington's disease in the South of Brazil and instability of the expanded CAG tract during intergenerational transmissions.

Huntington's disease (HD) is due to dominant expansions of the CAG repeat of the HTT gene. Meiotic instability of the (CAG)n might impact the disorder frequency. We report on HD minimal prevalence in Rio Grande do Sul (RS) state, Brazil, and on intergenerational instability of the (CAG)n in HD families. Symptomatic and at-risk subjects from 179 HD families were ascertained between 2013 and 2016. Clinical, molecular and family history data were obtained. Expanded (CAG)n length differences between parent and child (delta-expanded-(CAG)n) were calculated. Effect of parental age on the (CAG)n instability upon transmission was inferred by correlating delta-expanded-(CAG)n between siblings to their age differences. HD minimal prevalence in RS state was estimated as 1.85:100,000 inhabitants. Alleles with (CAG)27-35 were found on 21/384 non-disease associated chromosomes (5.5%); among 253 expanded alleles, four (1.6%) were within reduced penetrance range with (CAG)36-39. In 32 direct transmissions, mean instability was larger among paternal than maternal transmissions. In direct transmissions and in 51 sibling pairs, parental age at the time of child birth were not correlated with delta-expanded-(CAG)n. Briefly, HD prevalence in RS state was lower than those reported for European populations. Expanded (CAG)n transmissions were unstable and not associated to parental age.

Spinocerebellar ataxias in Brazil--frequencies and modulating effects of related genes.

This study describes the frequency of spinocerebellar ataxias and of CAG repeats range in different geographical regions of Brazil, and explores the hypothetical role of normal CAG repeats at ATXN1, ATXN2, ATXN3, CACNA1A, and ATXN7 genes on age at onset and on neurological findings. Patients with symptoms and family history compatible with a SCA were recruited in 11 cities of the country; clinical data and DNA samples were collected. Capillary electrophoresis was performed to detect CAG lengths at SCA1, SCA2, SCA3/MJD, SCA6, SCA7, SCA12, SCA17, and DRPLA associated genes, and a repeat primed PCR was used to detect ATTCT expansions at SCA10 gene. Five hundred forty-four patients (359 families) were included. There were 214 SCA3/MJD families (59.6 %), 28 SCA2 (7.8 %), 20 SCA7 (5.6 %), 15 SCA1 (4.2 %), 12 SCA10 (3.3 %), 5 SCA6 (1.4 %), and 65 families without a molecular diagnosis (18.1 %). Divergent rates of SCA3/MJD, SCA2, and SCA7 were seen in regions with different ethnic backgrounds. 64.7 % of our SCA10 patients presented seizures. Among SCA2 patients, longer ATXN3 CAG alleles were associated with earlier ages at onset (p < 0.036, linear regression). A portrait of SCAs in Brazil was obtained, where variation in frequencies seemed to parallel ethnic differences. New potential interactions between some SCA-related genes were presented.