Netherlands ALS Foundation.

SummaryBackgroundAmyotrophic lateral sclerosis shares characteristics with some cancers, such as onset being more common in later life, progression usually being rapid, the disease affecting a particular cell type, and showing complex inheritance. We used a model originally applied to cancer epidemiology to investigate the hypothesis that amyotrophic lateral sclerosis is a multistep process.MethodsWe generated incidence data by age and sex from amyotrophic lateral sclerosis population registers in Ireland (registration dates 1995–2012), the Netherlands (2006–12), Italy (1995–2004), Scotland (1989–98), and England (2002–09), and calculated age and sex-adjusted incidences for each register. We regressed the log of age-specific incidence against the log of age with least squares regression. We did the analyses within each register, and also did a combined analysis, adjusting for register.FindingsWe identified 6274 cases of amyotrophic lateral sclerosis from a catchment population of about 34 million people. We noted a linear relationship between log incidence and log age in all five registers: England r2=0·95, Ireland r2=0·99, Italy r2=0·95, the Netherlands r2=0·99, and Scotland r2=0·97; overall r2=0·99. All five registers gave similar estimates of the linear slope ranging from 4·5 to 5·1, with overlapping confidence intervals. The combination of all five registers gave an overall slope of 4·8 (95% CI 4·5–5·0), with similar estimates for men (4·6, 4·3–4·9) and women (5·0, 4·5–5·5).InterpretationA linear relationship between the log incidence and log age of onset of amyotrophic lateral sclerosis is consistent with a multistage model of disease. The slope estimate suggests that amyotrophic lateral sclerosis is a six-step process. Identification of these steps could lead to preventive and therapeutic avenues.FundingUK Medical Research Council; UK Economic and Social Research Council; Ireland Health Research Board; The Netherlands Organisation for Health Research and Development (ZonMw); the Ministry of Health and Ministry of Education, University, and Research in Italy; the Motor Neurone Disease Association of England, Wales, and Northern Ireland; and the European Commission (Seventh Framework Programme).

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ObjectiveAmyotrophic lateral sclerosis (ALS) incidence rates are consistent with the hypothesis that ALS is a multistep process. We tested the hypothesis that carrying a large effect mutation might account for ≥1 steps through the effect of the mutation, thus leaving fewer remaining steps before ALS begins.MethodsWe generated incidence data from an ALS population register in Italy (2007–2015) for which genetic analysis for C9orf72, SOD1, TARDBP, and FUS genes was performed in 82% of incident cases. As confirmation, we used data from ALS cases diagnosed in the Republic of Ireland (2006–2014). We regressed the log of age-specific incidence against the log of age with least-squares regression for the subpopulation carrying disease-associated variation in each separate gene.ResultsOf the 1,077 genetically tested cases, 74 (6.9%) carried C9orf72 mutations, 20 (1.9%) had SOD1 mutations, 15 (1.4%) had TARDBP mutations, and 3 (0.3%) carried FUS mutations. In the whole population, there was a linear relationship between log incidence and log age (r2 = 0.98) with a slope estimate of 4.65 (4.37–4.95), consistent with a 6-step process. The analysis for C9orf72-mutated patients confirmed a linear relationship (r2 = 0.94) with a slope estimate of 2.22 (1.74–2.29), suggesting a 3-step process. This estimate was confirmed by data from the Irish ALS register. The slope estimate was consistent with a 2-step process for SOD1 and with a 4-step process for TARDBP.ConclusionThe identification of a reduced number of steps in patients with ALS with genetic mutations compared to those without mutations supports the idea of ALS as a multistep process and is an important advance for dissecting the pathogenic process in ALS.

Background Amyotrophic lateral sclerosis (ALS) is a progressive debilitating neurodegenerative disease, with a life expectancy of 3-5 years from first symptom. There is compelling evidence that those who attend a multidisciplinary clinic experience improved survival. The purpose of the study was to explore the survival of patients with ALS ascertained through population-based Registers in the Republic of Ireland (RoI) and Northern Ireland (NI), and to determine whether centralisation of services confers advantage compared with communitybased care supported by a specialist care worker. Methods The island of Ireland is divided into two countries, RoI and NI, each with an independent healthcare system. Both countries have population-based ALS Registers with full ascertainment. Data from all 719 incident ALS cases from Ireland and NI, diagnosed between 1 January 2005 and 31 December 2010, were used in the analysis. Results A survival benefit was identified for patients who attended the multidisciplinary ALS clinic in the RoI. (HR 0.59, 95% CI 0.49 to 0.71, p<0.001). This difference was preserved following multivariate analysis. A trend towards improved survival was noted for patients with ALS from NI when compared with RoI patients who did not attend a multidisciplinary clinic. Conclusions Centralised multidisciplinary care confers a survival advantage for patients with ALS and is superior to devolved community-based care. We propose that multiple decision-making processes within a multidisciplinary setting lead to an enriched set of clinical encounters for the patient and carer that enhances clinical outcome.