Spinocerebellar ataxia type 2 has multiple ancestral origins

INTRODUCTION

Spinocerebellar ataxia type 2 (SCA2) is a dominant neurodegenerative disorder due to expansions of a CAG repeat tract (CAGexp) at the ATXN2 gene. Previous studies found only one ancestral haplotype worldwide, with a C allele at rs695871. This homogeneity was unexpected, given the severe anticipations related to SCA2. We aimed to describe informative ancestral haplotypes found in South American SCA2 families.

METHODS

Seventy-seven SCA2 index cases were recruited from Brazil, Peru, and Uruguay; 263 normal chromosomes were used as controls. The SNPs rs9300319, rs3809274, rs695871, rs1236900 and rs593226, and the STRs D12S1329, D12S1333, D12S1672 and D12S1332, were used to reconstruct haplotypes.

RESULTS

Eleven ancestral haplotypes were found in SCA2 families. The most frequent ones were A-G-C-C-C (46.7 % of families), G-C-C-C-C (24.6 %) and A-C-C-C-C (10.3 %) and their mean (sd) CAGexp were 41.68 (3.55), 40.42 (4.11) and 45.67 (9.70) (p = 0.055), respectively. In contrast, the mean (sd) CAG lengths at normal alleles grouped per haplotypes G-C-G-A-T, A-G-C-C-C and G-C-C-C-C were 22.97 (3.93), 23.85 (3.59), and 30.81 (4.27) (p < 0.001), respectively. The other SCA2 haplotypes were rare: among them, a G-C-G-A-T lineage was found, evidencing a G allele in rs695871.

CONCLUSION

We identified several distinct ancestral haplotypes in SCA2 families, including an unexpected lineage with a G allele at rs695871, a variation never found in hundreds of SCA2 patients studied worldwide. SCA2 has multiple origins in South America, and more studies should be done in other regions of the world.

An Exploratory Survey on the Care for Ataxic Patients in the American Continents and the Caribbean

Little is known about access of rare disease carriers to health care. To increase this knowledge, the Pan American Hereditary Ataxia Network (PAHAN) conducted an exploratory survey about care for hereditary ataxias in American continents and the Caribbean. A questionnaire was sent to health professionals about the hereditary ataxias identified; access to care; and local teaching and research. The number of ataxics under current care per 100,000 inhabitants was subtracted from the expected overall prevalence of 6/100,000, to estimate the prevalence of uncovered ataxic patients. Local Human Development Indexes (HDI) were used to measure socio-economic factors. Twenty-six sites participated. Twelve sites had very high, 13 had high, and one site had medium HDI. Participants reported on 2239 and 602 patients with spinocerebellar ataxias and recessive forms under current care. The number of patients under current care per inhabitants varied between 0.14 and 12/100,000. The estimated prevalence of uncovered ataxic patients was inversely proportional to HDIs (rho = 0.665, p = 0.003). Access to diagnosis, pre-symptomatic tests, and rehabilitation were associated with HDIs. More and better molecular diagnostic tools, protocols and guidelines, and professional training for ataxia care were the top priorities common to all respondents. Evidence of inequalities was confirmed. Lower HDIs were associated with high potential numbers of uncovered ataxic subjects, and with lack of molecular diagnosis, pre-symptomatic testing, and rehabilitation. More and better diagnostic tools, guidelines, and professional training were priorities to all sites. PAHAN consortium might help with the last two tasks.

National stroke management plan in Uruguay: Challenges and opportunities

Stroke accounts for 5.5% of the national Global Burden of Disease (GBD) and ~2,000 deaths per year in Uruguay. To respond to this medical emergency, the Ministry of Public Health (MPH) of Uruguay devised the National Stroke Plan (NSP). Scientific associations, universities, scholars, and patient organizations, both at the national and international levels, took part in the process, which ended with the generation of the national stroke management guidelines, including measures based on the best evidence available. This was accompanied by presidential regulatory decrees and several ordinances that set the foundations of the legal framework for their implementation as of 2020. Forty-two Stroke Ready Centers (SRC) and seven Comprehensive Stroke Centers (CSC) were strategically established and interlinked to ensure compliance with international accessibility recommendations, offering, in turn, the required training for their healthcare teams. A pre-hospital care protocol was also created for all countrywide mobile units. For NSP assessment, stroke was included as a "Care Goal (objective)" for the whole health system, providing the involved healthcare organizations with a financial incentive for compliance with the basic objectives related to the treatment of hyper acute stroke. The NSP came into force during the COVID-19 pandemic and, considering the special circumstances imposed, it made it possible to maintain hyper acute medical care and increase population access to recanalization treatment, particularly mechanical thrombectomy. The purpose of this article is to share our experience in the development of the NSP by describing some preliminary outcomes.

Fighting Against Stroke in Latin America: A Joint Effort of Medical Professional Societies and Governments

Introduction: Stroke is one of the leading causes of death in Latin America, a region with countless gaps to be addressed to decrease its burden. In 2018, at the first Latin American Stroke Ministerial Meeting, stroke physician and healthcare manager representatives from 13 countries signed the Declaration of Gramado with the priorities to improve the region, with the commitment to implement all evidence-based strategies for stroke care. The second meeting in March 2020 reviewed the achievements in 2 years and discussed new objectives. This paper will review the 2-year advances and future plans of the Latin American alliance for stroke. Method: In March 2020, a survey based on the Declaration of Gramado items was sent to the neurologists participants of the Stroke Ministerial Meetings. The results were confirmed with representatives of the Ministries of Health and leaders from the countries at the second Latin American Stroke Ministerial Meeting. Results: In 2 years, public stroke awareness initiatives increased from 25 to 75% of countries. All countries have started programs to encourage physical activity, and there has been an increase in the number of countries that implement, at least partially, strategies to identify and treat hypertension, diabetes, and lifestyle risk factors. Programs to identify and treat dyslipidemia and atrial fibrillation still remained poor. The number of stroke centers increased from 322 to 448, all of them providing intravenous thrombolysis, with an increase in countries with stroke units. All countries have mechanical thrombectomy, but mostly restricted to a few private hospitals. Pre-hospital organization remains limited. The utilization of telemedicine has increased but is restricted to a few hospitals and is not widely available throughout the country. Patients have late, if any, access to rehabilitation after hospital discharge. Conclusion: The initiative to collaborate, exchange experiences, and unite societies and governments to improve stroke care in Latin America has yielded good results. Important advances have been made in the region in terms of increasing the number of acute stroke care services, implementing reperfusion treatments and creating programs for the detection and treatment of risk factors. We hope that this approach can reduce inequalities in stroke care in Latin America and serves as a model for other under-resourced environments.

Prodromal symptoms in epileptic patients: clinical characterization of the pre-ictal phase

Although recent advances in seizure anticipation have been achieved with the development of several biomathematical electroencephalographic (EEG) methods, pre-ictal clinical phenomena have not been extensively investigated. The aim of the study was to thoroughly analyze premonitory or prodromal symptoms (PS) in a randomly selected sample of 100 adult epileptic patients. A semi-structured protocol was used for in-person interviews to both patients and observers. PS were found in 39% of patients, the most frequent ones being behavioral, cognitive and mood changes. Both patients with focal and generalized epilepsies reported prodromes, although they were more frequently found in the former group. PS were mostly perceived preceding complex partial and generalized tonic-clonic seizures. Prodromal symptoms were reported to have an insidious onset and their duration ranged from 30min to several hours. The potential value of prodromes in seizure anticipation would allow the use of preventive and therapeutic measures, including drugs, neurostimulation procedures and behavioral intervention.

(GCG)11 founder mutation in the PABPN1 gene of OPMD Uruguayan families

The dominant oculo-pharyngeal muscular dystrophy mutation consists of an expanded (GCN)(12-17) in the coding region of the PolyA Binding Protein Nuclear 1 gene. A founder effect has been demonstrated in Canadian and Bukhara Jewish populations with relatively high prevalence of this disease. Since the oculo-pharyngeal muscular dystrophy prevalence was remarkably high in Southern Uruguay, a founder effect was hypothesized. To identify the ancestral haplotype we determined the (GCN) repeat number and the variants of four intragenic SNPs in Uruguayan OPMD families and a control sample. All families carrying the mutation (GCG)(11)(GCA)(3)(GCG) shared a common ancestral haplotype and the age of the mutation was estimated in 37-53 generations by a composite likelihood method. One family carrying the (GCG)(9)(GCA)(3)(GCG) allele had a different haplotype. The genealogical and molecular data suggested that the common ancestors were Canary Islands' settlers that arrived in Uruguay in the XIX century.