510 Shepheard SR, et al. J Neurol Neurosurg Psychiatry 2021;92:510–518. doi:10.1136/jnnp-2020-325014 Original research Value of systematic genetic screening of patients with amyotrophic lateral sclerosis Stephanie R Shepheard , 1 Matthew D Parker, 1 Johnathan Cooper-Knock , 1 Nick S Verber, 1 Lee Tuddenham, 1 Paul Heath, 1 Nick Beauchamp, 2 Elsie Place, 2 Elizabeth S A Sollars, 2 Martin R Turner , 3 Andrea Malaspina, 4 Pietro Fratta, 5,6 Channa Hewamadduma, 7 Thomas M Jenkins , 1 Christopher J McDermott , 1 Dennis Wang, 8 Janine Kirby, 1 Pamela J Shaw , 1,7 on behalf of the Project MINE Consortium Neurodegeneration To cite: Shepheard SR, Parker MD, Cooper-Knock J, et al. J Neurol Neurosurg Psychiatry 2021;92:510–518. ► Additional material is published online only. To view, please visit the journal online (http://dx.doi.org/10.1136/ jnnp-2020-325014). For numbered affliations see end of article. Correspondence to Professor Pamela J Shaw, Sheffeld Institute for Translational Neuroscience, The University of Sheffeld, Sheffeld, Sheffeld, UK; pamela.shaw@ sheffeld.ac.uk SRS, MDP and JC-K contributed equally. JK and PJS are joint senior authors. Received 1 September 2020 Revised 15 November 2020 Accepted 25 November 2020 Published Online First 14 February 2021 © Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ. ABSTRACT Objective The clinical utility of routine genetic sequencing in amyotrophic lateral sclerosis (ALS) is uncertain. Our aim was to determine whether routine targeted sequencing of 44 ALS-relevant genes would have a signifcant impact on disease subclassifcation and clinical care. Methods We performed targeted sequencing of a 44- gene panel in a prospective case series of 100 patients with ALS recruited consecutively from the Sheffeld Motor Neuron Disorders Clinic, UK. All participants were diagnosed with ALS by a specialist Consultant Neurologist. 7/100 patients had familial ALS, but the majority were apparently sporadic cases. Results 21% of patients with ALS carried a confrmed pathogenic or likely pathogenic mutation, of whom 93% had no family history of ALS. 15% met the inclusion criteria for a current ALS genetic-therapy trial. 5/21 patients with a pathogenic mutation had an additional variant of uncertain signifcance (VUS). An additional 21% of patients with ALS carried a VUS in an ALS- associated gene. Overall, 13% of patients carried more than one genetic variant (pathogenic or VUS). Patients with ALS carrying two variants developed disease at a signifcantly earlier age compared with patients with a single variant (median age of onset=56 vs 60 years, p=0.0074). Conclusions Routine screening for ALS-associated pathogenic mutations in a specialised ALS referral clinic will impact clinical care in 21% of cases. An additional 21% of patients have variants in the ALS gene panel currently of unconfrmed signifcance after removing non- specifc or predicted benign variants. Overall, variants within known ALS-linked genes are of potential clinical importance in 42% of patients. INTRODUCTION Amyotrophic lateral sclerosis (ALS) is an adult- onset neurodegenerative disease characterised by progressive injury and cell death of upper and lower motor neurons in the motor cortex, brainstem and spinal cord. This leads to progressive failure of the neuromuscular system with death, usually from respiratory failure, within 2–5 years of symptom onset in most cases. Up to 50% of cases also show mild cognitive impairment, with approximately 5% progressing to clinically recognised fronto- temporal dementia (FTD). 1 While the majority of ALS cases are considered sporadic (sALS), 5%–10% have been shown to be familial, usually with auto- somal dominant inheritance, and the genetic cause of approximately 60%–70% of familial ALS (fALS) cases has now been identified. 2 The most common genetic cause of ALS is due to expansion of a GGGGCC (G4C2) hexanucleotide repeat in the first intron of the C9orf72 gene. This expansion has a frequency of 43% in fALS and 7% in sALS cases in our UK cohort, 3 which is comparable with worldwide figures of 39.3% for fALS and 7.0% for sALS. 4 Mutations in SOD1, 5 6 TARDBP, 5 7 8 and FUS 5 9 genes, the next most common genetic causes of ALS, have also been reported in both patients with fALS and those with sALS. Therefore, it is clear that apparently sporadic cases can also carry poten- tially pathogenic variants in known ALS genes. In a recent study which screened 17 ALS-related genes, 27.8% of apparently sporadic cases carried a potentially pathogenic or rare variant in a known ALS gene. 10 In addition, it was noted that 3.8% of patients also carried multiple variants, with these cases having a significantly earlier age of onset. Another recent report from an Australian sporadic ALS cohort found that one-third of patients carried a variant of interest and 7% carried two or more variants, which again was correlated with an earlier age of onset. 11 It has previously been reported that ALS is a six-step process, with genes, environment and time (in the form of ageing) contributing to disease development. 12 It was proposed that indi- viduals with a genetic variant would require fewer steps than those without such variants. Using data from an ALS registry in Italy, this proved to be the case, with individuals carrying C9orf72, TARDBP or SOD1 mutations showing a three-step, four-step and two-step process. 13 Currently, only cases with a familial history of ALS, dementia or with a young age of disease onset tend to be routinely offered genetic screening in a clinical setting, at least in the UK. 14 However, with the advent of therapies targeting specific genetic forms of the disease associated with SOD1 or C9orf72 mutations (Biogen sponsored clinical trials Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from Protected by copyright. on August 9, 2021 at UCL Library Services. http://jnnp.bmj.com/ J Neurol Neurosurg Psychiatry: first published as 10.1136/jnnp-2020-325014 on 14 February 2021. Downloaded from