Evidence-based consensus guidelines for ALS genetic testing and counseling

How the prospect of a clinical trial impacts decision-making for predictive genetic testing in ALS

Objective: Genetic testing practices are rapidly evolving for people living with, or at-risk for, amyotrophic lateral sclerosis (ALS), due to emerging genotype-driven therapies. This study explored how individuals at-risk for familial ALS (fALS) perceive the opportunity to participate in a clinical trial, and to better understand how that may influence the decision-making process for predictive genetic testing. Methods: This study used both quantitative and qualitative data analyses. Data were collected through an online questionnaire, followed by semi-structured interviews conducted with twelve (n = 12) individuals at-risk for either SOD1- or C9orf72-ALS who had predictive testing prior to study participation. Interview data were analyzed using reflexive thematic analysis. Results: Three overarching themes were conceptualized from the data: i) the psychosocial impact of fALS; ii) perspectives of at-risk individuals on research involvement; and iii) predictive genetic counseling and testing considerations. These results contribute perspectives of the lived experience to inform predictive genetic counseling and testing practices for individuals at-risk for fALS. Conclusion: Individuals at-risk for fALS view potential participation in a presymptomatic clinical trial as an actionable measure that may increase their desire for predictive genetic testing. Genetic counseling was identified as a critical component of the predictive testing process given the life-changing implications associated with a positive result. Increased access to predictive genetic counseling, and in a timely manner, is a significant need in the ALS population given potential access to gene-specific therapies in the presymptomatic stage.

Nutritional Interventions in Amyotrophic Lateral Sclerosis: From Ketogenic Diet and Neuroprotective Nutrients to the Microbiota-Gut-Brain Axis Regulation

Amyotrophic lateral sclerosis (ALS) is a complex neurodegenerative disease with significant challenges in diagnosis and treatment. Recent research has highlighted the complex nature of ALS, encompassing behavioral impairments in addition to its neurological manifestations. While several medications have been approved to slow disease progression, ongoing research is focused on identifying new therapeutic targets. The current review focuses on emerging therapeutic strategies and personalized approaches aimed at improving patient outcomes. Recent advancements highlight the importance of targeting additional pathways such as mitochondrial dysfunction and neuroinflammation to develop more effective treatments. Personalized medicine, including genetic testing and biomarkers, is proving valuable in stratifying patients and tailoring treatment options. Complementary therapies, such as nutritional interventions like the ketogenic diet and microbiome modulation, also show promise. This review emphasizes the need for a multidisciplinary approach that integrates early diagnosis, targeted treatments, and supportive care to address the multisystemic nature of ALS and improve the quality of life for patients.

Exploring the needs and preferences of people with amyotrophic lateral sclerosis (ALS) when making genomic testing decisions: an interview study

Objective: Whole Genome Sequencing (WGS) for amyotrophic lateral sclerosis (ALS) (also known as motor neuron disease, MND) raises multiple considerations and has a range of implications for individuals and their family. However, it is unclear what needs people with ALS have when making genomic testing decisions. This study explores the experiences, needs and preferences of these individuals when considering WGS and going through the process. Methods: A semi-structured interview study was carried out with 14 people with ALS from across the UK who had, or were considering, WGS. Participants were recruited from a local ALS care center and MND Association/MND Scotland channels. Data were analyzed using framework analysis. Results: Findings indicate variation in (a) how WGS and access to pretest genetic counseling is provided, (b) the perceived adequacy of information to support decision-making and prepare people with ALS for their test result and its consequences, and (c) preferences for making decisions with family and health professionals that best meets their clinical and life needs along the care pathway. Conclusions: There is an urgent need for people with ALS to have relevant, accurate and accessible information that supports proactively their decision-making around WGS, particularly in the context of genetically-targeted treatments and clinical trials. These findings will contribute to the development of a shared decision-making intervention supporting people with ALS to make genomic testing decisions with their family and neurology services.

Individuals' experiences in genetic counseling and predictive testing for familial amyotrophic lateral sclerosis

As clinical genetic testing in the amyotrophic lateral sclerosis (ALS) diagnostic setting increases, the identification of at-risk family members has also expanded. No practice guidelines specifically for predictive genetic testing exist, and few studies about the psychological impacts of testing in this subgroup have occurred, limiting the ability to tailor recommendations and counseling in this community. We surveyed asymptomatic individuals at risk for inheriting an ALS-associated gene mutation. The 80-question survey was designed using a combination of validated measures (General Anxiety Disorder; FACToR; Decision Regret Scale) and original items. Ninety participants completed the survey, including those who completed predictive genetic testing (N = 42) and those who did not (N = 48). Gene positive individuals experienced greater negativity, uncertainty, and overall psychological impairment (p = 0.002; p < 0.001; p = 0.001). Individuals who had not undergone testing reported thinking about their risk multiple times per day and experiencing more decisional regret than those who tested (p = 0.006). In terms of decision-making, being prepared for potential clinical drug trials was a more important potential benefit among those who underwent testing (p = 0.026). Participants valuing preparedness for clinical drug trials supports the concept that genetic testing for ALS will increase as research in gene-targeted therapeutics progresses. This study describes factors relevant to the genetic testing decision-making process and adaptation to results from the perspective of at-risk individuals, which can ultimately guide genetic counseling practice in this population.

Tofersen treatment leads to sustained stabilization of disease in SOD1 ALS in a "real-world" setting

OBJECTIVE

Patients with amyotrophic lateral sclerosis (ALS) caused by superoxide dismutase 1 (SOD1) gene mutations (SOD1 ALS) treated with tofersen have shown slowing of disease progression, and disease stabilization with recovery of function in some patients. We report our clinical experience with treating patients with SOD1 ALS and the effects of tofersen on outcome measures.

METHODS

This was a single-center observational study of patients with SOD1 ALS receiving treatment with tofersen. The effects of tofersen treatment on neurofilament levels, muscle strength, and clinical outcome measures were assessed. Several patients had outpatient neuromuscular rehabilitation in addition to tofersen treatment and we report changes in functional outcomes.

RESULTS

Seven SOD1 ALS patients received treatment at our institution. All patients showed robust and sustained declines in serum NfL and CSF pNFH (mean change serum NfL: -57.9%; mean change CSF pNFH: -67.6%). There was apparent disease stabilization as assessed by the ALSFRS-R total score, mean change 1.1 (SD = 0.7). There was notable improvement in functional independence measured by the FIM motor score, mean change 5.13 points (SD = 3.85).

INTERPRETATION

This study provides evidence that tofersen treatment in SOD1 ALS can lead to meaningful preservation of function and suggestions of sustained improvement in neurologic function in some patients, and strongly supports the role of neurofilaments as therapeutic biomarkers.

Amyotrophic lateral sclerosis caused by SOD1 variants: from genetic discovery to disease prevention

Pathogenic variants in the superoxide dismutase 1 (SOD1) gene were the first identified genetic cause of amyotrophic lateral sclerosis (ALS), in 1993. This discovery enabled the development of transgenic rodent models for studying the biology of SOD1 ALS. The understanding that SOD1 ALS is driven by a toxic gain-of-function mutation has led to therapeutic strategies that aim to lower concentrations of SOD1 protein, an endeavour that has been complicated by the phenotypic heterogeneity of SOD1 ALS. The successful development of genetically targeted therapies to reduce SOD1 expression, together with a better understanding of pre-symptomatic disease and the discovery of neurofilament light protein as a susceptibility/risk biomarker that predicts phenoconversion, has ushered in a new era of trials that aim to prevent clinically manifest SOD1 ALS. The 30-year journey from gene discovery to gene therapy has not only uncovered the pathophysiology of SOD1 ALS, but has also facilitated the development of biomarkers that should aid therapy development for all forms of ALS.

Genetic testing for monogenic forms of motor neuron disease/amyotrophic lateral sclerosis in unaffected family members

Motor neuron disease (MND), also referred to as amyotrophic lateral sclerosis (ALS), is a monogenic disease in a minority of cases, with autosomal dominant inheritance. Increasing numbers of people with MND are requesting genetic testing, and indeed receiving a genetic diagnosis. Consequently, requests for genetic counselling and predictive testing (i.e. of unaffected family members) are similarly expected to rise, alongside pre-symptomatic clinical trials. Despite this, there is no evidence-based guideline for predictive genetic testing in MND. This paper provides an overview of the genomic basis of MND, focusing specifically on the most common monogenic causes of MND. It then lays out the complexities of MND predictive testing, including the genetic landscape characterised by incomplete penetrance, clinical and genetic heterogeneity, and an oligogenic mechanism of pathogenesis in some cases. Additionally, there is limited research on the psychosocial impact of predictive genetic testing for MND, with studies suggesting potential difficulty in adjusting to the news, in part due to a lack of support and follow-up. This underscores a case for evidence-based, disease-specific guidance for predictive testing in MND.

New developments in the diagnosis and management of motor neuron disease

INTRODUCTION

Motor neuron disease (MND) is a devastating neurodegenerative disease characterized by progressive muscle weakness.

SOURCES OF DATA

PubMed, MEDLINE, and Cochrane databases were searched for articles to March 2024. Searches involved the terms 'motor neuron disease' or 'amyotrophic lateral sclerosis' and 'epidemiology', 'diagnosis', 'clinical', 'genetic', 'management', 'treatment', or 'trial'.

AREAS OF AGREEMENT

Evidence-based management involves riluzole, multidisciplinary care, provision of noninvasive ventilation and gastrostomy, and symptomatic treatments. Tofersen should be offered to treat SOD1-MND.

AREAS OF CONTROVERSY

Edaravone and Relyvrio are approved treatments in the USA, but insufficient evidence was found to support approval in the UK and Europe.

GROWING POINTS

The discovery of neurofilaments as MND biomarkers, growth of platform trials and development of novel therapies provide optimism for more powerful neuroprotective therapies.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further work should focus on the elucidation of environmental causes of MND, gene-environment interactions, and advanced cellular models of disease.

The Answer ALS return of results study: Answering the duty to disclose

Objective: The Return of Answer ALS Results (RoAR) Study was designed to provide a mechanism for participants in Answer ALS, a large, prospectively designed natural history and biorepository study to receive select clinical genetic testing results and study participants' experience with the results disclosure. Methods: Participants consented to receive results of five ALS genes (C9orf72, SOD1, FUS, TARDP, TBK1) and/or 59 medically actionable genes as designated by the American College of Medical Genetics. Patient-reported genetic testing outcomes were measured via a post-disclosure survey. Results: Of 645 eligible Answer ALS enrollees, 143 (22%) enrolled and completed participation in RoAR. Pathogenic variants were identified in 22/143 (15.4%) participants, including 13/143 (9.0%) in ALS genes and 9/143 (6.3%) in ACMG genes. Participant-reported measures of result utility indicated the research result disclosure was as or more successful than published patient-reported outcomes of result disclosure the clinical setting. Conclusions: This study serves as a model of a "disclosure study" to share results from genomic research with participants who were not initially offered the option to receive results, and our findings can inform the design of future, large scale genomic projects to empower research participants to access their genetic information.

Health care resource utilization and costs across stages of amyotrophic lateral sclerosis in the United States

BACKGROUND

People living with ALS (plwALS) experience motor control loss, speech/swallowing difficulties, respiratory insufficiency, and early death. Advancing disease stage is typically associated with a greater burden on the health care system, and delays in diagnosis can result in substantial health care resource utilization (HCRU).

OBJECTIVE

To estimate HCRU and cost burden of plwALS across disease stages from a US payer perspective we assessed HCRU and costs in early-, mid-, and late-stage ALS.

METHODS

Using insurance claims data from the IBM MarketScan Databases between January 2013 and December 2019, we identified plwALS as having at least 2 claims at least 27 days apart with an ALS International Classification of Diseases, Ninth or Tenth Revision diagnosis code (335.20/G12.21) or at least 1 ALS diagnosis code and prescription filled for riluzole/edaravone. Eligible plwALS were aged at least 18 years and had at least 12 months of enrollment data before and at least 6 months after the index date (date diagnosis criteria met). plwALS were grouped into disease stages using an ALS severity-based staging algorithm developed using ALS symptom and staging survey data from 142 neurologists reporting on 880 plwALS. The starting date of each severity stage was defined as the first date of an ALS symptom within the early-, mid-, and late-stage categories, respectively. The ending date for a severity stage was defined as the day before the first date of an ALS symptom from a more severe category. plwALS could transition to more severe stages, with reverse transition of severity excluded. Mixed regression modeling was used to assess differences in HCRU and costs per person-year between severity stages, adjusted for age and sex.

RESULTS

2,273 plwALS were included in the total ALS study sample, with 1,215 early-stage, 1,511 midstage, and 1,186 late-stage plwALS. 90% of early-stage plwALS had ALS symptoms before diagnosis, and 27% of late-stage plwALS had a late-stage symptom before diagnosis. In the evaluation period, later-stage ALS groups had more overall hospital admissions (early = 0.15, middle = 0.23, and late = 0.74; P < 0.01), outpatient visits/service (early = 26.81, middle = 32.78, and late = 48.54; P < 0.01), emergency department visits (early = 0.46, middle = 0.69, and late = 1.03; P < 0.01), and total prescription count (early = 9.23, middle = 11.37, and late = 12.72; P < 0.01) over 12 months. Annualized costs increased as ALS progressed (early = $31,411, middle = $51,481, and late = $121,903; P < 0.01), which was primarily driven by higher frequency of and cost per hospital admission.

CONCLUSIONS

HCRU and costs increased with ALS progression, with diagnosis frequently occurring even after experiencing late-stage symptoms. These findings highlight the potential value of delaying progression into a more resource-intensive stage by diagnosing and adequately treating plwALS earlier in the disease course.

The genetics of amyotrophic lateral sclerosis

PURPOSE OF REVIEW

Amyotrophic lateral sclerosis (ALS) has a strong genetic basis, but the genetic landscape of ALS appears to be complex. The purpose of this article is to review recent developments in the genetics of ALS.

RECENT FINDINGS

Large-scale genetic studies have uncovered more than 40 genes contributing to ALS susceptibility. Both rare variants with variable effect size and more common variants with small effect size have been identified. The most common ALS genes are C9orf72 , SOD1 , TARDBP and FUS . Some of the causative genes of ALS are shared with frontotemporal dementia, confirming the molecular link between both diseases. Access to diagnostic gene testing for ALS has to improve, as effective gene silencing therapies for some genetic subtypes of ALS are emerging, but there is no consensus about which genes to test for.

SUMMARY

Our knowledge about the genetic basis of ALS has improved and the first effective gene silencing therapies for specific genetic subtypes of ALS are underway. These therapeutic advances underline the need for better access to gene testing for people with ALS. Further research is needed to further map the genetic heterogeneity of ALS and to establish the best strategy for gene testing in a clinical setting.

Tofersen for SOD1 ALS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative condition affecting the motor system. The heterogenous nature of ALS complicates trial design. Genetic forms of ALS present an opportunity to intervene in a less heterogeneous population. ALS associated with gain of function mutations in SOD1 make 'knock-down' strategies an attractive therapeutic approach. Tofersen, an antisense oligonucleotide that reduces expression of SOD1 via RNAase mediated degradation of SOD1 mRNA, has shown robust effects on ALS biomarkers. While a Phase III trial of tofersen failed to meet its primary end point, open label extension data suggests that tofersen slows progression of SOD1 ALS.

Diagnostic and clinical utility of comprehensive multigene panel testing for patients with neuropathy

BACKGROUND AND AIMS

Prior to next-generation sequencing (NGS), the evaluation of a patient with neuropathy typically consisted of screening for acquired causes, followed by clinical genetic testing of PMP22, MFN2, GJB1, and MPZ in patients with a positive family history and symptom onset prior to age 50. In this study, we examined the clinical utility of NGS in a large cohort of patients analyzed in a commercial laboratory.

METHODS

A cohort of 6849 adult patients underwent clinician-ordered peripheral neuropathy multigene panel testing ranging from 66 to 111 genes that included NGS and intragenic deletion/duplication analysis.

RESULTS

A molecular diagnosis was identified for 8.4% of the cohort (n = 573/6849). Variants in PMP22, MFN2, GJB1, MPZ, and TTR accounted for 73.8% of molecular diagnoses. Results had potential clinical actionability for 398 (69.5%) patients. Our results suggest that 225/573 (39.3%) of molecular diagnoses and 113/398 (28.4%) of clinical interventions would have been missed if the testing approach had been restricted to older guidelines.

INTERPRETATION

Our results highlight the need for expanded genetic testing guidelines that account for the increased number of genes associated with hereditary neuropathy, address the overlap of acquired and hereditary neuropathy, and provide broader access to genetic diagnosis for patients.

ALS Identified: two-year findings from a sponsored ALS genetic testing program

OBJECTIVE

To report initial results from the Amyotrophic Lateral Sclerosis (ALS) Identified genetic testing (GT) program on characteristics of individuals tested and frequency of reported disease-causing variants.

METHODS

ALS Identified used the Invitae Amyotrophic Lateral Sclerosis panel (Invitae, San Francisco, CA, USA) to assay 22 ALS-associated genes. Sponsored by Biogen (Cambridge, MA, USA), the program was launched in June 2021 and was available at no charge to individuals ≥18 years in the United States and Puerto Rico with an ALS diagnosis or a known family history of ALS. Deidentified data were available to Biogen.

RESULTS

As of 26 October 2023, 998 healthcare professionals ordered the panel at 681 unique care sites. Of 8054 individuals examined, 7483 (92.9%) were reported to have a clinical diagnosis of ALS, while 571 (7.1%) were asymptomatic relatives. Of the individuals with a clinical ALS diagnosis, 57.7% were male (n = 4319) and 42.3% female (n = 3164). Mean (SD) age at diagnosis is 62 (13) years. Out of the 7483 clinically diagnosed individuals, 1810 (24.2%) showed genetic variations in ALS-associated genes. Among these, 865 individuals (47.8%) carried pathogenic variants, and 44 (2.4%) had likely pathogenic variants, totaling 12.1% of the clinically diagnosed population.

INTERPRETATION

Since 2021 there has been robust uptake and sustained use of the ALS Identified program, one of the largest samples of people with ALS to date across the United States, demonstrating the interest and need for genetic ALS testing.

Survey of service needs to embed genome sequencing for motor neuron disease in neurology in the English National Health Service

All people with motor neuron disease (pwMND) in England are eligible for genome sequencing (GS), with panel-based testing. With the advent of genetically targeted MND treatments, and increasing demand for GS, it is important that clinicians have the knowledge and skills to support pwMND in making informed decisions around GS. We undertook an online survey of clinical genomic knowledge and genetic counselling skills in English clinicians who see pwMND. There were 245 respondents to the survey (160 neurology clinicians and 85 genetic clinicians). Neurology clinicians reported multiple, overlapping barriers to offering pwMND GS. Lack of time to discuss GS in clinic and lack of training in genetics were reported. Neurology clinicians scored significantly less well on self-rated genomic knowledge and genetic counselling skills than genetic clinicians. The majority of neurology clinicians reported that they do not have adequate educational or patient information resources to support GS discussions. We identify low levels of genomic knowledge and skills in the neurology workforce. This may impede access to GS and precision medicine for pwMND.

European Academy of Neurology (EAN) guideline on the management of amyotrophic lateral sclerosis in collaboration with European Reference Network for Neuromuscular Diseases (ERN EURO-NMD)

BACKGROUND

This update of the guideline on the management of amyotrophic lateral sclerosis (ALS) was commissioned by the European Academy of Neurology (EAN) and prepared in collaboration with the European Reference Network for Neuromuscular Diseases (ERN EURO-NMD) and the support of the European Network for the Cure ALS (ENCALS) and the European Organization for Professionals and Patients with ALS (EUpALS).

METHODS

Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology was used to assess the effectiveness of interventions for ALS. Two systematic reviewers from Cochrane Response supported the guideline panel. The working group identified a total of 26 research questions, performed systematic reviews, assessed the quality of the available evidence, and made specific recommendations. Expert consensus statements were provided where insufficient evidence was available.

RESULTS

A guideline mapping effort revealed only one other ALS guideline that used GRADE methodology (a National Institute for Health and Care Excellence [NICE] guideline). The available evidence was scarce for many research questions. Of the 26 research questions evaluated, the NICE recommendations could be adapted for 8 questions. Other recommendations required updates of existing systematic reviews or de novo reviews. Recommendations were made on currently available disease-modifying treatments, multidisciplinary care, nutritional and respiratory support, communication aids, psychological support, treatments for common ALS symptoms (e.g., muscle cramps, spasticity, pseudobulbar affect, thick mucus, sialorrhea, pain), and end-of-life management.

CONCLUSIONS

This update of the guideline using GRADE methodology provides a framework for the management of ALS. The treatment landscape is changing rapidly, and further updates will be prepared when additional evidence becomes available.

Amyotrophic lateral sclerosis; clinical features, differential diagnosis and pathology

Amyotrophic lateral sclerosis (ALS) is a late-onset syndrome characterized by the progressive degeneration of both upper motor neurons (UMN) and lower motor neurons (LMN). ALS forms a clinical continuum with frontotemporal dementia (FTD), in which there are progressive language deficits or behavioral changes. The genetics and pathology underlying both ALS and FTD overlap as well, with cytoplasmatic misvocalization of TDP-43 as the hallmark. ALS is diagnosed by exclusion. Over the years several diagnostic criteria have been proposed, which in essence all require a history of slowly progressive motor symptoms, with UMN and LMN signs on neurological examination, clear spread of symptoms through the body, the exclusion of other disorder that cause similar symptoms and an EMG that it is compatible with LMN loss. ALS is heterogeneous disorder that may present in multitude ways, which makes the diagnosis challenging. Therefore, a systematic approach in the diagnostic process is required in line with the most common presentations. Subsequently, assessing whether there are cognitive and/or behavioral changes within the spectrum of FTD and lastly determining the cause is genetic. This chapter, an outline on how to navigate this 3 step process.

Distribution of the C9orf72 hexanucleotide repeat expansion in healthy subjects: a multicenter study promoted by the Italian IRCCS network of neuroscience and neurorehabilitation

Introduction

High repeat expansion (HRE) alleles in C9orf72 have been linked to both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD); ranges for intermediate allelic expansions have not been defined yet, and clinical interpretation of molecular data lacks a defined genotype-phenotype association. In this study, we provide results from a large multicenter epidemiological study reporting the distribution of C9orf72 repeats in healthy elderly from the Italian population.

Methods

A total of 967 samples were collected from neurologically evaluated healthy individuals over 70 years of age in the 13 institutes participating in the RIN (IRCCS Network of Neuroscience and Neurorehabilitation) based in Italy. All samples were genotyped using the AmplideXPCR/CE C9orf72 Kit (Asuragen, Inc.), using standardized protocols that have been validated through blind proficiency testing.

Results

All samples carried hexanucleotide G4C2 expansion alleles in the normal range. All samples were characterized by alleles with less than 25 repeats. In particular, 93.7% of samples showed a number of repeats ≤10, 99.9% ≤20 repeats, and 100% ≤25 repeats.

Conclusion

This study describes the distribution of hexanucleotide G4C2 expansion alleles in an Italian healthy population, providing a definition of alleles associated with the neurological healthy phenotype. Moreover, this study provides an effective model of federation between institutes, highlighting the importance of sharing genomic data and standardizing analysis techniques, promoting translational research. Data derived from the study may improve genetic counseling and future studies on ALS/FTD.