Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting primarily the motor system, but in which extra‐motor manifestations are increasingly recognized. The loss of upper and lower motor neurons in the motor cortex, the brain stem nuclei and the anterior horn of the spinal cord gives rise to progressive muscle weakness and wasting. ALS often has a focal onset but subsequently spreads to different body regions, where failure of respiratory muscles typically limits survival to 2–5 years after disease onset. In up to 50% of cases, there are extra‐motor manifestations such as changes in behaviour, executive dysfunction and language problems. In 10%–15% of patients, these problems are severe enough to meet the clinical criteria of frontotemporal dementia (FTD). In 10% of ALS patients, the family history suggests an autosomal dominant inheritance pattern. The remaining 90% have no affected family members and are classified as sporadic ALS. The causes of ALS appear to be heterogeneous and are only partially understood. To date, more than 20 genes have been associated with ALS. The most common genetic cause is a hexanucleotide repeat expansion in the C9orf72 gene, responsible for 30%–50% of familial ALS and 7% of sporadic ALS. These expansions are also a frequent cause of frontotemporal dementia, emphasizing the molecular overlap between ALS and FTD. To this day there is no cure or effective treatment for ALS and the cornerstone of treatment remains multidisciplinary care, including nutritional and respiratory support and symptom management. In this review, different aspects of ALS are discussed, including epidemiology, aetiology, pathogenesis, clinical features, differential diagnosis, investigations, treatment and future prospects.

Background:  The evidence base for the diagnosis and management of amyotrophic lateral sclerosis (ALS) is weak.Objectives:  To provide evidence‐based or expert recommendations for the diagnosis and management of ALS based on a literature search and the consensus of an expert panel.Methods:  All available medical reference systems were searched, and original papers, meta‐analyses, review papers, book chapters and guidelines recommendations were reviewed. The final literature search was performed in February 2011. Recommendations were reached by consensus.Recommendations:  Patients with symptoms suggestive of ALS should be assessed as soon as possible by an experienced neurologist. Early diagnosis should be pursued, and investigations, including neurophysiology, performed with a high priority. The patient should be informed of the diagnosis by a consultant with a good knowledge of the patient and the disease. Following diagnosis, the patient and relatives/carers should receive regular support from a multidisciplinary care team. Medication with riluzole should be initiated as early as possible. Control of symptoms such as sialorrhoea, thick mucus, emotional lability, cramps, spasticity and pain should be attempted. Percutaneous endoscopic gastrostomy feeding improves nutrition and quality of life, and gastrostomy tubes should be placed before respiratory insufficiency develops. Non‐invasive positive‐pressure ventilation also improves survival and quality of life. Maintaining the patient’s ability to communicate is essential. During the entire course of the disease, every effort should be made to maintain patient autonomy. Advance directives for palliative end‐of‐life care should be discussed early with the patient and carers, respecting the patient’s social and cultural background.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons.