End of life decision making when home mechanical ventilation is used to sustain breathing in Motor Neurone Disease: patient and family perspectives.

BACKGROUND: Motor Neurone Disease (MND) leads to muscle weakening, affecting movement, speech, and breathing. Home mechanical ventilation, particularly non-invasive ventilation (NIV), is used to alleviate symptoms and support breathing in people living with MND. While home mechanical ventilation can alleviate symptoms and improve survival, it does not slow the progression of MND. This study addresses gaps in understanding end-of-life decision-making in those dependent on home mechanical ventilation, considering the perspectives of patients, family members, and bereaved families. METHODS: A UK-wide qualitative study using flexible interviews to explore the experiences of people living with MND (n = 16), their family members (n = 10), and bereaved family members (n = 36) about the use of home mechanical ventilation at the end of life. RESULTS: Some participants expressed a reluctance to discuss end-of-life decisions, often framed as a desire to "live for the day" due to the considerable uncertainty faced by those with MND. Participants who avoided end-of-life discussions often engaged in 'selective decision-making' related to personal planning, involving practical and emotional preparations. Many faced challenges in hypothesising about future decisions given the unpredictability of the disease, opting to make 'timely decisions' as and when needed. For those who became dependent on ventilation and did not want to discuss end of life, decisions were often 'defaulted' to others, especially once capacity was lost. 'Proactive decisions', including advance care planning and withdrawal of treatment, were found to empower some patients, providing a sense of control over the timing of their death. A significant proportion lacked a clear understanding of the dying process and available options. CONCLUSIONS: The study highlights the complexity and evolution of decision-making, often influenced by the dynamic and uncertain nature of MND. The study emphasises the need for a nuanced understanding of decision-making in the context of MND.

Antisense Oligonucleotides (ASOs) in Motor Neuron Diseases: A Road to Cure in Light and Shade.

Antisense oligonucleotides (ASOs) are short oligodeoxynucleotides designed to bind to specific regions of target mRNA. ASOs can modulate pre-mRNA splicing, increase levels of functional proteins, and decrease levels of toxic proteins. ASOs are being developed for the treatment of motor neuron diseases (MNDs), including spinal muscular atrophy (SMA), amyotrophic lateral sclerosis (ALS) and spinal and bulbar muscular atrophy (SBMA). The biggest success has been the ASO known as nusinersen, the first effective therapy for SMA, able to improve symptoms and slow disease progression. Another success is tofersen, an ASO designed to treat ALS patients with SOD1 gene mutations. Both ASOs have been approved by the FDA and EMA. On the other hand, ASO treatment in ALS patients with the C9orf72 gene mutation did not show any improvement in disease progression. The aim of this review is to provide an up-to-date overview of ASO research in MNDs, from preclinical studies to clinical trials and, where available, regulatory approval. We highlight the successes and failures, underline the strengths and limitations of the current ASO research, and suggest possible approaches that could lead to more effective treatments.

An introduction to neuropalliative care: A growing need.

Palliative care (PC) defined as 'an approach improving the quality of life of patients and their families facing problems associated with life-limiting illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain and other problems, physical, psychosocial and spiritual' aims to enhance the improve the remaining time that patients have, emphasising choice for patients and families.1 Patients with neurological disease such as Parkinson's (PD) and motor neurone disease (MND) benefit from PC earlier in disease with increasing emphasis over time. Understanding and communicating uncertain trajectories, honest prognostic communication when patients are ready and careful symptom control has been shown to enhance quality of life in patients and caregivers, giving greater autonomy to these patients when supported in decision-making by a palliative approach. Although obstacles to palliative care are frequent, there are strategies which can help overcome them.

Clinical prognostic factors predicting survival of motor neuron disease patients with gastrostomy: A retrospective analysis.

INTRODUCTION/AIMS: Enteral feeding via gastrostomy is a key intervention to prevent significant weight loss in Motor Neuron Disease (MND). The aim of this study was to explore demographic, clinical, and nutritional factors associated with survival time in MND patients with gastrostomy. METHODS: The retrospective study analyzed 94 MND patients (n = 58 bulbar-onset and n = 36 limb-onset) who underwent gastrostomy between 2015 and 2021. The primary outcome was the survival time from gastrostomy insertion to death. Independent variables of interest explored were: age at gastrostomy insertion, disease onset type, known genetic cause, use of riluzole, non-invasive ventilation (NIV) use, forced vital capacity prior to gastrostomy, weight loss from diagnosis to gastrostomy insertion, and body mass index (BMI) at the time of gastrostomy insertion. RESULTS: The median survival time from gastrostomy to death was 357 days (± 29.3, 95%CI: 299.5, 414.5). Kaplan-Meier method and log-rank test revealed patients with lower body mass index <18.5 kg/m2 at the time of gastrostomy insertion (p = .023) had shorter survival. Cox proportional hazards model with multivariable adjustment revealed that older age (p = .008), and greater weight loss from diagnosis to gastrostomy (p = .003) were associated with shorter survival time post gastrostomy. Limb onset (p = .023), NIV use not being required (p = .008) and daily NIV use when required and tolerated (p = .033) were associated with longer survival. DISCUSSION: Preventing or minimizing weight loss from MND diagnosis and encouraging NIV use when clinically indicated are modifiable factors that may prolong the survival of MND patients with gastrostomy.

A prospective study for using cognitive decline as a predictor for survival and use of feeding/respiratory support for patients with motor neuron disease in Norway.

BACKGROUND: There is a need for knowledge regarding the medical management of motor neuron disease/amyotrophic lateral sclerosis (MND/ALS) with and without cognitive decline. It has scarcely been studied whether cognitive decline will influence the course of disease or interfere with the use of life-prolonging aids for respiration and nutrition. Cognitive decline may impact the length of illness. METHODS: Patients were prospectively recruited from an ALS outpatient clinic at Haukeland University Hospital. Participants underwent the standardized cognitive test Edinburgh Cognitive and Behavioral ALS Screen Norwegian version (ECAS-N), clinical examination, and were functionally assessed by the ALS Functioning Rating Scale-revised version (ALS-FRS-R). The time and indication for installation of a feeding tube [percutaneous endoscopic gastrostomy (PEG)] and/or respiratory aid [bilevel positive airway pressure device (BiPAP)] or invasive respirator were retrieved from the medical records. Kaplan-Meier tests were used to study the risk of death and the probability for implementing PEG and/or BiPAP in relation to time from diagnosis. The individual assessment was used for analyzing the establishment of aids in relation to point of death. RESULTS: A total of 40 patients were evaluated for the study, 31 of whom were finally included. None of the included patients did not use an invasive respirator. The patients were divided into two subgroups (normal cognition or cognitive decline, cut-off 92 points) according to their performance in the ECAS-N. The course of the disease, shown as a risk of death, was higher among the ALS/MND patients with cognitive decline compared to those with cognitive intact function throughout the study period. The cognitive status did not influence the fitting of aids. Use of aids did not influence the survival in subgroups significantly. CONCLUSIONS: The study demonstrated shorter survival for the patients with ALS/MND with cognitive decline compared to those without cognitive decline. The practice and implementation of both BiPAP and PEG did not differ among the ALS/MND patients with and without cognitive decline in Norway.

Novel approaches to motoneuron disease/ALS treatment using non-invasive brain and spinal stimulation: IFCN handbook chapter.

Non-invasive brain stimulation techniques have been exploited in motor neuron disease (MND) with multifold objectives: to support the diagnosis, to get insights in the pathophysiology of these disorders and, more recently, to slow down disease progression. In this review, we consider how neuromodulation can now be employed to treat MND, with specific attention to amyotrophic lateral sclerosis (ALS), the most common form with upper motoneuron (UMN) involvement, taking into account electrophysiological abnormalities revealed by human and animal studies that can be targeted by neuromodulation techniques. This review article encompasses repetitive transcranial magnetic stimulation methods (including low-frequency, high-frequency, and pattern stimulation paradigms), transcranial direct current stimulation as well as experimental findings with the newer approach of trans-spinal direct current stimulation. We also survey and discuss the trials that have been performed, and future perspectives.

Factors associated with grief in informal carers of people living with Motor Neuron Disease: A mixed methods systematic review.

The purpose of this mixed methods systematic review was to identify factors associated with anticipatory grief, post-death grief, and prolonged grief in informal carers of people living with Motor Neuron Disease (MND) to inform future research and practice. Six electronic databases were searched and two quantitative and eight qualitative studies were identified. Five overarching themes were generated through thematic synthesis. The findings suggest that there are factors that may affect different grieving processes. It might be particularly important to target some factors prior and after the death of the person living with MND such as the knowledge about the progression of the disease, changes in relationships, anxiety and depressive symptoms of carers, and planning for death of the care recipient. Factors that may affect all three grieving processes were also identified such as negative experiences of caregiving, experiences of losses, end of life and psychological support, and emotional avoidance coping.

Factors impacting trial participation in people with motor neuron disease.

Motor neuron disease (MND) is a rapidly progressive neurodegenerative disorder with limited treatment options. Historically, neurological trials have been plagued by suboptimal recruitment and high rates of attrition. The Motor Neuron Disease-Systematic Multi-Arm Randomised Adaptive Trial (MND-SMART) seeks to identify effective disease modifying drugs. This study investigates person-specific factors affecting recruitment and retention. Improved understanding of these factors may improve trial protocol design, optimise recruitment and retention. Participants with MND completed questionnaires and this was supplemented with clinical data. 12 months after completing the questionnaires we used MND-SMART recruitment data to establish if members of our cohort engaged with the trial. 120 people with MND completed questionnaires for this study. Mean age at participation was 66 (SD = 9), 14% (n = 17) were categorised as long survivors, with 68% (n = 81) of participants male and 60% (n = 73) had the ALS sub-type. Of the 120 study participants, 50% (n = 60) were randomised into MND-SMART and 78% (n = 94) expressed interest an in participating. After the 1-year follow-up period 65% (n = 39) of the 60 randomised participants remained in MND-SMART. Older age was significantly associated with reduced likelihood of participation (OR = 0.92, 95% CI = 0.88-0.96, p = 0.000488). The findings show that people with MND are highly motivated to engage in research, but older individuals remain significantly less likely to participate. We recommend the inclusion of studies to explore characteristics of prospective and current participants alongside trials.

Amyotrophic Lateral Sclerosis and Other Motor Neuron Diseases.

OBJECTIVE: This article reviews the clinical spectrum of amyotrophic lateral sclerosis (ALS), its variant presentations, and the approach to diagnosis and management. This review includes a detailed discussion of current and emerging disease-modifying therapies and the management of respiratory and bulbar manifestations of disease. An updated review of ALS genetics and pathophysiology is also provided. This article also touches on several other important motor neuron diseases. LATEST DEVELOPMENTS: A new set of simplified diagnostic criteria may help identify patients at earlier stages of the disease. A coformulation of sodium phenylbutyrate and tauroursodeoxycholic acid has been shown to have a significant benefit on disease progression and survival, leading to approval by regulatory authorities in the United States and Canada. An oral formulation of edaravone and an antisense oligonucleotide to a SOD1 gene variation (tofersen) have also recently been approved by the US Food and Drug Administration (FDA). Phase 3 trials of intrathecal mesenchymal stem cells failed to meet primary end points for efficacy. Updated American Academy of Neurology quality measures for the care of patients with ALS were published in 2023. ESSENTIAL POINTS: There has been continued progress in ALS genetics, diagnosis, and disease-modifying therapies. However, we still lack a definitive biomarker or a treatment that can halt the progression or reverse the course of disease. The evolving understanding of the genetic and pathophysiologic underpinnings of disease offers promise for more effective and clinically meaningful treatments in the future.

TDP-43 as a therapeutic target in neurodegenerative diseases: Focusing on motor neuron disease and frontotemporal dementia.

A common feature of adult-onset neurodegenerative diseases is the presence of characteristic pathological accumulations of specific proteins. These pathological protein depositions can vary in their protein composition, cell-type distribution, and intracellular (or extracellular) location. For example, abnormal cytoplasmic protein deposits which consist of the TDP-43 protein are found within motor neurons in patients with amyotrophic lateral sclerosis (ALS, a common form of motor neuron disease) and frontotemporal dementia (FTD). The presence of these insoluble intracellular TDP-43 inclusions suggests that restoring TDP-43 homeostasis represents a potential therapeutical strategy, which has been demonstrated in alleviating neurodegenerative symptoms in cell and animal models of ALS/FTD. We have reviewed the mechanisms that lead to disrupted TDP-43 homeostasis and discussed how small molecule-based therapies could be applied in modulating these mechanisms. This review covers recent advancements and challenges in small molecule-based therapies that could be used to clear pathological forms of TDP-43 through various protein homeostasis mechanisms and advance the way towards finding effective therapeutical drug discoveries for neurodegenerative diseases characterized by TDP-43 proteinopathies, especially ALS and FTD. We also consider the wider insight of these therapeutic strategies for other neurodegenerative diseases.

Novel therapeutic approaches for motor neuron disease.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that leads to the neurodegeneration and death of upper and lower motor neurons (MNs). Although MNs are the main cells involved in the process of neurodegeneration, a growing body of evidence points toward other cell types as concurrent to disease initiation and propagation. Given the current absence of effective therapies, the quest for other therapeutic targets remains open and still challenges the scientific community. Both neuronal and extra-neuronal mechanisms of cellular stress and damage have been studied and have posed the basis for the development of novel therapies that have been investigated on both animal models and humans. In this chapter, a thorough review of the main mechanisms of cellular damage and the respective therapeutic attempts targeting them is reported. The main areas covered include neuroinflammation, protein aggregation, RNA metabolism, and oxidative stress.

Motor neurone disease: A point-prevalence study of patient reported symptom prevalence, severity and palliative care needs.

BACKGROUND: Motor neurone disease is a rare but debilitating illness with incomplete evidence regarding patients' symptom burden. Palliative care and generalist clinicians are often in-experienced in caring for these patients and assessing their needs. AIM: To identify the symptom prevalence and severity experienced by patients with motor neurone disease. Secondary objectives were to examine differences in symptom burden and clusters according to phenotype, functional status, palliative care provision and those in their last months of life. DESIGN: A point prevalence study assessing patient-reported symptoms using a modified IPOS-Neuro assessment tool, incorporating 41 symptom items. SETTING/PARTICIPANTS: Patients with motor neurone disease attending the State-wide Progressive Neurological Disease Service or inpatient unit at Calvary Health Care Bethlehem, Melbourne Australia, from March to December 2021. RESULTS: A total of 102 patients participated, the majority diagnosed with lumber-onset (30.4%), bulbar-onset (28.4%) and cervical-onset (25.5%) phenotypes. Patients experienced a median of 17 symptoms (range 2-32) with a median of 3 symptoms rated as severe/overwhelming (range 0-13). Motor and functional symptoms predominated, with differences in symptom clusters present according to phenotype. Patients had a higher number of severe/overwhelming symptoms if they were accessing palliative care services (p = 0.005), in their last 6 months of life (p = 0.003) and experiencing moderate or severe functional impairment (p < 0.001). CONCLUSIONS: Patients with motor neurone disease report high symptom burden. A validated motor neurone disease-specific symptom assessment tool is needed to accurately assess patients, including important variations in symptom clusters according to phenotype. Further research must focus on evidence-based treatment guidelines for symptoms experienced commonly and severely.

Altered Metabolism in Motor Neuron Diseases: Mechanism and Potential Therapeutic Target.

Motor Neuron Diseases (MND) are neurological disorders characterized by a loss of varying motor neurons resulting in decreased physical capabilities. Current research is focused on hindering disease progression by determining causes of motor neuron death. Metabolic malfunction has been proposed as a promising topic when targeting motor neuron loss. Alterations in metabolism have also been noted at the neuromuscular junction (NMJ) and skeletal muscle tissue, emphasizing the importance of a cohesive system. Finding metabolism changes consistent throughout both neurons and skeletal muscle tissue could pose as a target for therapeutic intervention. This review will focus on metabolic deficits reported in MNDs and propose potential therapeutic targets for future intervention.

The need to consider 'temporality' in person-centred care of people with motor neurone disease.

AIMS AND OBJECTIVES: The overall aim of this paper is to provide practical insight into the way that professionals caring for a person with motor neurone disease (MND) can recognise, respect and respond to that person's temporality; that is, the person that they have been, that they are now and that they will be in the future. BACKGROUND: MND is an umbrella term for a group of four rare, devastating neurodegenerative terminal diseases of middle/later life. Previously, we have acknowledged the importance of different time periods in the trajectory of MND as an illness, for example, during the diagnosis stage through to end of life and decision-making at that time. Living with MND can cause anxiety at all stages of the disease trajectory especially as it can be difficult for people living with MND to communicate their desires and concerns to professionals and carers. It is important that professionals continue to provide holistic care throughout the illness trajectory and the aim of this paper is to explore past research about caring for someone with MND in relation to the concept of person-centred care. METHOD: The paper is based on the concatenated exploration of the findings of a hermeneutic phenomenological project. Thus, this discursive paper links elements/studies which have been published previously to develop a model of person-centred care for people with MND which recognises and respects their temporality. CONCLUSIONS: We suggest MND has a significant impact on a person's lifeworld. The proposed person-centred care model focuses on understanding (interpreting) a person in a wider temporal frame and beyond the context of their illness. The expected collaborative outcomes are that: a person is acknowledged as more than a 'patient with MND' and that a professional is providing person-centred care based on individuality of the person, through a temporal lens. This requires a collaborative approach between the person, others and professionals. Such person-centred care, focused on individuality, may prevent a person experiencing life in crisis and suffering towards the end of life.

Factors influencing decisions people with motor neuron disease make about gastrostomy placement and ventilation: A qualitative evidence synthesis.

BACKGROUND: People with motor neuron disease (pwMND) are routinely offered gastrostomy feeding tube placement and (non-invasive and invasive) ventilation to manage the functional decline associated with the disease. This study aimed to synthesise the findings from the qualitative literature to understand how individual, clinical team and organisational factors influence pwMND decisions about these interventions. METHODS: The study design was guided by the enhancing transparency in reporting the synthesis of qualitative research (ENTREC) statement. The search of five bibliography databases and an extensive supplementary search strategy identified 27 papers that included qualitative accounts of pwMND, caregivers and healthcare professionals' (HCPs) experiences of making decisions about gastrostomy and ventilation. The findings from each study were included in a thematic synthesis. FINDINGS: Making decisions about interventions is an emotional rather than simply a functional issue for pwMND. The interventions can signal an end to normality, and increasing dependence, where pwMND consider the balance between quality of life and extending survival. Interactions with multiple HCPs and caregivers can influence the process of decision-making and the decisions made. These interactions contribute to the autonomy pwMND are able to exert during decision-making. HCPs can both promote and threaten pwMND perceived agency over decisions through how they approach discussions about these interventions. Though there is uncertainty over the timing of interventions, pwMND who agree to interventions report reaching a tipping point where they accept the need for change. CONCLUSION: Discussion of gastrostomy and ventilation options generate an emotional response in pwMND. Decisions are the consequence of interactions with multiple external agents, including HCPs treading a complex ethical path when trying to improve health outcomes while respecting pwMND right to autonomy. Future decision support interventions that address the emotional response and seek to support autonomy have the potential to enable pwMND to make informed and timely decisions about gastrostomy placement and ventilation. PATIENT OR PUBLIC CONTRIBUTION: The lead author collaborated with several patient and participant involvement (PPI) groups with regards to the conceptualisation and design of this project. Decisions that have been influenced by discussions with multiple PPI panels include widening the scope of decisions about ventilation in addition to gastrostomy placement and the perceptions of all stakeholders involved (i.e., pwMND, caregivers and HCPs).

Characteristic and management motor neuron disease in the largest tertiary hospital in the Philippines: A one-year period cross sectional analytic study.

BACKGROUND: Motor neuron disease (MND) is largely understudied in many underdeveloped and developing countries, including the Philippines. The practice and management of MND is generally insufficient, and thus, the quality of life of these patients are consequently compromised. OBJECTIVES: The aim of this study is to determine the clinical profile and describe the management of MND patients seen in the largest tertiary hospital in the Philippines for one year. METHODS: This is a cross-sectional study of MND patients diagnosed clinically and via electromyogram-nerve conduction study (EMG NCS) in the Philippine General Hospital (PGH) from January to December 2022. Clinical characteristics, diagnostics and management information were obtained and summarized. RESULTS: The incidence of MND in our neurophysiology unit was 4.3% (28/648), with amyotrophic lateral sclerosis (ALS) being the most common variant (67.9%, n = 19). Male to Female ratio was 1:1, with the median age of onset of 55 (36-72) years old and median onset duration to diagnosis of 1.5 (0.25-8) years. Limb onset was more prevalent (82.14%, n = 23) with upper limbs initially involved (79.1%, n = 18). Split hand syndrome was found in almost half (53.6%) of the patients. The median ALS functional rating score-revised (ALSFRS-R) and medical research council (MRC) scores were 34 (8-47) and 42(16-60) respectively while the median King's clinical stage was 3 (1-4). Only half of the patients were able to undergo magnetic resonance imaging (MRI) and only one had neuromuscular ultrasound. Only one of the 28 patients was able to take riluzole, and only one was on oxygen support. None had gastrostomy and none used non-invasive ventilation. CONCLUSION: This study showed that the management of MND in the Philippines is largely inadequate and further improvement in the health care system in handling rare neurologic cases must be implemented to enhance their quality of life.

[Amyotrophic lateral sclerosis-Motor neuron disease with a wide clinical and genetic spectrum]. / Amyotrophe Lateralsklerose ­ Motoneuronerkrankung mit großem klinischem und genetischem Spektrum.

BACKGROUND: Amyotrophic lateral sclerosis (ALS) is the most frequent motor neuron disease. Besides a timely diagnosis, precise knowledge of the clinical manifestations and differential diagnoses is essential. While most patients develop the disease at an older age, hereditary causes play a more frequent role in the juvenile forms. OBJECTIVE: What is the current state of ALS diagnostics, which new treatment options exist? MATERIAL AND METHOD: Literature search using Pubmed.gov. RESULTS: The main focus is on an individualized symptomatic treatment as no curative treatment approaches exist. However, new insights into the genetic and pathophysiological principles of the different forms of ALS open the way for future disease-modifying treatment options. CONCLUSION: In cases of a clinical suspicion of ALS molecular genetic diagnostics should be considered, particularly in juvenile and young adult patients, to exclude differential diagnoses and to enable patients access to new treatment approaches.

Understanding living with tracheostomy ventilation for motor neuron disease and the implications for quality of life: a qualitative study protocol.

INTRODUCTION: Home mechanical ventilation can be used to manage symptoms of breathlessness and sustain life for people living with motor neuron disease (plwMND). In the UK, less than 1% of plwMND use tracheostomy ventilation (TV). This contrasts with some other countries, where rates are much higher. Due to a lack of evidence about its feasibility, cost-effectiveness or outcomes, TV is not covered in the UK National Institute for Health and Care Excellence guidance. Most plwMND receiving TV in the UK do so as an unplanned crisis intervention, which can lead to a prolonged hospital stay while a complex care package is arranged. There is insufficient literature addressing the burdens and benefits of TV, how it should be initiated and delivered, and how future care choices for plwMND can be supported. The aim of this research is to provide new understandings of the experiences of plwMND using TV, and those of family members and healthcare professionals (HCPs) involved in their care. METHODS AND ANALYSIS: A UK-wide qualitative study with two workstreams: (1) Patient focused case studies (n=6) including plwMND, family members and HCPs to focus on experiences and tasks of daily living from multiple perspectives. (2) Interviews with plwMND (n=10), family members, including bereaved family members (n=10) and HCPs (n=20) on broader experiences and issues relating to use of TV, such as ethical considerations and decision making. ETHICS AND DISSEMINATION: Ethical approval has been granted by the Leicester South Research Ethics Committee (22/EM/0256). All participants will be asked to provide electronic, written and/or audio recorded informed consent. Study findings will be disseminated in peer-reviewed journals and conference presentations and used to develop new resources for teaching and public information.

[Gene Therapies in Motor Neuron Diseases ALS and SMA]. / Gentherapien bei den Motoneuronerkrankungen ALS und SMA.

In the past, the diagnosis of motor neuron diseases such as amyotrophic lateral sclerosis (ALS) and 5q-associated spinal muscular atrophy (SMA) meant powerlessness in the face of seemingly untreatable diseases with severe motor-functional limitations and sometimes fatal courses. Recent advances in an understanding of the genetic causalities of these diseases, combined with success in the development of targeted gene therapy strategies, spell hope for effective, innovative therapeutic approaches, pioneering the ability to treat neurodegenerative diseases. While gene therapies have been approved for SMA since a few years, gene therapy research in ALS is still in clinical trials with encouraging results. This article provides an overview of the genetic background of ALS and SMA known to date and gene therapy approaches to them with a focus on therapy candidates that are in clinical trials or have already gained market approval.