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Introduction/aims: Nusinersen intrathecal administration can be challenging in spinal muscular atrophy (SMA) adults. We aimed to determine if the ultrasound (US)-assistance reduces the number of needle attempts and needle redirections needed for intrathecal drug administration and its impact on the procedure time, the incidence of adverse events (AEs), and patient satisfaction in these patients., Methods: Fifty-eight patients aged 18 years and older scheduled for intrathecal nusinersen injection were enrolled and randomized (1:1 ratio) into Group 1 (nusinersen infusion with US-assisted technique) or Group 2 (nusinersen infusion with landmark-based technique). The number of attempts, number of redirections, periprocedural time, AEs and patient satisfaction were reported. Continuous variables were compared with the Student t-test or Wilcoxon rank sum test. Categorical variables were evaluated with the Chi-square test or Fisher's exact test in case of expected frequencies <5. The p-values <.05 were considered statistically significant., Results: There were no statistical differences in the number of attempts, AEs, or patient satisfaction between the two groups. The number of needle redirections was significantly lower in the ultrasound group versus landmark-based group (p < .05) in both the overall group of patients and in the subgroup with difficult spines. The periprocedural time was about 40 seconds longer in US-group versus landmark-based group (p < .05)., Discussion: In SMA adults, US assistance reduces the number of needle redirections needed for intrathecal drug administration. These results suggest that the US assistance may be advantageous for nusinersen therapy to reduce the therapeutic burden of intrathecal infusion., (© 2024 Wiley Periodicals LLC.)

The nutritional implications of spinal muscular atrophy (SMA) are profound. Disease modifying therapies (DMT) have improved clinical outcomes. This review describes the impact of DMT on nutrition outcomes. A systematic search strategy was applied across seven databases until May 2023. Eligible studies measured nutrition outcomes in individuals with SMA on DMT (nusinersen, risdiplam or onasemnogene abeparvovec [OA]) compared to untreated comparators. Nutrition outcomes included anthropometry, feeding route, swallowing dysfunction, dietary intake, dietetic intervention, nutritional biochemistry, metabolism, gastrointestinal issues and energy expenditure. Articles retrieved were screened in duplicate, data were extracted and appraised systematically. Sixty three articles from 54 studies were included; 41% (n = 22) investigated nusinersen in pediatric participants with SMA type 1. Anthropometry (n = 18), feeding route (n = 39), and swallowing dysfunction (n = 18) were the most commonly reported outcomes. In combined pediatric and adult cohorts, BMI z-score remained stable post nusinersen therapy. The proportion of children with SMA requiring enteral nutrition was stable post nusinersen therapy. Ability to thrive at age 1.5 years was higher in children treated in early infancy with OA compared to historical controls. Significant heterogeneity existed across study population characteristics and outcome measures. Nusinersen may prevent deterioration in some nutrition outcomes; and OA in early infancy may be associated with improved nutrition outcomes. Timing of DMT initiation is an important consideration for future nutrition research. Studies investigating nutrition as a primary outcome of DMT, using consistent outcome measures are required for nutritional management strategies for this cohort to be appropriately tailored., (© 2024 The Author(s). Muscle & Nerve published by Wiley Periodicals LLC.)

Introduction/aims: Severe spinal deformities and previous spinal orthopedic instrumentation may result in substantial technical challenges for nusinersen delivery through lumbar puncture in patients with spinal muscular atrophy (SMA). The aim of this paper was to review our experience with ultrasound-guided cervical puncture as an alternative approach for the intrathecal administration of nusinersen., Methods: This was a retrospective medical record review of transverse interlaminar ultrasound-guided C1-C2 puncture for nusinersen delivery in SMA patients. The details of puncture, complications, and success rate of the procedure were summarized., Results: There were four patients who received a total of 13 cervical punctures for nusinersen delivery. All procedures were technically successful with no major complications. Full doses of nusinersen were delivered intrathecally., Discussion: Transverse interlaminar ultrasound-guided C1-C2 puncture is an alternative approach for administering nusinersen if lumbar puncture fails. The success of the technique requires a thorough preprocedural evaluation of cervical spine imaging, sound knowledge of the cervical sonoanatomy and careful manipulation of the needle., (© 2024 Wiley Periodicals LLC.)

Spinal Muscular Atrophy (SMA) is a neuromuscular disease caused by low levels of the Survival of Motoneuron (SMN) protein. SMN interacts with and regulates the actin-binding protein profilin2a, thereby influencing actin dynamics. Dysfunctional actin dynamics caused by SMN loss disrupts neurite outgrowth, axonal pathfinding, and formation of functional synapses in neurons. Whether the SMN protein directly interacts with and regulates filamentous (F-) and monomeric globular (G-) actin is still elusive. In a quantitative single cell approach, we show that SMN loss leads to dysregulated F-/G-actin fractions. Furthermore, quantitative assessment of cell morphology suggests an F-actin organizational defect. Interestingly, this is mediated by an interaction of SMN with G- and F-actin. In co-immunoprecipitation, in-vitro pulldown and co-localization assays, we elucidated that this interaction is independent of the SMN-profilin2a interaction. Therefore, we suggest two populations being relevant for functional actin dynamics in healthy neurons: SMN-profilin2a-actin and SMN-actin. Additionally, those two populations may influence each other and therefore regulate binding of SMN to actin. In SMA, we showed a dysregulated co-localization pattern of SMN-actin which could only partially rescued by SMN restoration. However, dysregulation of F-/G-actin fractions was reduced by SMN restoration. Taken together, our results suggest a novel molecular function of SMN in binding to actin independent from SMN-profilin2a interaction., (© 2024 Federation of American Societies for Experimental Biology.)

Background: 5q spinal muscular atrophy (SMA) is a progressive autosomal recessive motor neuron disease., Objective: We aimed to assess the effects of nusinersen on motor function and electrophysiological parameters in adolescent and adult patients with 5q SMA., Methods: Patients with genetically confirmed 5q SMA were eligible for inclusion, and clinical data were collected at baseline (V1), 63 days (V4), 180 days (V5), and 300 days (V6). The efficacy of nusinersen was monitored by encompassing clinical assessments, including the Revised Upper Limb Module (RULM), Hammersmith Functional Motor Scale Expanded (HFMSE), 6-Minute Walk Test (6MWT), and percent-predicted Forced Vital Capacity in sitting position (FVC%) and Compound Muscle Action Potential (CMAP) amplitude. The patients were divided into "sitter" and "walker" subgroups according to motor function status., Results: 54 patients were screened, divided into "sitter" (N = 22) and "walker" (N = 32), with the mean age at baseline of 27.03 years (range 13-53 years). The HFMSE in the walker subgroup increased significantly from baseline to V4 (mean change +2.32-point, P = 0.004), V5 (+3.09, P = 0.004) and V6 (+4.21, P = 0.005). The patients in both the sitter and walker subgroup had no significant changes in mean RULM between V1 and the following time points. Significant increases in CMAP amplitudes were observed in both upper and lower limbs after treatment. Also, patients with RULM ≥ 36 points showed significant CMAP improvements. Our analysis predicted that patients with CMAP amplitudes of trapezius ≥ 1.76 mV were more likely to achieve significant motor function improvements., Conclusions: Nusinersen effectively improves motor function and electrophysiological data in adolescent and adult patients with SMA. This is the first report on the CMAP amplitude changes in the trapezius after treatment in patients with SMA. The CMAP values effectively compensate for the ceiling effect observed in the RULM, suggesting that CMAP could serve as an additional biomarker for evaluating treatment efficacy., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction/aims: Following the approval of risdiplam, there are more possibilities for disease-modifying therapy (DMT) in children with spinal muscular atrophy (SMA). Non-treatment-naïve subjects with SMA involved in the JEWELFISH study, designed to evaluate the safety and tolerability of risdiplam, were required to undergo a washout period before receiving risdiplam. This study aims to investigate the safety of administering risdiplam in patients within 90 days of receiving treatment with nusinersen., Methods: Data were collected on SMA patients who had undergone treatment with nusinersen, and who then received risdiplam within 90 days of their last dose of nusinersen, including demographic characteristics, information on treatment with nusinersen and risdiplam, adverse events, and laboratory assessments in a follow-up period of 90 days, presented as median (range)., Results: A total of 15 children with SMA were reported, including 8 males and 7 females. The median number of doses of previous nusinersen treatment received was 8 (6-17) doses, and the median age at first risdiplam treatment was 4.3 (1.9-11.2) years. Specifically, 8 children received risdiplam 30 days or less after their most recent nusinersen treatment, 2 at 31-60 days after nusinersen, and 5 at 61-89 days post-nusinersen. Adverse events of pyrexia, pneumonia, vomiting and rash were reported in 4 patients., Discussion: Our study showed good safety data on patients who received risdiplam following nusinersen within the washout period of 90 days. This supplements the JEWELFISH study in the era of DMT, providing additional guidance for clinicians, but additional data from other centers is needed., (© 2024 Wiley Periodicals LLC.)

Introduction/aims: Fatigue (subjective perception) and fatigability (objective motor performance worsening) are relevant aspects of disability in individuals with spinal muscular atrophy (SMA). The effect of nusinersen on fatigability in SMA patients has been investigated with conflicting results. We aimed to evaluate this in adult with SMA3., Methods: We conducted a multicenter retrospective cohort study, including adult ambulant patients with SMA3, data available on 6-minute walk test (6MWT) and Hammersmith Functional Motor Scale-Expanded (HFMSE) at baseline and at least at 6 months of treatment with nusinersen. We investigated fatigability, estimated as 10% or higher decrease in walked distance between the first and sixth minute of the 6MWT, at baseline and over the 14-month follow-up., Results: Forty-eight patients (56% females) were included. The 6MWT improved after 6, 10, and 14 months of treatment (p < 0.05). Of the 27 patients who completed the entire follow-up, 37% improved (6MWT distance increase ≥30 m), 48.2% remained stable, and 14.8% worsened (6MWT distance decline ≥30 m). Fatigability was found at baseline in 26/38 (68%) patients and confirmed at subsequent time points (p < 0.05) without any significant change over the treatment period. There was no correlation between fatigability and SMN2 copy number, sex, age at disease onset, age at baseline, nor with 6MWT total distance and baseline HFMSE score., Discussion: Fatigability was detected at baseline in approximately 2/3 of SMA3 walker patients, without any correlation with clinical features, included motor performance. No effect on fatigability was observed during the 14-month treatment period with nusinersen., (© 2024 The Author(s). Muscle & Nerve published by Wiley Periodicals LLC.)

Risdiplam, the first oral therapy approved for spinal muscular atrophy and made globally available in 2021, necessitates a highly sensitive and straightforward assay for therapeutic drug monitoring. This is crucial to manage potential toxicities linked to drug concentrations and supervise dosing regimens. A cutting-edge ultra-high performance liquid chromatography-tandem mass spectrometry bioassay for risdiplam in human serum has been developed. In this method, analytes were separated on a Phenomenex Kinetex XB C 18 column using a 6.5-min gradient elution after a single-step protein precipitation. MS detection was conducted via electrospray ionization in positive mode with selected reaction monitoring. The validated range for risdiplam was determined to be 1.95-125.00 ng/mL. The precision and accuracy of intra- and inter-batch analyses were within ±15%. The novel method met all other established criteria. This assay holds promise for monitoring drug concentrations and guiding clinical decisions in patients with spinal muscular atrophy., (© 2024 John Wiley & Sons, Ltd.)

Objective: Spinal and bulbar muscular atrophy (SBMA) is characterized by slow, progressive bulbar and limb muscle weakness; however, the pattern of progression of muscle fat infiltration remains unclear. We assessed the progression of muscle involvement in 81 patients with SBMA using whole-body muscle magnetic resonance imaging (MRI), alongside clinical and laboratory findings., Methods: This prospective study included patients with genetically confirmed SBMA who underwent whole-body muscle MRI. We analyzed muscle fat infiltration and the pattern of involved muscles using cluster analysis, visualizing the sequential progression of fat infiltration. Muscle clusters demonstrated correlation with clinical scales and laboratory findings. Additionally, linear regression analysis was performed to identify the MRI section most strongly associated with 6-minute walk test (6MWT)., Results: We included 81 patients with SBMA (age = 54.3 years). After categorizing the patients into 6 clusters based on the pattern of muscle fat infiltration, we observed that muscle involvement began in the posterior calf and progressed to the posterior thigh, pelvis, trunk, anterior thigh, medial thigh, anterior calf, and upper extremity muscles. These muscle clusters correlated significantly with disease duration (τ = 0.47, p < 0.001), 6MWT (τ = -0.49, p < 0.001), and serum creatinine level (τ = -0.46, p < 0.001). The whole-body MRI indicated the thigh as the section most significantly correlated with 6MWT., Interpretation: We used whole-body muscle MRI to determine the sequential progression of the fat infiltration in SBMA. Our findings may enable the identification of objective and reliable imaging outcome measures in the study of the natural history or future clinical trials of SBMA. ANN NEUROL 2024;95:596-606., (© 2023 American Neurological Association.)

The 5q Spinal Muscular Atrophy (SMA) is a hereditary autosomal recessive disease caused by defects in the survival motor neuron ( SMN1 ) gene encoding survival motor neuron (SMN) protein. Currently, it is the leading cause of infantile mortality worldwide. SMA is a progressive neurodegenerative disease with "continuum of clinical severity", which can be modulated by genetic and epigenetic factors known as disease modifiers (DMs). Individuals (even siblings) with the same defects in SMN1 gene might have strikingly different types of SMA, supposedly due to the impact of DMs. There are several therapeutic options for SMA, all of them focusing on the restoration of the SMN protein levels to normal. Determining DMs and the pathways in which they are involved might aid in enhancing existing curative approaches. Furthermore, DMs might become novel therapeutic targets or prognostic biomarkers of the disease. This narrative review provides a brief overview of the genetics and pathobiology of SMA, and its bona fide modifiers. We describe novel, emerging DMs, approaches and tools used to identify them, as well as their potential mechanisms of action and impact on disease severity. We also propose several disease-modifying molecular mechanisms which could provide a partial explanation of the staggering variability of SMA phenotypes.

Purpose: Spinal muscular atrophy (SMA) is an autosomal recessive genetic disease characterized by the loss of motor neurons in the spinal cord and brainstem, leading to muscle atrophy and weakness. To understand the diagnostic process of Korean patients with SMA, we analyzed their clinical characteristics and challenges., Materials and Methods: We conducted a retrospective study of 38 patients with SMA (9 type II and 29 type III) between January 2000 and September 2023. Clinical, laboratory, and genetic data were reviewed., Results: The median ages at symptom onset and diagnosis were 3.0 years [interquartile range (IQR): 1.0-7.3 years] and 25.0 years (IQR: 10.5-37.3 years), respectively. The median diagnostic delay was 19.6 years (IQR: 6.4-31.0 years). A significantly longer delay was observed in SMA type III patients (median: 21.0 years, IQR: 11.0-31.0 years) compared to SMA type II patients (median: 3.0 years, IQR: 0.9-21.0 years) ( p =0.021). No significant difference was observed in the number of clinic visits before diagnosis between patients with SMA type II (median: 2.0, IQR: 1.0-4.5) and those with type III (median: 2.0, IQR: 2.0-6.0, p =0.282). The number of clinic visits before diagnosis showed no significant association with the age at symptom onset and diagnosis ( p =0.998 and 0.291, respectively)., Conclusion: Our investigation is the first examination of the diagnostic journey of Korean patients with SMA. As treatments for SMA progress, the significance of an accurate diagnosis has increased, highlighting the importance of reviewing the diagnostic advancements made thus far., Competing Interests: The authors have no potential conflicts of interest to disclose., (© Copyright: Yonsei University College of Medicine 2024.)

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder due to deletion or mutation of survival motor neuron 1 (SMN1) gene. Although survival motor neuron 2 (SMN2) gene is still present in SMA patients, the production of full-length survival motor neuron (SMN) protein is insufficient owing to missing or mutated SMN1. No current disease-modifying therapies can cure SMA. The aim of this study was to explore microRNA (miRNA)-based therapies that may serve as a potential target for therapeutic intervention in delaying SMA progression or as treatment. The study screened for potentially dysregulated miRNAs in SMA fibroblast-derived iPSCs using miRNA microarray. Results from the miRNA microarray were validated using quantitative reverse transcription polymerase chain reaction. Bioinformatics analysis using various databases was performed to predict the potential putative gene targeted by hsa-miR-663a. The findings showed differential expression of hsa-miR-663a in SMA patients in relation to a healthy control. Bioinformatics analysis identified GNG7, IGF2, and TNN genes that were targeted by hsa-miR-663a to be involved in the PI3K-AKT pathway, which may be associated with disease progression in SMA. Thus, this study suggests the potential role of hsa-miR-663a as therapeutic target for the treatment of SMA patients in the near future., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc.)

Spinal muscular atrophy (SMA) is the second most common fatal genetic disease in infancy. It is caused by deletion or intragenic pathogenic variants of the causative gene SMN1, which degenerates anterior horn motor neurons and leads to progressive myasthenia and muscle atrophy. Early treatment improves motor function and prognosis in patients with SMA, but drugs are expensive and do not cure the disease. Therefore, carrier screening seems to be the most effective way to prevent SMA birth defects. In this study, we genetically analyzed 1400 samples using multiplex ligation-dependent probe amplification (MLPA) and quantitative polymerase chain reaction (qPCR), and compared the consistency of the results. We randomly selected 44 samples with consistent MLPA and qPCR results for comprehensive SMA analysis (CASMA) using a long-read sequencing (LRS)-based approach. CASMA results showed 100% consistency, visually and intuitively explained the inconsistency between exons 7 and 8 copy numbers detected by MLPA in 13 samples. A total of 16 samples showed inconsistent MLPA and qPCR results for SMN1 exon 7. CASMA was performed on all samples and the results were consistent with those of resampling for MLPA and qPCR detection. CASMA also detected an additional intragenic variant c.-39A>G in a sample with two copies of SMN1 (RT02). Finally, we detected 23 SMA carriers, with an estimated carrier rate of 1/61 in this cohort. In addition, CASMA identified the "2 + 0" carrier status of SMN1 and SMN2 in a family by analyzing the genotypes of only three samples (parents and one sibling). CASMA has great advantages over MLPA and qPCR assays, and could become a powerful technical support for large-scale screening of SMA., (© 2024. The Author(s).)

Background: The introduction of newborn screening (NBS) for spinal muscular atrophy (SMA) has increased the early diagnosis of 5q-associated SMA in presymptomatic and symptomatic preterm infants. National and international recommendations for treating preterms and newborns < 38 weeks of gestational age are unavailable. Our retrospective multicentre study aimed to evaluate the postnatal clinical course of preterm infants with 5q-associated SMA diagnosed since the implementation of NBS in Germany in 2021 and to summarize the German experience regarding the decision-making process for available treatment regimens for preterm infants with ≤ 3 survival of motor neuron 2 (SMN2) copies., Results: Twelve preterm infants with 5q-associated SMA and a mean gestational age of 34.0 weeks (range: 26.1-36.8) and birth weight of 2022 g (range: 645-3370) were reported from 8/20 German SMA NBS follow-up centers using a pseudonymized questionnaire. Confirmatory diagnosis, including SMN2 copy number, was completed on average on postnatal day 13. All patients had a biallelic deletion of exon 7 or exons 7 and 8 of the survival of motor neuron 1 (SMN1) gene, with SMN2 copy numbers of two in 10 patients and three in two patients. The neonatal course was complicated by respiratory distress due to prematurity (n = 2), sepsis (n = 2), and jaundice (n = 2). At birth, 11 preterm infants (91.6%) were presymptomatic. However, the neurological status of one patient deteriorated at five weeks of age (postconceptional age of 41.8 weeks) prior to the start of treatment. Disease-modifying treatments were initiated in all patients at a mean postconceptional age of 38.8 weeks, with the majority receiving onasemnogene abeparvovec (83.3%, including 2 patients with prior risdiplam bridge therapy). Notably, consensus among participating experts from German neuromuscular centers resulted in 83.3% of patients receiving disease-modifying treatment at term., Conclusions: Premature infants with SMA require interdisciplinary care in close collaboration with the neuromuscular center. SMA NBS facilitates early initiation of disease-modifying therapy, ideally during the presymptomatic phase, which significantly influences the prognosis of the newborn., (© 2024. The Author(s).)

Spinal muscular atrophy (SMA) is a rare degenerative disorder with loss of motor neurons caused by mutations in the SMN1 gene. Nusinersen, an antisense oligonucleotide, was approved for SMA treatment to compensate the deficit of the encoded protein SMN by modulating the pre-mRNA splicing of SMN2, the centromeric homologous of SMN1, thus inducing the production of a greater amount of biologically active protein. Here, we reported a 10-month transcriptomics investigation in 10 adult SMA who received nusinersen to search for early genetic markers for clinical monitoring. By comparing their profiles with age-matched healthy controls (HC), we also analyzed the changes in miRNA/mRNAs expression and miRNA-target gene interactions possibly associated with SMA. A multidisciplinary approach of HT-NGS followed by bioinformatics/biostatistics analysis was applied. Within the study interval, those SMA patients who showed some clinical improvements were characterized by having the SMN2/SMN1 ratio slightly increased over the time, while in the stable ones the ratio decreased, suggesting that the estimation of SMN2/SMN1 expression may be an early indicator of nusinersen efficacy. On the other hand, the expression of 38/147 genes/genetic regions DE at T0 between SMA and HC like TRADD and JUND resulted "restored" at T10. We also confirmed the dysregulation of miR-146a(-5p), miR-324-5p and miR-423-5p in SMA subjects. Of interest, miR-146a-5p targeted SMN1, in line with experimental evidence showing the key role of astrocyte-produced miR-146a in SMA motor neuron loss. Molecular pathways such as NOTCH, NF-kappa B, and Toll-like receptor signalings seem to be involved in the SMA pathogenesis., (© 2024. The Author(s).)

Spinal muscular atrophy (SMA) is a rare, genetic neurodegenerative disorder caused by insufficient production of survival motor neuron (SMN) protein. Diminished SMN protein levels lead to motor neuron loss, causing muscle atrophy and weakness that impairs daily functioning and reduces quality of life. SMN upregulators offer clinical improvements and increased survival in SMA patients, although significant unmet needs remain. Myostatin, a TGF-β superfamily signaling molecule that binds to the activin II receptor, negatively regulates muscle growth; myostatin inhibition is a promising therapeutic strategy for enhancing muscle. Combining myostatin inhibition with SMN upregulation, a comprehensive therapeutic strategy targeting the whole motor unit, offers promise in SMA. Taldefgrobep alfa is a novel, fully human recombinant protein that selectively binds to myostatin and competitively inhibits other ligands that signal through the activin II receptor. Given a robust scientific and clinical rationale and the favorable safety profile of taldefgrobep in patients with neuromuscular disease, the RESILIENT phase 3, randomized, placebo-controlled trial is investigating taldefgrobep as an adjunct to SMN upregulators in SMA (NCT05337553). This manuscript reviews the role of myostatin in muscle, explores the preclinical and clinical development of taldefgrobep and introduces the phase 3 RESILIENT trial of taldefgrobep in SMA.

Dysregulated RNA metabolism caused by SMN deficiency leads to motor neuron disease spinal muscular atrophy (SMA). Current therapies improve patient outcomes but achieve no definite cure, prompting renewed efforts to better understand disease mechanisms. The calcium channel blocker flunarizine improves motor function in Smn -deficient mice and can help uncover neuroprotective pathways. Murine motor neuron-like NSC34 cells were used to study the molecular cell-autonomous mechanism. Following RNA and protein extraction, RT-qPCR and immunodetection experiments were performed. The relationship between flunarizine mRNA targets and RNA-binding protein GEMIN5 was explored by RNA-immunoprecipitation. Flunarizine increases demethylase Kdm6b transcripts across cell cultures and mouse models. It causes, in NSC34 cells, a temporal expression of GEMIN5 and KDM6B. GEMIN5 binds to flunarizine-modulated mRNAs, including Kdm6b transcripts. Gemin5 depletion reduces Kdm6b mRNA and protein levels and hampers responses to flunarizine, including neurite extension in NSC34 cells. Moreover, flunarizine increases the axonal extension of motor neurons derived from SMA patient-induced pluripotent stem cells. Finally, immunofluorescence studies of spinal cord motor neurons in Smn -deficient mice reveal that flunarizine modulates the expression of KDM6B and its target, the motor neuron-specific transcription factor HB9, driving motor neuron maturation. Our study reveals GEMIN5 regulates Kdm6b expression with implications for motor neuron diseases and therapy.

Aim: The availability of disease-modifying therapies and newborn screening programs for spinal muscular atrophy (SMA) has generated an urgent need for reliable prognostic biomarkers to classify patients according to disease severity. We aim to identify cerebrospinal fluid (CSF) prognostic protein biomarkers in CSF samples of SMA patients collected at baseline (T0), and to describe proteomic profile changes and biological pathways influenced by nusinersen before the sixth nusinersen infusion (T302)., Methods: In this multicenter retrospective longitudinal study, we employed an untargeted liquid chromatography mass spectrometry (LC-MS)-based proteomic approach on CSF samples collected from 61 SMA patients treated with nusinersen (SMA1 n=19, SMA2 n=19, SMA3 n=23) at T0 at T302. The Random Forest (RF) machine learning algorithm and pathway enrichment analysis were applied for analysis., Results: The RF algorithm, applied to the protein expression profile of naïve patients, revealed several proteins that could classify the different types of SMA according to their differential abundance at T0. Analysis of changes in proteomic profiles identified a total of 147 differentially expressed proteins after nusinersen treatment in SMA1, 135 in SMA2, and 289 in SMA3. Overall, nusinersen-induced changes on proteomic profile were consistent with i) common effects observed in allSMA types (i.e. regulation of axonogenesis), and ii) disease severity-specific changes, namely regulation of glucose metabolism in SMA1, of coagulation processes in SMA2, and of complement cascade in SMA3., Conclusions: This untargeted LC-MS proteomic profiling in the CSF of SMA patients revealed differences in protein expression in naïve patients and showed nusinersen-related modulation in several biological processes after 10 months of treatment. Further confirmatory studies are needed to validate these results in larger number of patients and over abroader timeframe., (© 2024. The Author(s).)

Objective. To evaluate electrical impedance myography (EIM) in conjunction with machine learning (ML) to detect infantile spinal muscular atrophy (SMA) and disease progression. Approach . Twenty-six infants with SMA and twenty-seven healthy infants had been enrolled and assessed with EIM as part of the NeuroNEXT SMA biomarker study. We applied a variety of modern, supervised ML approaches to this data, first seeking to differentiate healthy from SMA muscle, and then, using the best method, to track SMA progression. Main Results. Several of the ML algorithms worked well, but linear discriminant analysis (LDA) achieved 88.6% accuracy on subject muscles studied. This contrasts with a maximum of 60% accuracy that could be achieved using the single or multifrequency assessment approaches available at the time. LDA scores were also able to track progression effectively, although a multifrequency reactance-based measure also performed very well in this context. Significance. EIM enhanced with ML promises to be effective for providing effective diagnosis and tracking children and adults with SMA treated with currently available therapies. The normative trends identified here may also inform future applications of the technology in very young children. The basic analyses applied here could also likely be applied to other neuromuscular disorders characterized by muscle atrophy., (© 2024 Institute of Physics and Engineering in Medicine. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

The spinal muscular atrophy (SMA) phenotype strongly correlates with the SMN2 gene copy number. However, the severity and progression of the disease vary widely even among affected individuals with identical copy numbers. This study aimed to investigate the impact of genetic variability in oxidative stress, inflammatory, and neurodevelopmental pathways on SMA susceptibility and clinical progression. Genotyping for 31 genetic variants across 20 genes was conducted in 54 SMA patients and 163 healthy controls. Our results revealed associations between specific polymorphisms and SMA susceptibility, disease type, age at symptom onset, and motor and respiratory function. Notably, the TNF rs1800629 and BDNF rs6265 polymorphisms demonstrated a protective effect against SMA susceptibility, whereas the IL6 rs1800795 was associated with an increased risk. The polymorphisms CARD8 rs2043211 and BDNF rs6265 were associated with SMA type, while SOD2 rs4880, CAT rs1001179, and MIR146A rs2910164 were associated with age at onset of symptoms after adjustment for clinical parameters. In addition, GPX1 rs1050450 and HMOX1 rs2071747 were associated with motor function scores and lung function scores, while MIR146A rs2910164, NOTCH rs367398 SNPs, and GSTM1 deletion were associated with motor and upper limb function scores, and BDNF rs6265 was associated with lung function scores after adjustment. These findings emphasize the potential of genetic variability in oxidative stress, inflammatory processes, and neurodevelopmental pathways to elucidate the complex course of SMA. Further exploration of these pathways offers a promising avenue for developing personalized therapeutic strategies for SMA patients., (© 2024. The Author(s).)

Background: Oral function tests have been shown to reliably detect impaired bulbar function in adults with spinal muscular atrophy (SMA). Although not routinely recorded, it is known that persons with SMA are affected to varying degrees. Detecting differences in bite and tongue force, endurance, and maximum mouth opening has become particularly promising since the introduction of causal therapy for SMA. This study aimed to compare oral function among adult persons with SMA with different SMA types, walking abilities, and treatment status to a healthy control group., Methods: Data from oral function tests conducted on 58 persons with SMA and 45 healthy individuals were analyzed. Differences in oral function between SMA subgroups were pairwise tested and compared to the healthy control group using Wilcoxon rank sum tests., Results: In an overall comparison, three out of five oral function tests revealed lower values for the SMA group compared to the control group. Subgroup analyses indicated lower scores for most oral function tests in non-ambulatory, untreated patients with SMA type 2 compared to controls. Ambulatory, treated patients with SMA type 3 achieved strength and endurance values comparable to those of healthy individuals., Conclusions: The impairment of oral function varies across persons with SMA. Routine measurement of oral function is warranted to determine individual bulbar involvement stages. Further evaluation should be scheduled if indicators such as restricted maximum mouth opening arise. Trial registration DRKS, DRKS00015842. Registered 30 July 2019, https://drks.de/register/de/trial/DRKS00015842/preview ., (© 2024. The Author(s).)