Genotypes and phenotypes of motor neuron disease: an update of the genetic landscape in Scotland.

BACKGROUND: Using the Clinical Audit Research and Evaluation of Motor Neuron Disease (CARE-MND) database and the Scottish Regenerative Neurology Tissue Bank, we aimed to outline the genetic epidemiology and phenotypes of an incident cohort of people with MND (pwMND) to gain a realistic impression of the genetic landscape and genotype-phenotype associations. METHODS: Phenotypic markers were identified from the CARE-MND platform. Sequence analysis of 48 genes was undertaken. Variants were classified using a structured evidence-based approach. Samples were also tested for C9orf72 hexanucleotide expansions using repeat-prime PCR methodology. RESULTS: 339 pwMND donated a DNA sample: 44 (13.0%) fulfilled criteria for having a pathogenic variant/repeat expansion, 53.5% of those with a family history of MND and 9.3% of those without. The majority (30 (8.8%)) had a pathogenic C9orf72 repeat expansion, including two with intermediate expansions. Having a C9orf72 expansion was associated with a significantly lower Edinburgh Cognitive and Behavioural ALS Screen ALS-Specific score (p = 0.0005). The known pathogenic SOD1 variant p.(Ile114Thr), frequently observed in the Scottish population, was detected in 9 (2.7%) of total cases but in 17.9% of familial cases. Rare variants were detected in FUS and NEK1. One individual carried both a C9orf72 expansion and SOD1 variant. CONCLUSIONS: Our results provide an accurate summary of MND demographics and genetic epidemiology. We recommend early genetic testing of people with cognitive impairment to ensure that C9orf72 carriers are given the best opportunity for informed treatment planning. Scotland is enriched for the SOD1 p.(Ile114Thr) variant and this has significant implications with regards to future genetically-targeted treatments.

Genotype-phenotype characterisation of long survivors with motor neuron disease in Scotland.

BACKGROUND: We investigated the phenotypes and genotypes of a cohort of 'long-surviving' individuals with motor neuron disease (MND) to identify potential targets for prognostication. METHODS: Patients were recruited via the Clinical Audit Research and Evaluation for MND (CARE-MND) platform, which hosts the Scottish MND Register. Long survival was defined as > 8 years from diagnosis. 11 phenotypic variables were analysed. Whole genome sequencing (WGS) was performed and variants within 49 MND-associated genes examined. Each individual was screened for C9orf72 repeat expansions. Data from ancestry-matched Scottish populations (the Lothian Birth Cohorts) were used as controls. RESULTS: 58 long survivors were identified. Median survival from diagnosis was 15.5 years. Long survivors were significantly younger at onset and diagnosis than incident patients and had a significantly longer diagnostic delay. 42% had the MND subtype of primary lateral sclerosis (PLS). WGS was performed in 46 individuals: 14 (30.4%) had a potentially pathogenic variant. 4 carried the known SOD1 p.(Ile114Thr) variant. Significant variants in FIG4, hnRNPA2B1, SETX, SQSTM1, TAF15, and VAPB were detected. 2 individuals had a variant in the SPAST gene suggesting phenotypic overlap with hereditary spastic paraplegia (HSP). No long survivors had pathogenic C9orf72 repeat expansions. CONCLUSIONS: Long survivors are characterised by younger age at onset, increased prevalence of PLS and longer diagnostic delay. Genetic analysis in this cohort has improved our understanding of the phenotypes associated with the SOD1 variant p.(Ile114Thr). Our findings confirm that pathogenic expansion of C9orf72 is likely a poor prognostic marker. Genetic screening using targeted MND and/or HSP panels should be considered in those with long survival, or early-onset slowly progressive disease, to improve diagnostic accuracy and aid prognostication.

Clinical trials in amyotrophic lateral sclerosis: a systematic review and perspective.

Amyotrophic lateral sclerosis is a progressive and devastating neurodegenerative disease. Despite decades of clinical trials, effective disease-modifying drugs remain scarce. To understand the challenges of trial design and delivery, we performed a systematic review of Phase II, Phase II/III and Phase III amyotrophic lateral sclerosis clinical drug trials on trial registries and PubMed between 2008 and 2019. We identified 125 trials, investigating 76 drugs and recruiting more than 15 000 people with amyotrophic lateral sclerosis. About 90% of trials used traditional fixed designs. The limitations in understanding of disease biology, outcome measures, resources and barriers to trial participation in a rapidly progressive, disabling and heterogenous disease hindered timely and definitive evaluation of drugs in two-arm trials. Innovative trial designs, especially adaptive platform trials may offer significant efficiency gains to this end. We propose a flexible and scalable multi-arm, multi-stage trial platform where opportunities to participate in a clinical trial can become the default for people with amyotrophic lateral sclerosis.

Experiences of remote consulting for patients and neurologists during the COVID-19 pandemic in Scotland.

BACKGROUND: Remote consulting is an emerging model in managing chronic neurological conditions and has been widely implemented during the COVID-19 pandemic. The objective of this national survey was to investigate the initial experiences of remote consulting for neurologists and patients with established neurological conditions under follow-up during the first COVID-19 phase. METHODS: In collaboration with the Scottish Association of Neurological Sciences and the Neurological Alliance of Scotland, we conducted a web-based survey of neurologists and patients between October and November 2020. FINDINGS: Data was available for 62 neurologists and 201 patients. The consensus among neurologists was that remote consulting is a satisfactory way of delivering healthcare in selected groups of patients. For practical and technical reasons, there was preference for phone over video consultations (phone 63% vs video 33%, p=0.003). The prevailing opinion among clinicians was that considerable training interventions for remote consultation skills are required ('yes' 63% vs 'no' 37%, p=0.009) to improve clinician consultation skills and successfully embed this new model of care.Most patients perceived remote consultations as safe, effective and convenient, with 89% of patients being satisfied with their remote consultation experience. Although traditional face-to-face consultations were the favoured way of interaction for 62% of patients, a significant proportion preferred that some of their future consultations be remote. INTERPRETATION: Although not a replacement for face-to-face consultations, this survey illustrates that remote consulting can be an acceptable adjunct to traditional face-to-face consultations for doctors and patients. More research is required to identify overall safety and applicability.

National audit of cognitive assessment in people with pwMND A national audit of cognitive assessment in people with motor neurone disease (pwMND) in Scotland.

Cognitive and behavioral abnormalities are recognized as an integral part of Motor Neurone Disease (MND) and occur at all stages of the disease. The early detection of cognitive and behavioral symptoms in MND is critical. Such symptoms are only reported when we explicitly ask, evaluate, document, and assess. In the National Institute for Health and Care Excellence (NICE) MND guideline (2016), formal cognitive and behavioral assessment is incorporated in MND management and is fundamental to providing appropriate care to pwMND. Cognition is explicitly stated in 14 separate recommendations in the guidelines. The NICE guidelines therefore constitute pre-defined standards which we audited. This audit highlights that health professionals increasingly recognize the significance of cognitive screening in MND and follow more structured approaches in implementing this compared to previous years.

Elderly woman with subacute lower limb weakness and rapid systemic decline.

A 74-year-old woman developed bilateral leg weakness, with fluctuating cognitive and systemic symptoms that progressed despite treatment. Her diagnosis was confirmed at autopsy. Her case was discussed at the Edinburgh Clinical Neurology Course 2019 Clinicopathological Conference.

The Prevalence and Management of Saliva Problems in Motor Neuron Disease: A 4-Year Analysis of the Scottish Motor Neuron Disease Register.

INTRODUCTION: Saliva problems are common and distressing for people with motor neuron disease (pwMND). Despite clinical guidelines for assessment and treatment, management of saliva problems has received little research attention. OBJECTIVE: We aimed to investigate the prevalence of saliva problems in pwMND, their association with clinical factors, and their management practice using a highly curated population-based register for motor neuron disease (MND) with 99% case ascertainment. METHODS: We conducted an analysis of pwMND diagnosed between January 2015 and October 2019 using the Scottish MND Register (CARE-MND [Clinical, Audit, Research, and Evaluation of MND]). The association between clinical factors and saliva problems was investigated using univariate and multivariable logistic regression; results are reported as odds ratio (OR) and 95% confidence intervals. A survey of health-care professionals involved in the care of pwMND was performed to contextualize the findings. RESULTS: 939 pwMND were included. Prevalence of saliva problems was 31.3% (294). Bulbar onset (OR 9.46 [4.7, 19.2]; p < 0.001) but not age, sex, time to diagnosis, or MND subtype were independently associated with the presence of saliva problems in multivariable regression, and 52.7% (155) of those with saliva problems received pharmacological management. The most commonly used medications were hyoscine, amitriptyline, carbocisteine, glycopyrrolate, and atropine. Evidence base (8, 72.7%) and local guidelines (10, 90.9%) were cited as the most important factors influencing treatment decision by survey respondents (n = 11). CONCLUSION: Saliva problems are common and associated with bulbar onset MND. A substantial proportion of pwMND with saliva problems did not receive recommended treatments. Future research is required to determine the relative efficacy of individual pharmacological treatments.

The TMEM106B FTLD-protective variant, rs1990621, is also associated with increased neuronal proportion.

Apart from amyloid ß deposition and tau neurofibrillary tangles, Alzheimer's disease (AD) is a neurodegenerative disorder characterized by neuronal loss and astrocytosis in the cerebral cortex. The goal of this study is to investigate genetic factors associated with the neuronal proportion in health and disease. To identify cell-autonomous genetic variants associated with neuronal proportion in cortical tissues, we inferred cellular population structure from bulk RNA-Seq derived from 1536 individuals. We identified the variant rs1990621 located in the TMEM106B gene region as significantly associated with neuronal proportion (p value = 6.40 × 10-07) and replicated this finding in an independent dataset (p value = 7.41 × 10-04) surpassing the genome-wide threshold in the meta-analysis (p value = 9.42 × 10-09). This variant is in high LD with the TMEM106B non-synonymous variant p.T185S (rs3173615; r2 = 0.98) which was previously identified as a protective variant for frontotemporal lobar degeneration (FTLD). We stratified the samples by disease status, and discovered that this variant modulates neuronal proportion not only in AD cases, but also several neurodegenerative diseases and in elderly cognitively healthy controls. Furthermore, we did not find a significant association in younger controls or schizophrenia patients, suggesting that this variant might increase neuronal survival or confer resilience to the neurodegenerative process. The single variant and gene-based analyses also identified an overall genetic association between neuronal proportion, AD and FTLD risk. These results suggest that common pathways are implicated in these neurodegenerative diseases, that implicate neuronal survival. In summary, we identified a protective variant in the TMEM106B gene that may have a neuronal protection effect against general aging, independent of disease status, which could help elucidate the relationship between aging and neuronal survival in the presence or absence of neurodegenerative disorders. Our findings suggest that TMEM106B could be a potential target for neuronal protection therapies to ameliorate cognitive and functional deficits.

The safety of using active triage to provide advice rather than a face-to-face neurology outpatient appointment.

BACKGROUND: Neurology referrals from primary care are increasing. Actively triaging referrals is one way of providing a better patient-focussed service. METHODS: We reviewed the safety and cost-effectiveness of 'advice only' rather than face-to-face appointments for neurology patients via active triage. Referrals triaged as 'advice only' were identified over a 6-month period. Data were collected on reason for referral, opinion of triaging neurologist and whether the patient re-presented to neurology within 12 months. RESULTS: A total of 10% (236 out of 2,445) of referred patients were given advice only after active triage. A total of 71% (n = 167) had no further secondary care presentations in 12 months. The most common presentation was headache (n = 57; 13%). One patient had a major diagnostic change following delayed review. CONCLUSIONS: 'Advice only' allows patients to receive timely advice and management. It appears safe and is likely to be cost effective, although further data are required on whether it provides satisfactory outcomes for patients and general practitioners.

A single-nuclei RNA sequencing study of Mendelian and sporadic AD in the human brain.

BACKGROUND: Alzheimer's disease (AD) is the most common form of dementia. This neurodegenerative disorder is associated with neuronal death and gliosis heavily impacting the cerebral cortex. AD has a substantial but heterogeneous genetic component, presenting both Mendelian and complex genetic architectures. Using bulk RNA-seq from the parietal lobes and deconvolution methods, we previously reported that brains exhibiting different AD genetic architecture exhibit different cellular proportions. Here, we sought to directly investigate AD brain changes in cell proportion and gene expression using single-cell resolution. METHODS: We generated unsorted single-nuclei RNA sequencing data from brain tissue. We leveraged the tissue donated from a carrier of a Mendelian genetic mutation, PSEN1 p.A79V, and two family members who suffer from sporadic AD, but do not carry any autosomal mutations. We evaluated alternative alignment approaches to maximize the titer of reads, genes, and cells with high quality. In addition, we employed distinct clustering strategies to determine the best approach to identify cell clusters that reveal neuronal and glial cell types and avoid artifacts such as sample and batch effects. We propose an approach to cluster cells that reduces biases and enable further analyses. RESULTS: We identified distinct types of neurons, both excitatory and inhibitory, and glial cells, including astrocytes, oligodendrocytes, and microglia, among others. In particular, we identified a reduced proportion of excitatory neurons in the Mendelian mutation carrier, but a similar distribution of inhibitory neurons. Furthermore, we investigated whether single-nuclei RNA-seq from the human brains recapitulate the expression profile of disease-associated microglia (DAM) discovered in mouse models. We also determined that when analyzing human single-nuclei data, it is critical to control for biases introduced by donor-specific expression profiles. CONCLUSION: We propose a collection of best practices to generate a highly detailed molecular cell atlas of highly informative frozen tissue stored in brain banks. Importantly, we have developed a new web application to make this unique single-nuclei molecular atlas publicly available.

Ictal asystole: a diagnostic and management conundrum.

We report two cases of adults presenting with transient loss of consciousness (TLoC) followed by a rapid recovery. Careful history taking revealed a stereotyped prodrome of déjà vu, raising the possibility of these events being focal seizures rather than syncope. The patients were commenced on antiepileptic drugs (AEDs) at the same time as having cardiac monitoring organised. This confirmed asystole during the seizure symptoms, resulting in TLoC. It was assumed that the cardiac arrhythmia explained the entire picture, a permanent pacemaker (PPM) was inserted, and the AEDs were withdrawn in one patient and not commenced in the other. However, they both subsequently presented with worsening seizures, including generalised tonic-clonic seizures, despite a functioning pacemaker. The seizures improved on restarting AEDs. The cases illustrate the diagnostic and management difficulties of patients presenting with ictal asystole, a condition that requires input from various medical specialities. There is no strong evidence base for the management of ictal asystole, but we favour a combined approach of AEDs and PPM insertion.

Clinical audit research and evaluation of motor neuron disease (CARE-MND): a national electronic platform for prospective, longitudinal monitoring of MND in Scotland.

Objectives: Launched in 1989, the Scottish Motor Neuron Disease Register (SMNDR) has provided a resource for prospective clinical data collection. However, in 2015 we aimed to evolve a system to allow: i) A patient-centered approach to care based on recognized standards, ii) Harmonized data sharing between Scottish health professionals in "real-time", iii) Regular audit of care to facilitate timely improvements in service delivery, and iv) Patient participation in a diverse range of observational and interventional research studies including clinical trials. Methods: We developed a standardized national electronic data platform-Clinical Audit Research and Evaluation of MND (CARE-MND) which integrates clinical audit and research data fields. Data completion pre- and post-CARE-MND were compared, guided by recently published National Institute for Clinical Excellence (NICE) recommendations. Statistical difference in data capture between time periods was assessed using Z-test of proportions. Results: Data field completion for the historical 2011-2014 period ranged from 4 to 95%; median 50%. CARE-MND capture ranged from 32 to 98%; median 87%. 15/17 fields were significantly more complete post-CARE-MND (p < 0.001). All MND nurse/allied health specialists in Scotland use the CARE-MND platform. Management of MND in Scotland is now coordinated through a standardized template. Conclusions: Through CARE-MND, national audits of MND care and interventions have been possible, leading to protocols for harmonized service provision. Stratification of the MND population is facilitating participation in observational and interventional studies. CARE-MND can act as a template for other neurological disorders.

Changing epidemiology of motor neurone disease in Scotland.

OBJECTIVES: Scotland benefits from an integrated national healthcare team for motor neurone disease (MND) and a tradition of rich clinical data capture using the Scottish MND Register (launched in 1989; one of the first national registers). The Scottish register was re-launched in 2015 as Clinical Audit Research and Evaluation of MND (CARE-MND), an electronic platform for prospective, population-based research. We aimed to determine if incidence of MND is changing over time. METHODS: Capture-recapture methods determined the incidence of MND in 2015-2016. Incidence rates for 2015-2016 and 1989-1998 were direct age and sex standardised to allow time-period comparison. Phenotypic characteristics and socioeconomic status of the cohort are described. RESULTS: Coverage of the CARE-MND platform was 99%. Crude incidence in the 2015-2017 period was 3.83/100,000 person-years (95% CI 3.53-4.14). Direct age-standardised incidence in 2015 was 3.42/100,000 (95% CI 2.99-3.91); in 2016, it was 2.89/100,000 (95% CI 2.50-3.34). The 1989-1998 direct standardised annual incidence estimate was 2.32/100,000 (95% CI 2.26-2.37). 2015-2016 standardised incidence was 66.9% higher than Northern European estimates. Socioeconomic status was not associated with MND. CONCLUSIONS: Our data show a changing landscape of MND in Scotland, with a rise in incidence by 36.0% over a 25-year period. This is likely attributable to ascertainment in the context of improved neurological services in Scotland. Our data suggest that CARE-MND is a reliable national resource and findings can be extrapolated to the other Northern European populations.

How to do it: the clinicopathological conference.

The prime purpose of the clinicopathological conference (CPC) is education, delivered ideally in an entertaining and engaging manner. This article tackles both how to organise a CPC (more challenging than it might appear) and how to survive as a CPC discussant (always challenging). The patient at the heart of the CPC will have had a challenging and difficult illness. The reanalysis of the clinical presentation by the discussant, a re-exploration of their clinical journey, is the key to the educational value of the CPC rather than the ultimate diagnosis. A well-delivered CPC is the pinnacle of educational events in neurology, and this article highlights some useful tips on both sides of the divide.

Clinicopathological case: rapid cognitive decline and myoclonus associated with fever, arthropathy and scleritis.

A 65-year-old man presented with transient neurological symptoms, followed by rapid cognitive decline, myoclonus and fevers. He had evidence of scleritis and an arthropathy. This paper reports the clinicopathological conference discussed at the Association of British Neurologists Annual Meeting 2017.

How to do it: investigate exertional rhabdomyolysis (or not).

Rhabdomyolysis is the combination of symptoms (myalgia, weakness and muscle swelling) and a substantial rise in serum creatine kinase (CK) >50 000 IU/L; there are many causes, but here we specifically address exertional rhabdomyolysis. The consequences of this condition can be severe, including acute kidney injury and requirement for higher level care with organ support. Most patients have 'physiological' exertional rhabdomyolysis with no underlying disease; they do not need investigation and should be advised to return to normal activities in a graded fashion. Rarely, exertional rhabdomyolysis may be the initial presentation of underlying muscle disease, and we review how to identify this much smaller group of patients, who do require investigation.