Spinal bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by a polyglutamine repeat expansion in the androgen receptor gene (AR). Lower motor neuron loss is a key feature of the disease, yet it remains poorly understood why these cells are affected. The transcriptional mechanisms underlying SBMA pathogenesis and how these evolve across developmental and disease stages remains incompletely defined. To elucidate the molecular mechanisms underlying motor neuron loss in SBMA, we first performed transcriptomic profiling of both induced pluripotent stem cell derived motor neurons (iPSC-MNs) generated from SBMA patients and laser-captured micro dissected motor neurons (LCM-MNs) from symptomatic AR100 SBMA mice. We compared differential gene expression between the two models to identify shared transcriptional programs. To address the temporal progression of molecular changes we conducted profiling at key stages of motor neurogenesis in the developing iPSC-MNs and at pre-symptomatic and end-stage disease in AR100 SBMA mice to elucidate the emergence of the transcriptional phenotype and the trajectory of the gene expression changes. We found significant transcriptional convergence between these two species. Notably, shared dysregulation was observed in pathways related to the spliceosome, the cell cycle and mitochondrial function. These transcriptional alterations emerged early in motor neurogenesis suggesting a developmental component to SBMA. Further in AR100 LCM-MNs we also observed disruption of mitochondrial and DNA damage repair pathways from pre-symptomatic to end stage disease. This study identifies conserved pathogenic mechanisms across two SBMA model systems and provides crucial insights into the molecular basis and temporal dynamics of SBMA progression which may help identify potential therapeutic targets for SBMA. ![Figure][1] ### Competing Interest Statement The authors have declared no competing interest. * SBMA : Spinal bulbar muscular atrophy AR : androgen receptor polyQ : polyglutamine iPSCs : induced pluripotent stem cells MNs : motor neurons, mouse model, mitochondria DDR : DNA damage response ALS : amyotrophic lateral sclerosis DHT : dihydrotestosterone, time-series, MultiRNAflow MRC [1]: pending:yes

Background The m.3243A>G mitochondrial DNA variant is the most common cause of adult mitochondrial disease and is associated with a heterogeneous clinical phenotype. The retina and optic nerve are among the most metabolically active tissues, making them vulnerable to mitochondrial dysfunction. Optical coherence tomography (OCT) studies have demonstrated retinal nerve fibre layer (RNFL) thinning in mitochondrial and other neurodegenerative diseases. We investigated whether temporal RNFL thinning is associated with central nervous system (CNS) involvement in individuals with the m.3243A>G variant.Methods High-resolution OCT was used to assess peripapillary RNFL thickness and perform macular segmentation. Participants were categorised into normal RNFL (n=14) or temporal RNFL thinning (n=15) groups. Demographic data, mean-corrected m.3243A>G heteroplasmy, Newcastle Mitochondrial Disease Adult Scale (NMDAS) scaled scores and NMDAS neurological traits were compared.Results Temporal RNFL thinning was significantly associated with neurological features (Fisher’s exact test, p=0.027). In multivariable analysis, RNFL thinning and age were independent predictors of neurological involvement. Macular OCT revealed concomitant thinning of the ganglion cell-inner plexiform (GC-IPL) complex in the RNFL thinning group, with preservation of outer retinal layers, supporting primary retinal ganglion cell vulnerability. No significant associations were found between RNFL thinning and m.3243A>G heteroplasmy or NMDAS scaled scores.Conclusion Temporal RNFL thinning, accompanied by GC-IPL loss, is associated with neurological involvement in m.3243A>G-related mitochondrial disease, supporting its potential as a non-invasive biomarker of CNS dysfunction. Longitudinal studies are needed to determine whether these retinal changes are progressive and predictive of neurological decline.

A 57-year-old man developed worsening early morning headaches, muscle cramps and falls over 12 months. He had widespread fasciculation and was diagnosed with motor neurone disease, and treated with nocturnal hypoventilation. Based on this diagnosis, he made significant personal and financial decisions including retiring and selling his house. He subsequently developed a lump in his right breast and was found to have gynaecomastia. This triggered genetic testing for Kennedy's disease leading to the correct diagnosis. This case highlights an unusual presentation of a rare disease leading to misdiagnosis and major repercussions for the patient. Recent genetic analysis from the 100 000 genome project suggests Kennedy's disease may be four times more prevalent in the population than previously thought, highlighting the need to consider genetic testing, especially if there is a suggestion of multisystem disease.

Devine et al. argue that recent changes to clinical neurology training in the UK have the potential to exacerbate an existing crisis in academic neurology, and discuss what might be done to remedy the situation.

Introduction Guillain-Barré Syndrome (GBS) is an acute, inflammatory polyradiculoneuropathy causing sensory, motor and autonomic nerve dysfunction. Dysautonomia is reported in up to 60%, however, guidance for dysautonomia monitoring in GBS is lacking. Methods Retrospective cohort study of incident GBS to 4 UK Neuroscience centres: December 2019 -October 2022. Published criteria were used to verify diagnosis and identify autonomic dysfunction. Data i was collected from observation charts and medical records. Results 47 patients were included, mean age 54.3yrs (SD 15.9), 64% male. 56% AIDP, 26% AMSAN/AMAN, i or GBS variants. Mean mEGOS score was 5 (SD 3.4), mean length of stay 32.5 days (SD 25.7 days). 34% required ITU care, 23% invasive ventilation. 45 patients (95%) had at least one feature of dysautonomia. Gastrointestinal (96%), urinary (68%) and pupillary (72%) abnormalities were screened for more often than postural BP (32%), baseline ECG (38%), or cardiac monitoring (47%). Observations met criteria for cardiovascular dysautonomia without medical documentation in 27/32 cases with labile BP, 11/26 with persistent tachy/bradycardia, 6/18 with persistent hypertension. Conclusion Medical awareness of dysautonomia (notably cardiovascular dysautonomia) in GBS is sub- optimal in UK Neurology. Improving dysautonomia care could impact patient experience and, in rare cases, save lives.

Pain is common in the acute phase in Guillain-Barré syndrome (GBS), affecting 66% in a large Dutch cohort, with 43% experiencing distal neuropathic pain in the first three weeks. We aimed to ascertain the frequency, and treatment of acute distal neuropathic pain in the first two weeks of admission of a multicentre UK GBS cohort. We performed a retrospective cohort study of incident GBS to 4 neuroscience centres December 2019 and April 2022. We collected data on demographics, GBS subtype, and the presence of distal limb neu- ropathic pain and its pharmacological management. 47 patients were included, mean age 54.3yrs (SD 15.9), 64% male. 56% AIDP, 26% AMSAN/AMAN, or GBS variants. Mean mEGOS score was 5 (SD 3.4), mean length of stay 32.5 days (SD 25.7 days). 34% required ITU care, 23% required invasive ventilation. Neuropathic pain was experienced by 78.7% (37) of patients within the first 2 weeks, of which 70.2% (33) received at least 1 neuropathic pain agent. There was no correlation of the presence of neuropathic pain with GBS severity or subtype. There was a high frequency of acute neuropathic pain, compared to previous cohorts. 28.2% of patients were untreated, highlighting the importance of ongoing assessment.

Introduction and AimsAccurate prognostication for comatose patients following out of hospital cardiac arrests (OOHCA) remains challenging. This study aimed to evaluate the use of CT-scans and EEGs for neuro-prognostication in comatose OOHCA patients admitted to ICU in 2 major cardiac centres.MethodsRecords of 71 patients admitted to ICU following OOHCA in 2019 were reviewed. Use of CT-scans and EEGs were compared with the European Resuscitation Council (ERC) guidelines.Results46 (64.8%) patients had withdrawal of life support (WLS) during admission. 60 (84.5%) patients had reported CT-brains, of which 26.7% showed either generalised oedema or a loss of grey-white matter distinction and 73.3% showed other ischaemic changes or normal results. 100% of patients with general- ised oedema or a loss of distinction and 59.1% patients with other ischaemic changes or normal scans had WLS during admission. EEGs were performed in 21 patients (29.6%), 18 (85.7%) of which had WLS. 22 (31.0%) patients had WLS within 72 hours of arrest. 90.9% of these patients had CT-heads and 0% had EEGs performed.ConclusionEEGs were used infrequently for neuro-prognostication and cerebral oedema and a loss of grey-white matter distinction were more often associated with WLS.

BackgroundThe m.3243A>G mtDNA is the most common pathogenic mtDNA variant and has a very varied clinical phenotype. Vision has a high metabolic demand and there are large numbers of mito- chondria in the retina, particularly in the photoreceptors and the retinal pigmented epithelial layer. Little is known about the heteroplasmic/phenotypic correlations of retinopathy in patients with m.3243A>G- related mitochondrial disease.ObjectiveThe overall aim of the study was to explore retinal involvement in patients with m.3243A>G- related mitochondrial disease. Specifically, to describe the retinal and optic nerve changes and to determine whether the presence of maculopathy and/or optic nerve changes predict the development of CNS involvement in patients with the m.3243A>G mutationMethodsPatients with genetically confirmed m.3243A>G-related mitochondrial disease were identified from the UK Mitochondrial Disease Patient Cohort; a registry of patients under active follow up at one of the three UK Mitochondrial Centres (Newcastle, London and Oxford). Participants underwent detailed clinical and ophthalmological examination. Ophthalmological phenotype was correlated with a validated clinical rating scale score (NMDAS) and m.3243A>G heteroplasmy levels.ResultsRetinal defects were common in m.3243A>G-related mitochondrial disease with subgroups of patients demonstrating maculopathy or optic nerve involvement.ConclusionCharacteristic retinal defects are common in m.3243A>G-related mitochondrial disease.

Getting It Right First Time (GIRFT) Neurology recommended in September 2021 to audit the site of death of patients with motor neurone disease (MND) as an indicator for whole-life management.This retrospective audit collected data on patients with MND admitted to Croydon University Hospital during a 2-year period from April 2018. Site of death is currently not recorded so data were obtained from the multi-disciplinary team. As per NICE guidelines, data were extracted on documentation of discussions regarding resuscitation status.Of the 20 patients admitted, 12 died. Compared to national statistics, more patients died at home (42% locally vs 27% nationally), with fewer dying in hospital (17% vs 39% nationally) and similar proportions dying in a hospice (~15%). In 8 of the 17 non-elective admissions, patients had their resuscitation status clearly documented before or during the admission.Patients with MND at Croydon are being managed appropriately compared to national data. Systems like Coordinate My Care enable communication between primary and secondary care settings and should be used consistently. Site of death is to be documented in Model Hospital enabling easier audit of this in the future.

A 23-year-old female was admitted to ED two weeks after delivery with severe migrainous headaches and a painful pupil-sparing partial right third nerve palsy presenting as diplopia on upward and lateral gaze and a partial ptosis. This was the third such presentation for her as she was diagnosed with oph- thalmoplegic migraine (OM) since 8 years old. A second episode at the 18 years of age required steroid treatment due to a delayed recovery for few months. Repeat orbit MRI confirmed slightly grown lesion on the right oculomotor nerve compared scans 4 years apart appearing as a thickened nodular enhancement between the P1 segment and superior cerebel- lar artery. Multiple neuro-oncology and neuro-radiology MDTs confirmed this lesion to be an oculomotor nerve schwannoma. She had to be treated with steroids due to deficits and 2 months later while migrain- ous headache was fully resolved, she was still left with subtle upward and lateral gaze diplopia. She will have surveillance imaging and follow up. Recurrent Painful Ophthalmoplegic Neuropathy (RPON) is replacing OM and expected to be associated with a resolution of the enhancement. Schwannomas on the other hand are known to be growing during pregnancy and affected by hormonal changes. Transient or recurrent oculomotor nerve deficits may be the primary manifestations of cranial nerve schwannoma and we hypothesise this tumour being the cause of her RPON which must be considered in OM.

Background Spinal bulbar muscular atrophy is a slowly progressive neurodegenerative disease which affects lower motor neurons (MNs). It is caused by a trinucleotide polyglutamine (CAG) repeat expansion in the androgen receptor (AR) gene but the precise mechanisms of degeneration of the MNs in SBMA are complex and remain poorly understood. There are currently no available treatments for patients. Objectives The aim of this study was to develop a human iPSC model of SBMA patient MNs in order to characterise early transcriptomic events in SBMA. Methods Human iPSCs were differentiated into spinal MNs using an established, developmentally-rational- ised protocol. Samples were collected at key stages in motor neurogenesis for RNA-sequencing followed by transcriptomic and splicing analysis. Live-cell imaging assays for mitochondrial membrane potential and axonal transport of mitochondria and signal endosomes were performed to validate transcriptomic findings. Results Over-representation analysis of differentially expressed genes revealed enrichment of DNA damage response and cell cycle pathways. There were reduced transcripts of genes involved in mito- chondrial pathways with reduced mitochondrial membrane potential and anterograde mitochondrial transport in SBMA on live-cell imaging. Alternative splicing events were common and involved adherens junction and extracellular matrix pathways. Conclusion Early transcriptional dysregulation, alternative splicing and mitochondrial dysfunction were seen in SBMA MNs as well as genes linked to defective p53/DNA damage response and the cell cycle. These cellular phenotypes offer potential targets for future clinical treatments.

Histopathological analysis of tissue sections is invaluable in neurodegeneration research. However, cell‐to‐cell variation in both the presence and severity of a given phenotype is a key limitation of this approach, reducing the signal to noise ratio and leaving unresolved the potential of single‐cell scoring for a given disease attribute. Here, we tested different machine learning methods to analyse high‐content microscopy measurements of hundreds of motor neurons (MNs) from amyotrophic lateral sclerosis (ALS) post‐mortem tissue sections. Furthermore, we automated the identification of phenotypically distinct MN subpopulations in VCP‐ and SOD1‐mutant transgenic mice, revealing common morphological cellular phenotypes. Additionally we established scoring metrics to rank cells and tissue samples for both disease probability and severity. By adapting this paradigm to human post‐mortem tissue, we validated our core finding that morphological descriptors robustly discriminate ALS from control healthy tissue at single cell resolution. Determining disease presence, severity and unbiased phenotypes at single cell resolution might prove transformational in our understanding of ALS and neurodegeneration more broadly.

SUMMARYHistopathological analysis of tissue sections is an invaluable resource in neurodegeneration research. Importantly, cell-to-cell variation in both the presence and severity of a given phenotype is however a key limitation of this approach, reducing the signal to noise ratio and leaving unresolved the potential of single-cell scoring for a given disease attribute. Here, we developed an image processing pipeline for automated identification and profiling of motor neurons (MNs) in amyotrophic lateral sclerosis (ALS) pathological tissue sections. This approach enabled unbiased analysis of hundreds of cells, from which hundreds of features were readily extracted. Next by testing different machine learning methods, we automated the identification of phenotypically distinct MN subpopulations in VCP- and SOD1-mutant transgenic mice, revealing common aberrant phenotypes in cellular shape. Additionally we established scoring metrics to rank cells and tissue samples for both disease probability and severity. Finally, by adapting this methodology to human post-mortem tissue analysis, we validated our core finding that morphological descriptors strongly discriminate ALS from control healthy tissue at the single cell level. In summary, we show that combining automated image processing with machine learning methods substantially improves the speed and reliability of identifying phenotypically diverse MN populations. Determining disease presence, severity and unbiased phenotypes at single cell resolution might prove transformational in our understanding of ALS and neurodegenerative diseases more broadly.

Multichannel microscopy data from histopathological sections of 1/ Tissue sections from spinal cord of SOD1- and VCP-mutant ALS mouse models together with control immunolabeled for FUS, SFPQ, ChAT and counterstained with DAPI. 2/ Tissue sections from spinal cord of Healthy and sporadic ALS donors immunolabeled for FUS or SFPQ, ChAT and counterstained with DAPI. 3/ Scripts to preprocess these images. These two series of multichannel fluorescent microscopy data have been used in several manuscripts including: Luisier R, Tyzack GE, Hall CE, Mitchell JS, Devine H, Taha DM, et al. Intron retention and nuclear loss of SFPQ are molecular hallmarks of ALS. Nat Commun 2018; 9: 2010. Tyzack GE, Luisier R, Taha DM, Neeves J, Modic M, Mitchell JS, et al. Widespread FUS mislocalization is a molecular hallmark of amyotrophic lateral sclerosis. Brain 2019; 142: 2572–80.

The majority of neuroscience research has focused on nerve cells called neurons. But there are just as many star-shaped cells called astrocytes in the brain. In this article, we discuss how astrocytes have many really important roles for keeping neurons healthy. We also describe how scientists are using stem cell technology to study human astrocytes and how astrocytes go wrong in neurodegenerative diseases like Alzheimer’s disease, Parkinson’s disease, and motor neuron disease.

Spinal and bulbar muscular atrophy (SBMA) results from a CAG repeat expansion within the androgen receptor gene (AR). It is unclear why motor neurons selectively degenerate and there are currently no treatments for this debilitating disease. To uncover the causative genes and pathways involved in motor neuron dysfunction, we undertook transcriptomic profiling of primary embryonic motor neurons from SBMA mice. We show that transcriptional dysregulation occurs early during development in SBMA motor neurons. One gene found to be dysregulated, Chmp7, was also altered in vivo in spinal cord before symptom onset in SBMA mice, and crucially in motor neuron precursor cells derived from SBMA patient stem cells, suggesting that Chmp7 may play a causal role in disease pathogenesis by disrupting the endosome-lysosome system. Furthermore, genes were enriched in SBMA motor neurons in several key pathways including p53, DNA repair, WNT and mitochondrial function. SBMA embryonic motor neurons also displayed dysfunctional mitochondria along with DNA damage, possibly resulting from DNA repair gene dysregulation and/or mitochondrial dysfunction. This indicates that a coordinated dysregulation of multiple pathways leads to development of SBMA. Importantly, our findings suggest that the identified pathways and genes, in particular Chmp7, may serve as potential therapeutic targets in SBMA.