Pre-symptomatic diagnosis in ALS

The various forms of hereditary motor neuron disorders and their historical descriptions

Motor neuron disorders comprise a clinically and pathologically heterogeneous group of neurologic diseases characterized by progressive degeneration of motor neurons (including both sporadic and hereditary diseases), affecting the upper motor neurons, lower motor neurons, or both. Hereditary motor neuron disorders themselves represent a vast and heterogeneous group, with numerous clinical and genetic overlaps that can be a source of error. This narrative review aims at providing an overview of the main types of inherited motor neuron disorders by recounting the stages in their historical descriptions. For practical purposes, this review of the literature sets out their various clinical characteristics and updates the list of all the genes involved in the various forms of inherited motor neuron disorders, including spinal muscular atrophy, familial amyotrophic lateral sclerosis, hereditary spastic paraplegia, distal hereditary motor neuropathies/neuronopathies, Kennedy's disease, riboflavin transporter deficiencies, VCPopathy and the neurogenic scapuloperoneal syndrome.

Studies of Genetic and Proteomic Risk Factors of Amyotrophic Lateral Sclerosis Inspire Biomarker Development and Gene Therapy

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease affecting the upper and lower motor neurons, leading to muscle weakness, motor impairments, disabilities and death. Approximately 5-10% of ALS cases are associated with positive family history (familial ALS or fALS), whilst the remainder are sporadic (sporadic ALS, sALS). At least 50 genes have been identified as causative or risk factors for ALS. Established pathogenic variants include superoxide dismutase type 1 (SOD1), chromosome 9 open reading frame 72 (c9orf72), TAR DNA Binding Protein (TARDBP), and Fused In Sarcoma (FUS); additional ALS-related genes including Charged Multivesicular Body Protein 2B (CHMP2B), Senataxin (SETX), Sequestosome 1 (SQSTM1), TANK Binding Kinase 1 (TBK1) and NIMA Related Kinase 1 (NEK1), have been identified. Mutations in these genes could impair different mechanisms, including vesicle transport, autophagy, and cytoskeletal or mitochondrial functions. So far, there is no effective therapy against ALS. Thus, early diagnosis and disease risk predictions remain one of the best options against ALS symptomologies. Proteomic biomarkers, microRNAs, and extracellular vehicles (EVs) serve as promising tools for disease diagnosis or progression assessment. These markers are relatively easy to obtain from blood or cerebrospinal fluids and can be used to identify potential genetic causative and risk factors even in the preclinical stage before symptoms appear. In addition, antisense oligonucleotides and RNA gene therapies have successfully been employed against other diseases, such as childhood-onset spinal muscular atrophy (SMA), which could also give hope to ALS patients. Therefore, an effective gene and biomarker panel should be generated for potentially "at risk" individuals to provide timely interventions and better treatment outcomes for ALS patients as soon as possible.

Quality appraisal of clinical practice guidelines for motor neuron diseases or related disorders using the AGREE II instrument

Objectives

This study aimed to systematically assess the quality of CPGs for motor neuron diseases (MNDs) or related disorders and identify the gaps that limit evidence-based practice.

Methods

Four scientific databases and six guideline repositories were searched for eligible CPGs. Three researchers assessed the eligible CPGs using the Appraisal of Guidelines Research and Evaluation II instrument. The distribution of the level of evidence and strength of recommendation of these CPGs were determined. The univariate regression analysis was used to explore the characteristic factors affecting the quality of CPGs.

Results

Fifteen CPGs met the eligibility criteria: 10 were for MND and 5 were for spinal muscular atrophy. The mean overall rating score was 44.5%, and only 3 of 15 CPGs were of high quality. The domains that achieved low mean scores were applicability (24.4%), rigor of development (39.9%), and stakeholder involvement (40.3%). Most recommendations were based on low-quality evidence and had a weak strength. The CPGs that were updated, meant for adults, and evidence based, and used a CPG quality tool and a grading system were associated with higher scores in certain specific domains and overall rating.

Conclusion

The overall quality of CPGs for MNDs or related disorders was poor and recommendations were largely based on low-quality evidence. Many areas still need improvement to develop high-quality CPGs, and the use of CPG quality tools should be emphasized. A great deal of research on MNDs or related disorders is still needed to fill the large evidence gap.

Amyotrophic Lateral Sclerosis and Serum Lipid Level Association: A Systematic Review and Meta-Analytic Study

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with unknown etiology. Many metabolic alterations occur during ALS progress and can be used as a method of pre-diagnostic and early diagnosis. Dyslipidemia is one of the physiological changes observed in numerous ALS patients. The aim of this study is to analyze the possible relationship between the rate of disease progression (functional rating scale (ALS-FRS)) and the plasma lipid levels at the early stage of ALS. A systematic review was carried out in July 2022. The search equation was "Triglycerides AND amyotrophic lateral sclerosis" and its variants. Four meta-analyses were performed. Four studies were included in the meta-analysis. No significant differences were observed between the lipid levels (total cholesterol, triglycerides, HDL cholesterol, and LDL cholesterol) and the ALS-FRS score at the onset of the disease. Although the number of studies included in this research was low, the results of this meta-analytic study suggest that there is no clear relationship between the symptoms observed in ALS patients and the plasma lipid levels. An increase in research, as well as an expansion of the geographical area, would be of interest.

Neuroprotective Effect of Sonic Hedgehog Mediated PI3K/AKT Pathway in Amyotrophic Lateral Sclerosis Model Mice

The Sonic Hedgehog (SHH) signaling pathway is related to the progression of various tumors and nervous system diseases. Still, its specific role in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), remains studied. This research investigates the role of SHH and PI3K/AKT signaling pathway proteins on ALS development in a SOD1-G93A transgenic mouse model. After injection of SHH and PI3K/AKT signaling pathway inhibitors or agonists in hSOD1-G93A (9 weeks of age) transgenic mice, we studied skeletal muscle pathology using immunohistochemical staining and Western blot methods. In addition, recorded data on rotation time, weight, and survival were analyzed for these mice. Our study showed that the expression of SHH, Gli-1 and p-AKT in ALS mice decreased with the progression of the disease. The expression of p-AKT changed together with Gli-1 while injecting PI3K/AKT signaling pathway inhibitor or agonist; SHH and Gli-1 protein expression remained unchanged; p-AKT protein expression significantly decreased while injecting PI3K/AKT signaling pathway inhibitor. These results indicate that SHH has a regulatory effect on PI3K/AKT signaling pathway. In behavioral experiments, we found that the survival time of hSOD1-G93A mice was prolonged by injection of SHH agonist while shortened by injection of SHH inhibitor. In conclusion, we confirmed that the SHH pathway played a neuroprotective role in ALS by mediating PI3K/AKT signaling pathway.

Patient and Relative Experiences and Decision-making About Genetic Testing and Counseling for Familial ALS and FTD: A Systematic Scoping Review

Genetic testing and counseling is an emerging part of care for patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) and their families. This scoping review aimed to map patients' and relatives' experiences of genetic testing and counseling for familial ALS and FTD and the factors influencing their decision to proceed with testing or counseling. Informed by the Joanna Briggs Institute methodology, 5 databases were systematically searched. Thirty studies from 39 references were included. A descriptive numerical summary analysis and narrative synthesis was conducted. Mostly positive diagnostic testing experiences were reported, but issues arose due to progressive disease and discordant results. Predictive testing impacted at-risk relatives, regardless of the result received, and psychosocial sequelae ranged from relief to guilt, worry or contemplating suicide. Four reproductive testing experiences were reported. Personal, familial and practical factors, and the lived experience of disease, informed decision-making. Greater uncertainty and complexity may be faced in familial ALS/FTD than in other late-onset neurodegenerative diseases due to clinical and genetic heterogeneity, and testing limitations. Genetic counseling models of care should consider this difference to ensure that individuals with, or at risk of, ALS/FTD are effectively managed. Implications for research and practice are discussed.

Current Concepts on Genetic Aspects of Mitochondrial Dysfunction in Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS), neurodegenerative motor neuron disorder is characterized as multisystem disease with important contribution of genetic factors. The etiopahogenesis of ALS is not fully elucidate, but the dominant theory at present relates to RNA processing, as well as protein aggregation and miss-folding, oxidative stress, glutamate excitotoxicity, inflammation and epigenetic dysregulation. Additionally, as mitochondria plays a leading role in cellular homeostasis maintenance, a rising amount of evidence indicates mitochondrial dysfunction as a substantial contributor to disease onset and progression. The aim of this review is to summarize most relevant findings that link genetic factors in ALS pathogenesis with different mechanisms with mitochondrial involvement (respiratory chain, OXPHOS control, calcium buffering, axonal transport, inflammation, mitophagy, etc.). We highlight the importance of a widening perspective for better understanding overlapping pathophysiological pathways in ALS and neurodegeneration in general. Finally, current and potentially novel therapies, especially gene specific therapies, targeting mitochondrial dysfunction are discussed briefly.