Childhood spinal muscular atrophy: controversies and challenges. Lancet Neurol. 2012;11:443-452. [PMID: 22516079 DOI: 10.1016/s1474-4422(12)70061-3]

Spinal presentations in children with type 1 spinal muscular atrophy on nusinersen treatment across the SMA-REACH UK network: a retrospective national observational study

BACKGROUND

Prior to the introduction of disease-modifying treatments (DMTs), children with type 1 spinal muscular atrophy (SMA) typically did not survive beyond the age of 2 years; management was mainly palliative. Novel therapies have made this a treatable condition, resulting in increased life expectancy and more time spent upright. Survival and improved function mean spinal asymmetry is a new complication with limited data on its prevalence and severity and no current guidelines on management and treatment. This study aimed to evaluate the spinal presentation and management of type 1 SMA children on nusinersen across the SMA-REACH UK network.

METHODS

Spinal presentation and management of 80 children (age range 4 months-14 years, median 4 years 2 months) with type 1 SMA on nusinersen across the SMA-REACH UK network were reviewed through retrospective data analysis.

RESULTS

There were 60 type 1 children who developed a spinal asymmetry, of which 40 had kyphosis and 50 used a supportive thoraco-lumbar-sacral orthosis (TLSO). TLSOs were predominantly a one-piece jacket with abdominal hole, advised to be worn when upright during the day. Reduced neck range of movement was found in 33, 1 of these had plagiocephaly and 5 had torticollis. Of those with reduced neck range of movement, 26 (79%) had spinal asymmetry. Spinal surgery was performed in 7.

CONCLUSIONS

Our study confirms high prevalence of spinal asymmetry in this cohort, requiring long-term management planning. It provides information on presentation and treatment options, facilitating development of guidelines for these new complications observed in children surviving longer with DMTs.

Effect of nusinersen on pulmonary function in children with spinal muscular atrophy in the plateau region: A pilot study

Background

The drug nusinersen is applied to improve motor function in patients with spinal muscle atrophy (SMA). However, research on the effects of this treatment on lung function is lacking.

Aim

To investigate the effect of nusinersen on lung function in children with SMA in the Plateau.

Methods

A total of 20 patients with SMA (types 1, 2, or 3) who started nusinersen treatment at the Department of Pediatrics at Yunnan First People's Hospital from March 2022 and February 2024 were studied. A retrospective study was conducted to investigate changes in lung function parameters (including forced vital capacity, forced expiratory volume at 1 s, forced expiratory volume at 1 s/forced vital capacity, and peak expiratory flow) in patients with SMA treated with nusinersen.

Results

20 patients (13 male, 7 female; aged 5-16 years) were enrolled, including 2, 9, and 9 with SMA types 1, 2, and 3, respectively. The mean value of FVC % and FEV1/FVC % did not decrease further following nusinersen treatment in any patients. The mean value of FEV1% was 4.4 % and 5.0 % higher than before treatment in all patients (P = 0.03), and those with type 2 SMA (P = 0.04), respectively. The overall mean PEF % did not decrease any further after treatment. However, the average level in the type 2 group increased by 2.9 % (P = 0.03).

Conclusion

Patients with SMA, particularly those classified as type 2, showed a trend of improvement in lung function following nusinersen treatment.

Patient-specific responses to SMN2 splice-modifying treatments in spinal muscular atrophy fibroblasts

The availability of three therapies for the neuromuscular disease spinal muscular atrophy (SMA) highlights the need to match patients to the optimal treatment. Two of these treatments (nusinersen and risdiplam) target splicing of SMN2, but treatment outcomes vary from patient to patient. An incomplete understanding of the complex interactions among SMA genetics, SMN protein and mRNA levels, and gene-targeting treatments, limits our ability to explain this variability and identify optimal treatment strategies for individual patients. To address this, we analyzed responses to nusinersen and risdiplam in 45 primary fibroblast cell lines. Pre-treatment SMN2-FL, SMN2Δ7 mRNA, and SMN protein levels were influenced by SMN2 copy number, age, and sex. After treatment, SMN and mRNA levels were more heterogeneous. In 43% of patients, response to both therapies was similar, but in 57% one treatment led to a significantly higher SMN increase than the other treatment. Younger age, higher SMN2 copy number, and higher SMN levels before treatment predicted better in vitro efficacy. These findings showcase patient-derived fibroblasts as a tool for identifying molecular predictors for personalized treatment.

Usability and Safety of the ATLAS 2030 Robotic Gait Device in Children with Cerebral Palsy and Spinal Muscular Atrophy

PURPOSE

the purpose of this study was to evaluate the safety and usability of the ATLAS 2030 in children with Cerebral Palsy (CP) and Spinal Muscular Atrophy (SMA).

MATERIALS AND METHODS

the sample consisted of six children, three with CP and three with SMA, who received eight sessions of robot-assisted gait therapy. Safety was measured by the presence of adverse events. Usability was measured by spatiotemporal parameters, the Six-Minute Walking Test (6MWT), and the time needed for donning and doffing, as well as satisfaction questionnaires administered to therapists and patients.

RESULTS

no serious adverse events were reported. The average cadence and number of steps per session increased throughout sessions, as well as the distance covered in the 6MWT, both in participants with CP and SMA. The mean donning time at the end of the study was 4.6 ± 1.3 min, and only one therapist was necessary to carry out all of the sessions. Satisfaction was considered high by both children and therapists.

CONCLUSIONS

the ATLAS 2030 was shown to be safe for children with CP and SMA. The usability of the device was good, since a progression in the spatiotemporal parameters was observed throughout the sessions, and patient and therapist satisfaction were high.

Longitudinal data collection in pediatric and adult patients with 5q spinal muscular atrophy in Latin America: LATAM RegistrAME study - a clinical registry study protocol

Spinal muscular atrophy is a rare hereditary neurodegenerative disease characterized by progressive motor neuron loss. The most common form of SMA is linked to 5q (5q-SMA) and is classified into subtypes according to the age of onset and maximum motor function achieved. The severity ranges from progressive infantile paralysis and premature death (type 1) to limited motor neuron loss in adults (type 4). The LATAM RegistrAME protocol is an observational, retrospective, prospective international multicenter clinical registry study involving Latin Americans. We will include 5q-SMA patients across all age groups, from pediatric to adult, to describe their clinical characteristics and disease progression. The protocol will use an international clinical research form based on the Treat Neuromuscular Disease Global Academic Network (TREAT-NMD), which focuses on advancing research on neuromuscular disorders in patients with spinal muscular atrophy. The study will include six countries in Latin America, sampling a total of 415 patients with SMA and 5q-SMA types 1, 2, 3, and 4 of all ages and both sexes who have genetically confirmed 5q-SMA. The mean follow-up period was 24 months. The primary outcomes will be the description of general clinical characteristics, access to medications capable of modifying the course of the disease, functional assessments, motor milestones, and ventilatory support. This study will provide insights into 5q spinal muscular atrophy patients in Latin America to better understand their clinical characteristics, use of medications, and outcomes while supporting further clinical management protocols and clinical trials. ClinicalTrials.gov Identifier: NCT05475691.

Performance fatigability in adults with spinal muscular atrophy treated long-term with nusinersen

INTRODUCTION/AIMS

Persons with spinal muscular atrophy (pwSMA) report progressive muscle weakness but also reduced endurance when performing repetitive tasks in daily life, referred to as "performance fatigability" (PF). Data regarding the effects of the new disease-modifying drugs on PF are scarce. Thus, our main objective was to examine PF in adult ambulatory pwSMA treated long-term with nusinersen.

METHODS

Six-minute walk test (6MWT) data from 14 adult pwSMA treated with nusinersen for up to 70 months were retrospectively analyzed to determine PF. Performance fatigability was defined as the percentage change in the distance covered between the last and first minute of the 6MWT. In addition, relationships between PF and other clinical features were assessed.

RESULTS

Performance fatigability was found in 12/14 pwSMA (85.7%) prior to treatment. The mean distance walked in the sixth minute (71.1 m) was shorter than the distance covered in the first minute (81.8 m), corresponding to a mean PF of 13.1% (95% confidence interval (CI): 6.5-19.6, p = .0007). During treatment with nusinersen, there was a mean reduction in PF of 5.6% (95% CI: -10.0 to -1.3, p = .0148). We found no relationship between PF and fatigue as measured by the Fatigue Severity Scale.

DISCUSSION

This study demonstrates the presence of PF as an independent component of motor impairment and as a potential therapeutic target in our cohort of adult ambulatory pwSMA. Furthermore, the observations in our cohort suggest that nusinersen may have a beneficial effect on PF.

Nutrition outcomes of disease modifying therapies in spinal muscular atrophy: A systematic review

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.

Secondary outcomes of scoliosis surgery in disease-modifying treatment-naïve patients with spinal muscular atrophy type 2 and nonambulant type 3

INTRODUCTION/AIMS

Available studies on scoliosis surgery in spinal muscular atrophy (SMA) have focused on the primary outcome of the procedure-the correction of the curve-whereas research focusing on secondary outcomes is scarce. We aimed to investigate postsurgical changes in respiratory function, motor function, weight, pain, and satisfaction.

METHODS

We retrospectively reviewed the clinical notes of 32 disease-modifying treatment-naïve patients (26 SMA2, 6 nonambulant SMA3). We also performed investigator-developed phone interviews and conducted a focus group with families on postsurgical satisfaction.

RESULTS

Mean annual rate of forced vital capacity percent decline improved in SMA2: -3.2% postsurgery versus -6.9% presurgery (p < .001), with similar trajectories in SMA3. Gross motor functional scores (Hammersmith Functional Motor Scale) available in 12/32 dropped immediately after surgery: median loss of 6.5 points, with relatively spared upper limb function. Weight z-scores postsurgery dropped in 16/32, requiring food supplements (5/16); one/16 lost >5% of total weight requiring gastrostomy. Postsurgical pain was frequently reported, especially hip pain (13/32). Overall, 10/10 patients/parents participating in the phone interview rated the procedure as very successful for posture and physical appearance. Nonetheless, 7/10 reported postsurgical pain, reduced mobility, and unmet care needs. The seven patients/parents attending the focus group highlighted lack of intensive physiotherapy programs, occupational therapy assistance, and psychological support as postsurgical unmet care needs.

DISCUSSION

This study reports a positive impact of scoliosis surgery on respiratory function and overall satisfaction with posture and physical appearance. The observed negative impact on the other outcomes highlights the importance of multidisciplinary approaches to improve postoperative management.

Genetic Variability in Oxidative Stress, Inflammatory, and Neurodevelopmental Pathways: Impact on the Susceptibility and Course of Spinal Muscular Atrophy

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.

In Search of Spinal Muscular Atrophy Disease Modifiers

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.

Experiences and the psychosocial situation of parental caregivers of children with spinal muscular atrophy against the background of new treatment options: a qualitative interview study

BACKGROUND

Spinal muscular atrophy is a rare neurodegenerative disorder in children which leads untreated to muscle wasting, respiratory impairments, and a shortened life expectancy. Parents as primary caregivers are often physically and psychologically burdened. In recent years, new and promising treatment options have been approved, but it remains unclear if they have an impact on the psychosocial situation of affected families.

OBJECTIVES

The aim of this study was to explore the views and experiences of parents as informal caregivers of children with SMA in the course of the disease against the background of new treatment options (Spinraza® or Zolgensma®).

METHODS

We conducted qualitative interviews with 27 parents of children with SMA treated with Spinraza® and Zolgensma® from April to September 2020. The analysis was done using thematic analysis and reported according to the COREQ criteria.

RESULTS

The data analysis resulted in three main themes: a) caregiver burden and negative consequences for families, b) resources and protective aspects, c) psychosocial care needs. The results are discussed against the background of new treatment options and previous models of supportive care needs. Parental caregivers of affected children face multiple burdens in different stages of the child's disease progression.

CONCLUSION

Although new treatment options for SMA showed observable effects for most parents, the main caregiver burden and reported symptoms were attributable to the overburdening care tasks. To unburden families, more screening for unmet needs, family-centered help services, professional caregivers, childcare, and sufficient financial support are needed.

Acceptability, validity and responsiveness of inertial measurement units for assessing motor recovery after gene therapy in infants with early onset spinal muscular atrophy: a prospective cohort study

BACKGROUND

Onasemnogene abeparvovec gene replacement therapy (GT) has changed the prognosis of patients with spinal muscular atrophy (SMA) with variable outcome regarding motor development in symptomatic patients. This pilot study evaluates acceptability, validity and clinical relevance of Inertial Measurement Units (IMU) to monitor spontaneous movement recovery in early onset SMA patients after GT.

METHODS

Clinical assessments including CHOPINTEND score (the gold standard motor score for infants with SMA) and IMU measurements were performed before (M0) and repeatedly after GT. Inertial data was recorded during a 25-min spontaneous movement task, the child lying on the back, without (10 min) and with a playset (15 min) wearing IMUs. Two commonly used parameters, norm acceleration 95th centile (||A||_95) and counts per minute (||A||_CPM) were computed for each wrist, elbow and foot sensors.

RESULTS

23 SMA-patients were included (mean age at diagnosis 8 months [min 2, max 20], 19 SMA type 1, three type 2 and one presymptomatic) and 104 IMU-measurements were performed, all well accepted by families and 84/104 with a good child participation (evaluated with Brazelton scale). ||A||_95 and ||A||_CPM showed high internal consistency (without versus with a playset) with interclass correlation coefficient for the wrist sensors of 0.88 and 0.85 respectively and for the foot sensors of 0.93 and 0.91 respectively. ||A||_95 and ||A||_CPM were strongly correlated with CHOPINTEND (r for wrist sensors 0.74 and 0.67 respectively and for foot sensors 0.61 and 0.68 respectively, p-values < 0.001). ||A||_95 for the foot, the wrist, the elbow sensors and ||A||_CPM for the foot, the wrist, the elbow sensors increased significantly between baseline and the 12 months follow-up visit (respective p-values: 0.004, < 0.001, < 0.001, 0.006, < 0.001, < 0.001).

CONCLUSION

IMUs were well accepted, consistent, concurrently valid, responsive and associated with unaided sitting acquisition especially for the elbow sensors. This study is the first reporting a large set of inertial sensor derived data after GT in SMA patients and paves the way for IMU-based follow-up of SMA patients after treatment.

Oral functions in adult persons with spinal muscular atrophy compared to a healthy control group: a prospective cross-sectional study with a multimodal approach

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 .

Low bone mineral density and its influencing factors in spinal muscular atrophy without disease-modifying treatment: a single-centre cross-sectional study

BACKGROUND

Children with spinal muscular atrophy (SMA) are at risk of low bone mineral density (BMD) and bone fragility. This study aims to assess lumbar spine BMD measured by quantitative computed tomography (QCT) and investigate influencing factors of low BMD in children with SMA without disease-modifying treatment.

METHODS

Demographic data, laboratory parameters, QCT data, and data on spinal radiographs were collected. A linear regression model was carried out to explore the correlations between BMD and its related factors.

RESULTS

Sixty-six patients with SMA who had complete records between July 2017 and July 2023 were analyzed, with SMA with a mean age of 5.4 years (range, 2.4-9.7 years), including type 1 in 14, type 2 in 37, and type 3 in 15. 28.8% of patients (19/66) were diagnosed with low BMD (Z-scores ≤ - 2), and the mean BMD Z-scores on QCT was - 1.5 ± 1.0. In our model, BMD Z-scores was associated with age (β=-0.153, p = 0.001). SMA phenotype and serum bone metabolism markers, such as serum phosphorus (P), alkaline phosphatase (ALP) and 25-Hydroxyvitamin D (25-OH-D) levels did not independently predict low BMD. ROC analysis showed that the age ≥ 6.3 years predicts a Z-scores ≤ -2.0 with a sensitivity of 68.4% and a specificity of 68.1%.

CONCLUSIONS

Low BMD were highly prevalent in children with SMA without disease-modifying treatment in our centre. Regular monitoring of BMD is necessary for all types of SMA children, especially those aged ≥ 6.3 years.

Evaluating the clinical efficacy of a long-read sequencing-based approach for carrier screening of spinal muscular atrophy

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.

Real-world multidisciplinary outcomes of onasemnogene abeparvovec monotherapy in patients with spinal muscular atrophy type 1: experience of the French cohort in the first three years of treatment

BACKGROUND

Spinal muscular atrophy type 1 (SMA1) is the most severe and early form of SMA, a genetic disease with motor neuron degeneration. Onasemnogene abeparvovec gene transfer therapy (GT) has changed the natural history of SMA1, but real-world data are scarce.

METHODS

A French national expert committee identified 95 newly diagnosed treatment-naive SMA1 patients between June 2019 and June 2022. We prospectively report on children treated with GT as the first and only therapy who had more than one-year of follow-up.

RESULTS

Forty-six SMA1 patients received GT. Twelve patients received other treatments. Patients with respiratory insufficiency were oriented toward palliative care after discussion with families. Twenty-nine of the treated patients with more than 12 months of follow-up were included in the follow-up analysis. Among them, 17 had 24 months of follow-up. The mean age at treatment was 7.5 (2.1-12.5) months. Twenty-two patients had two SMN2 copies, and seven had three copies. One infant died in the month following GT due to severe thrombotic microangiopathy, and another died due to respiratory distress. Among the 17 patients with 24 months of follow-up, 90% required spinal bracing (15/17), three patients required nocturnal noninvasive ventilation, and two needed gastrostomy. Concerning motor milestones at the 24-month follow-up, all patients held their head, 15/17 sat for 30 s unassisted, and 12/17 stood with aid. Motor scores (CHOPINTEND and HINE-2) and thoracic circumference significantly improved in all patients.

CONCLUSIONS

Our study shows favorable motor outcomes and preserved respiratory and feeding functions in treatment-naive SMA1 infants treated by GT as the first and only therapy before respiratory and bulbar dysfunctions occurred. Nevertheless, almost all patients developed spinal deformities.

Muscular MRI and magnetic resonance neurography in spinal muscular atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disease caused by the degeneration of the α-motor neurons in the anterior horn of the spinal cord. SMA is clinically characterized by progressive and symmetrical muscle weakness and muscle atrophy and ends up with systemic multisystem abnormalities. Quantitative MRI (qMRI) has the advantages of non-invasiveness, objective sensitivity, and high reproducibility, and has important clinical value in evaluating the severity of neuromuscular diseases and monitoring the efficacy of treatment. This article summarizes the clinical use of muscular MRI and magnetic resonance neurography in assessing the progress of SMA.

Rehabilitation Strategies for Patients With Spinal Muscular Atrophy in the Era of Disease-Modifying Therapy

The impact of disease-modifying therapy ranges from cure to no impact with a wide range of intermediates. In cases where the intermediate group reaches a plateau after the acquisition of some muscle strength, it is necessary to set a functional level appropriate for increased motor power and establish a long-term exercise plan to maintain it. As the disease status stabilizes and the life span increases, early nonsurgical interventions are required, such as using a standing frame to prevent joint contracture, applying a spinal brace at the early stage of scoliosis, and maintaining sitting postures that exaggerate lumbar lordosis. In cases where scoliosis and hip displacement occur and progress even after conservative managements are implemented, early referral to surgery should be considered. Oromotor activity and swallowing function are influenced not only by the effects of disease-modifying drugs, but also by post-birth experience and training. Therefore, although the feeding tube cannot be removed, it is necessary to make efforts to simulate the infant feeding development while maintaining partial oral feeding. Since the application period of non-invasive ventilators has increased, it has become more important to prevent long-term complications such as facial abrasion, skin allergy, orthodontic deformities, and maxillary flattening caused by the interface. Dual ventilator mode or interface can also be utilized.

Exploring functional strength changes during nusinersen treatment in symptomatic children with SMA types 2 and 3

The Hammersmith Functional Motor Scale-Expanded (HFMSE) is a validated outcome measure for monitoring changes in functional strength in patients with spinal muscular atrophy (SMA). The objective of this study was to explore changes in HFMSE item-scores in children with SMA types 2 and 3a treated with nusinersen over a period of six to twenty months. We stratified patients according to motor ability (sitting and walking), and calculated numbers and percentages for each specific improvement (positive score change) or decrease (negative score change) for the total group and each subgroup and calculated frequency distributions of specific score changes. Ninety-one percent of the children showed improvement in at least 1 item, twenty-eight percent showed a score decrease in 1 or more items. In the first six to twenty months of nusinersen treatment motor function change was characterized by the acquisition of the ability to perform specific tasks with compensation strategies (score changes from 0 to 1). Children with the ability to sit were most likely to improve in items that assess rolling, whilst children with the ability to walk most likely improved in items that assess half-kneeling. The ability most frequently lost was hip flexion in supine position.

Physiological Features of the Neural Stem Cells Obtained from an Animal Model of Spinal Muscular Atrophy and Their Response to Antioxidant Curcumin

The most prevalent rare genetic disease affecting young individuals is spinal muscular atrophy (SMA), which is caused by a loss-of-function mutation in the telomeric gene survival motor neuron (SMN) 1. The high heterogeneity of the SMA pathophysiology is determined by the number of copies of SMN2, a separate centromeric gene that can transcribe for the same protein, although it is expressed at a slower rate. SMA affects motor neurons. However, a variety of different tissues and organs may also be affected depending on the severity of the condition. Novel pharmacological treatments, such as Spinraza, Onasemnogene abeparvovec-xioi, and Evrysdi, are considered to be disease modifiers because their use can change the phenotypes of the patients. Since oxidative stress has been reported in SMA-affected cells, we studied the impact of antioxidant therapy on neural stem cells (NSCs) that have the potential to differentiate into motor neurons. Antioxidants can act through various pathways; for example, some of them exert their function through nuclear factor (erythroid-derived 2)-like 2 (NRF2). We found that curcumin is able to induce positive effects in healthy and SMA-affected NSCs by activating the nuclear translocation of NRF2, which may use a different mechanism than canonical redox regulation through the antioxidant-response elements and the production of antioxidant molecules.

Safety analysis of laboratory parameters in paediatric patients with spinal muscular atrophy treated with nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a progressive neurodegenerative disorder that can be treated with intrathecal nusinersen, an antisense oligonucleotide. In addition to efficacy, safety is a determining factor in the success of any therapy. Here, we aim to assess the safety of nusinersen therapy in paediatric patients with SMA.

METHODS

Laboratory data of paediatric patients with SMA who received nusinersen between October 2019 and May 2022 were retrospectively analysed.

RESULTS

During the observation period, 46 infants and children aged 2.9 months to 13.6 years received a total of 213 nusinersen doses without safety concerns. Inflammatory markers were stable throughout the study. International normalized ratio was increased by 0.09 per injection. Urea levels were increased by 0.108 mmol/L, and cystatin C decreased by 0.029 mg/L per injection. There were no significant changes in platelet count, activated partial thrombin time, creatinine levels or liver enzyme levels during treatment. The cerebrospinal fluid (CSF) leukocyte count remained stable, and total protein increased by 24.038 mg/L per injection.

CONCLUSION

Our data showed that nusinersen therapy is generally safe in children with SMA. Laboratory monitoring did not identify any persistent or significantly abnormal findings. CSF protein should be monitored to gain more insights.

A horizontal and perpendicular interlaminar approach for intrathecal nusinersen injection in patients with spinal muscular atrophy and scoliosis: an observational study

BACKGROUND

Lumbar puncture is challenging for patients with scoliosis. Previous ultrasound-assisted techniques for lumbar puncture used the angle of the probe as the needle trajectory; however, reproducing the angle is difficult and increases the number of needle manipulations. In response, we developed a technique that eliminated both the craniocaudal and lateromedial angulation of the needle trajectory to overall improve this technique. We assessed the feasibility and safety of this method in patients with scoliosis and identify factors related to difficult lumbar puncture.

METHODS

Patients with spinal muscular atrophy and scoliosis who were referred to the anesthesia department for intrathecal nusinersen administrations were included. With a novel approach that utilized patient position and geometry, lumbar puncture was performed under ultrasound guidance. Success rates, performance times and adverse events were recorded. Clinical-demographic and spinal radiographic data pertaining to difficult procedures were analyzed.

RESULTS

Success was achieved in all 260 (100%) lumbar punctures for 44 patients, with first pass and first attempt success rates of 70% (183/260) and 87% (226/260), respectively. Adverse events were infrequent and benign. Higher BMI, greater skin dural sac depth and smaller interlaminar size might be associated with greater difficulty in lumbar puncture.

CONCLUSIONS

The novel ultrasound-assisted horizontal and perpendicular interlaminar needle trajectory approach is an effective and safe method for lumbar puncture in patients with spinal deformities. This method can be reliably performed at the bedside and avoids other more typical and complex imaging such as computed tomography guided procedure.

Real-world evidence: Risdiplam in a patient with spinal muscular atrophy type I with a novel splicing mutation and one SMN2 copy

Spinal muscular atrophy (SMA), which results from the deletion or/and mutation in the SMN1 gene, is an autosomal recessive neuromuscular disorder that leads to weakness and muscle atrophy. SMN2 is a paralogous gene of SMN1. SMN2 copy number affects the severity of SMA, but its role in patients treated with disease modifying therapies is unclear. The most appropriate individualized treatment for SMA has not yet been determined. Here, we reported a case of SMA type I with normal breathing and swallowing function. We genetically confirmed that this patient had a compound heterozygous variant: one deleted SMN1 allele and a novel splice mutation c.628-3T>G in the retained allele, with one SMN2 copy. Patient-derived sequencing of 4 SMN1 cDNA clones showed that this intronic single transversion mutation results in an alternative exon (e)5 3' splice site, which leads to an additional 2 nucleotides (AG) at the 5' end of e5, thereby explaining why the patient with only one copy of SMN2 had a mild clinical phenotype. Additionally, a minigene assay of wild type and mutant SMN1 in HEK293T cells also demonstrated that this transversion mutation induced e5 skipping. Considering treatment cost and goals of avoiding pain caused by injections and starting treatment as early as possible, risdiplam was prescribed for this patient. However, the patient showed remarkable clinical improvements after treatment with risdiplam for 7 months despite carrying only one copy of SMN2. This study is the first report on the treatment of risdiplam in a patient with one SMN2 copy in a real-world setting. These findings expand the mutation spectrum of SMA and provide accurate genetic counseling information, as well as clarify the molecular mechanism of careful genotype-phenotype correlation of the patient.

Nusinersen Treatment for Spinal Muscular Atrophy: Retrospective Multicenter Study of Pediatric and Adult Patients in Kuwait

Spinal muscular atrophy is a neuromuscular genetic condition associated with progressive muscle weakness and atrophy. Nusinersen is an antisense oligonucleotide therapy approved for the treatment of 5q spinal muscular atrophy in pediatric and adult patients. The objective of this clinical case series is to describe the efficacy and safety of nusinersen in treating spinal muscular atrophy in 20 pediatric and 18 adult patients across six treatment centers in Kuwait. Functional motor assessments (Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders, Hammersmith Functional Motor Scale Expanded, and Revised Upper Limb Module) were used to assess changes in motor function following nusinersen treatment. The safety assessment involved clinical monitoring of adverse events. The results demonstrate clinically meaningful or considerable improvement in motor performance for nearly all patients, lasting over 4 years in some cases. A total of 70% of patients in the pediatric cohort and 72% of patients in the adult cohort achieved a clinically meaningful improvement in motor function following nusinersen treatment. Additionally, nusinersen was well-tolerated in both cohorts. These findings add to the growing body of evidence relating to the clinical efficacy and safety of nusinersen.

Dysfunction of proprioceptive sensory synapses is a pathogenic event and therapeutic target in mice and humans with spinal muscular atrophy

Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by a varying degree of severity that correlates with the reduction of SMN protein levels. Motor neuron degeneration and skeletal muscle atrophy are hallmarks of SMA, but it is unknown whether other mechanisms contribute to the spectrum of clinical phenotypes. Here, through a combination of physiological and morphological studies in mouse models and SMA patients, we identify dysfunction and loss of proprioceptive sensory synapses as key signatures of SMA pathology. We demonstrate that SMA patients exhibit impaired proprioception, and their proprioceptive sensory synapses are dysfunctional as measured by the neurophysiological test of the Hoffmann reflex (H-reflex). We further show that loss of excitatory afferent synapses and altered potassium channel expression in SMA motor neurons are conserved pathogenic events found in both severely affected patients and mouse models. Lastly, we report that improved motor function and fatigability in ambulatory SMA patients and mouse models treated with SMN-inducing drugs correlate with increased function of sensory-motor circuits that can be accurately captured by the H-reflex assay. Thus, sensory synaptic dysfunction is a clinically relevant event in SMA, and the H-reflex is a suitable assay to monitor disease progression and treatment efficacy of motor circuit pathology.

Nusinersen therapy changed the natural course of spinal muscular atrophy type 1: What about spine and hip?

Purpose

Spinal muscular atrophy type 1 has a devastating natural course and presents a severe course marked by scoliosis and hip subluxation in nonambulatory patients. Nusinersen, Food and Drug Administration-approved spinal muscular atrophy therapy, extends survival and enhances motor function. However, its influence on spinal and hip deformities remains unclear.

Methods

In a retrospective study, 29 spinal muscular atrophy type 1 patients born between 2017 and 2021, confirmed by genetic testing, treated with intrathecal nusinersen, and had registered to the national electronic health database were included. Demographics, age at the first nusinersen dose, total administrations, and Children's of Philadelphia Infant Test of Neuromuscular Disorders scores were collected. Radiological assessments included parasol rib deformity, scoliosis, pelvic obliquity, and hip subluxation.

Results

Mean age was 3.7 ± 1.1 (range, 2-6), and average number of intrathecal nusinersen administration was 8.9 ± 2.9 (range, 4-19). There was a significant correlation between Children's of Philadelphia Infant Test of Neuromuscular Disorders score and the number of nusinersen administration (r = 0.539, p = 0.05). The correlation between Children's of Philadelphia Infant Test of Neuromuscular Disorders score and patient age (r = 0.361) or the time of first nusinersen dose (r = 0.39) was not significant (p = 0.076 and p = 0.054, respectively). While 93.1% had scoliosis, 69% had pelvic obliquity, and 60.7% had hip subluxation, these conditions showed no significant association with patient age, total nusinersen administrations, age at the first dose, or Children's of Philadelphia Infant Test of Neuromuscular Disorders scores.

Conclusion

Disease-modifying therapy provides significant improvements in overall survival and motor function in spinal muscular atrophy type 1. However, progressive spine deformity and hip subluxation still remain significant problems in the majority of cases which would potentially need to be addressed.

Long-Term Comparative Efficacy and Safety of Risdiplam and Nusinersen in Children with Type 1 Spinal Muscular Atrophy

INTRODUCTION

Spinal muscular atrophy (SMA) is a severe genetic neuromuscular disease characterized by a loss of motor neurons and progressive muscle weakness. Children with untreated type 1 SMA never sit independently and require increasing levels of ventilatory support as the disease progresses. Without intervention, and lacking ventilatory support, death typically occurs before the age of 2 years. There are currently no head-to-head trials comparing available treatments in SMA. Indirect treatment comparisons are therefore needed to provide information on the relative efficacy and safety of SMA treatments for healthcare decision-making.

METHODS

The long-term efficacy and safety of risdiplam versus nusinersen in children with type 1 SMA was evaluated using indirect treatment comparison methodology to adjust for differences between population baseline characteristics, to reduce any potential bias in the comparative analysis. An unanchored matching-adjusted indirect comparison was conducted using risdiplam data from 58 children in FIREFISH (NCT02913482) and published aggregate nusinersen data from 81 children obtained from the ENDEAR (NCT02193074) and SHINE (NCT02594124) clinical trials with at least 36 months of follow-up.

RESULTS

Children with type 1 SMA treated with risdiplam had a 78% reduction in the rate of death, an 81% reduction in the rate of death or permanent ventilation, and a 57% reduction in the rate of serious adverse events compared with children treated with nusinersen. Children treated with risdiplam also had a 45% higher rate of achieving a Hammersmith Infant Neurological Examination, Module 2 motor milestone response and a 186% higher rate of achieving a ≥ 4-point improvement in Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders compared with children treated with nusinersen.

CONCLUSION

Long-term data supported risdiplam as a superior alternative to nusinersen in children with type 1 SMA. Video abstract available for this article. Video abstract (MP4 184542 KB).

General movements in spinal muscular atrophy type 1

PURPOSE

To investigate the motor repertoire of infants diagnosed with spinal muscular atrophy Type I (SMA Type I) without administration of any disease-modifying agent.

METHODS

Motor Optimality Score-Revised (MOS-R) was calculated from videos recorded between post-term weeks 9-17 for 22 infants with SMA Type I. The MOS-R of infants with SMA Type I was compared with those of 22 infants with cerebral palsy (CP) and 22 infants with typical development.

RESULTS

Of the infants with SMA Type I, 17 had absent fidgety movements (FMs) and 5 had sporadic FMs. Age adequate movement repertoire was absent, and the variety of movements in infants was very low. Movements were symmetrical but movements of four limbs remained on the surface level. Antigravity movements were very rare. Movement characterization was monotonous, slow speed, and small amplitude. The MOS-R of infants with SMA Type I was lower than those of infants with typical development but similar to those of infants with CP.

CONCLUSIONS

Infants with SMA Type I had a motor repertoire similar to infants with CP, while they had a poorer motor repertoire than infants with typical development in the fidgety period as evidenced by MOS-R. Central nervous system involvement in these infants with SMA Type I with absent FMs and reduced MOS-R is unknown. Further studies are needed to determine the role of problems in the afferent and efferent pathways of spinal cord and muscle atrophy in the observation of normal FMs.

Exploiting urine-derived induced pluripotent stem cells for advancing precision medicine in cell therapy, disease modeling, and drug testing

The field of regenerative medicine has witnessed remarkable advancements with the emergence of induced pluripotent stem cells (iPSCs) derived from a variety of sources. Among these, urine-derived induced pluripotent stem cells (u-iPSCs) have garnered substantial attention due to their non-invasive and patient-friendly acquisition method. This review manuscript delves into the potential and application of u-iPSCs in advancing precision medicine, particularly in the realms of drug testing, disease modeling, and cell therapy. U-iPSCs are generated through the reprogramming of somatic cells found in urine samples, offering a unique and renewable source of patient-specific pluripotent cells. Their utility in drug testing has revolutionized the pharmaceutical industry by providing personalized platforms for drug screening, toxicity assessment, and efficacy evaluation. The availability of u-iPSCs with diverse genetic backgrounds facilitates the development of tailored therapeutic approaches, minimizing adverse effects and optimizing treatment outcomes. Furthermore, u-iPSCs have demonstrated remarkable efficacy in disease modeling, allowing researchers to recapitulate patient-specific pathologies in vitro. This not only enhances our understanding of disease mechanisms but also serves as a valuable tool for drug discovery and development. In addition, u-iPSC-based disease models offer a platform for studying rare and genetically complex diseases, often underserved by traditional research methods. The versatility of u-iPSCs extends to cell therapy applications, where they hold immense promise for regenerative medicine. Their potential to differentiate into various cell types, including neurons, cardiomyocytes, and hepatocytes, enables the development of patient-specific cell replacement therapies. This personalized approach can revolutionize the treatment of degenerative diseases, organ failure, and tissue damage by minimizing immune rejection and optimizing therapeutic outcomes. However, several challenges and considerations, such as standardization of reprogramming protocols, genomic stability, and scalability, must be addressed to fully exploit u-iPSCs' potential in precision medicine. In conclusion, this review underscores the transformative impact of u-iPSCs on advancing precision medicine and highlights the future prospects and challenges in harnessing this innovative technology for improved healthcare outcomes.

Efficacy and safety of onasemnogene abeparvovec for the treatment of patients with spinal muscular atrophy type 1: A systematic review with meta-analysis

BACKGROUND

Onasemnogene abeparvovec has been approved for the treatment of spinal muscular atrophy 5q type 1 in several countries, which calls for an independent assessment of the evidence regarding efficacy and safety.

OBJECTIVE

Conduct a meta-analysis to assess the efficacy and safety of onasemnogene abeparvovec in patients diagnosed with SMA type 1, based on the available evidence.

METHODS

This article results from searches conducted on databases up to November 2022. Outcomes of interest were global survival and event-free survival, improvement in motor function and treatment-related adverse events. Risk of bias assessment and certainty of evidence were performed for each outcome. Proportional meta-analysis models were performed when applicable.

RESULTS

Four reports of three open-label, non-comparative clinical trials covering 67 patients were included. Meta-analyses of data available in a 12-month follow-up estimate a global survival of 97.56% (95%CI: 92.55 to 99.86, I2 = 0%, n = 67), an event-free survival of 96.5% (95%CI: 90.76 to 99.54, I2 = 32%, n = 66) and a CHOP-INTEND score ≥ 40 points proportion of 87.28% (95%CI: 69.81 to 97.83, I2 = 69%, n = 67). Proportion of 52.64% (95%CI: 27.11 to 77.45, I2 = 78%, n = 67) of treatment-related adverse events was estimated.

CONCLUSION

The results indicate a potential change in the natural history of type 1 SMA, but the methodological limitations of the studies make the real extent of the technology's long-term benefits uncertain.

Optimized MLPA workflow for spinal muscular atrophy diagnosis: identification of a novel variant, NC_000005.10:g.(70919941_70927324)del in isolated exon 1 of SMN1 gene through long-range PCR

BACKGROUND

Spinal muscular atrophy (SMA) is a rare autosomal recessive hereditary neuromuscular disease caused by survival motor neuron 1 (SMN1) gene deletion or mutation. Homozygous deletions of exon 7 in SMN1 result in 95% of SMA cases, while the remaining 5% are caused by other pathogenic variants of SMN1.

METHODS

We analyzed two SMA-suspected cases that were collected, with no SMN1 gene deletion and point mutation in whole-exome sequencing. Exon 1 deletion of the SMN gene was detected using Multiplex ligation-dependent probe amplification (MLPA) P021. We used long-range polymerase chain reaction (PCR) to isolate the SMN1 template, optimized-MLPA P021 for copy number variation (CNV) analysis within SMN1 only, and validated the findings via third-generation sequencing.

RESULTS

Two unrelated families shared a genotype with one copy of exon 7 and a novel variant, g.70919941_70927324del, in isolated exon 1 of the SMN1 gene. Case F1-II.1 demonstrated no exon 1 but retained other exons, whereas F2-II.1 had an exon 1 deletion in a single SMN1 gene. The read coverage in the third-generation sequencing results of both F1-II.1 and F2-II.1 revealed a deletion of approximately 7.3 kb in the 5' region of SMN1. The first nucleotide in the sequence data aligned to the 7385 bp of NG_008691.1.

CONCLUSION

Remarkably, two proband families demonstrated identical SMN1 exon 1 breakpoint sites, hinting at a potential novel mutation hotspot in Chinese SMA, expanding the variation spectrum of the SMN1 gene and corroborating the specificity of isolated exon 1 deletion in SMA pathogenesis. The optimized-MLPA P021 determined a novel variant (g.70919941_70927324del) in isolated exon 1 of the SMN1 gene based on long-range PCR, enabling efficient and affordable detection of SMN gene variations in patients with SMA, providing new insight into SMA diagnosis to SMN1 deficiency and an optimized workflow for single exon CNV testing of the SMN gene.

Gray and white matter abnormalities in children with type 2 and 3 SMA: A morphological assessment

This study investigated the changes in brain gray and white matter structure in SMA patients and their correlation with the severity of the disease. A total of 43 SMA patients (including 22 type II and 21 type III SMA patients) and 37 healthy controls were evaluated by MRI. The gray matter volume, gray matter thickness, gray matter surface area, and white matter volume of designated brain regions automatically segmented by FreeSurfer, were compared. We evaluate clinical characteristics of SMA and study the correlation between clinical characteristics and structural changes. SMA showed significant bilateral cortical superficial area loss in the frontal, parietal, and temporal lobes and global white matter volume decreases. Moreover, these patients were also found with an increased mean thickness of entire brain and right gray matter. An increased right postcentral gyrus superficial area, right central sulcus volume, and white matter volume of the right postcentral were associated with higher HFMSE scores.

CONCLUSION

Type 2 and 3 children SMA had extensive, multifocal, symmetrical gray and white matter alterations. Postcentral gyrus degeneration of SMA was associated with the severity of muscular atrophy. The lack of SMN protein possibly interacted with cerebellar structural changes in somatosensory areas.

WHAT IS KNOWN

• MRI has found brain changes in SMA patients, however, there is no unified conclusion and lack of correlation with clinical degree in children SMA with type 2-3.

WHAT IS NEW

• Type II and II children SMA had extensive, multifocal, symmetrical gray and white matter alterations. Postcentral gyrus degeneration of SMA was associated with the severity of muscular atrophy. Cerebellar structural changes in somatosensory areas may attribute to the lack of SMN protein.

Effect of nusinersen after 3 years of treatment in 57 young children with SMA in terms of SMN2 copy number or type

BACKGROUND

Spinal muscular atrophy (SMA) is a rare genetic neuromuscular disorder due to an autosomal recessive mutation in the survival motor neuron 1 gene (SMN1), causing degeneration of the anterior horn cells of the spinal cord and resulting in muscle atrophy. This study aimed to report on the 36-month follow-up of children with SMA treated with nusinersen before the age of 3 years. Changes in motor function, nutritional and ventilatory support, and orthopedic outcomes were evaluated at baseline and 36 months after intrathecal administration of nusinersen and correlated with SMA type and SMN2 copy number.

RESULTS

We found that 93% of the patients gained new motor skills during the 3 years-standing without help for 12 of 37 and walking with help for 11 of 37 patients harboring three SMN2 copies. No patients with two copies of SMN2 can stand alone or walk. Patients bearing three copies of SMN2 are more likely to be spared from respiratory, nutritional, and orthopedic complications than patients with two SMN2 copies.

CONCLUSION

Children with SMA treated with nusinersen continue to make motor acquisitions at 3 years after initiation of treatment. Children with two SMN2 copies had worse motor, respiratory, and orthopedic outcomes after 3 years of treatment than children with three copies.

Onasemnogene Abeparvovec: Post-infusion Efficacy and Safety in Patients With Spinal Muscular Atrophy (SMA)-A Fondazione Policlinico Gemelli IRCCS Experience

Objective: The term Spinal Muscular Atrophy (SMA) identifies a group of genetic disorders affecting spinal motor neurons. It is caused by the loss of the SMN1 gene, resulting in degeneration of spinal alpha motor neurons and muscle atrophy. This study is focused on innovative gene therapies with onasemnogene abeparvovec approved in Italy in March 2021 with full reimbursement by the National Health Service. The objective pursued is verify, by means of the CHOP-INTEND scores obtained, whether therapy with onasemnogene abeparvovec led to an improvement in the clinical picture of the treated subjects and any adverse reactions that occurred. Methods: this study was conducted by evaluating the scores in the different re-evaluations of individual patients treated in our hospital (Fondazione Policlinico Universitario Agostino Gemelli IRCCS - Rome) and comparing them with the results of the CL-303 study described in SPC (Summary of Product Characteristics). The data were extracted from the patients' clinical records on the AIFA (Agenzia Italiana del Farmaco - Italian Medicines Agency) registries, also collecting information on any post-infusion ADRs. Everything was then represented graphically to have a clear comparison with the data from the study registered for drug approval. Results: from the data obtained, 7 out of 8 patients improved their health status post infusion with, in some cases, a significant increase in score. Conclusions: this result allows us to understand how crucial it is to start treatment as soon as possible after the diagnosis of the condition as the greatest improvements were seen in subjects who received treatment within 2 months of birth.

Life-Saving Treatments for Spinal Muscular Atrophy: Global Access and Availability

Background and Objectives

Spinal muscular atrophy (SMA) is a neurodegenerative disorder manifesting with progressive muscle weakness and atrophy. SMA type 1 used to be fatal within the first 2 years of life, but is now treatable with therapies targeting splicing modification and gene replacement. Nusinersen, risdiplam, and onasemnogene abeparvovec-xioi improve survival, motor strength, endurance, and ability to thrive, allowing many patients to potentially attain a normal life; all have been recently approved by major regulatory agencies. Although these therapies have revolutionized the world of SMA, they are associated with a high economic burden, and access to these therapies is limited in some countries. The primary objective of this study was to compare the availability and implementation of treatment of SMA from different regions of the world.

Methods

In this qualitative study, we surveyed health care providers from 21 countries regarding their experiences caring for patients with SMA. The main outcome measures were provider survey responses on newborn screening, drug availability/access, barriers to treatment, and related questions.

Results

Twenty-four providers from 21 countries with decades of experience (mean 26 years) in treating patients with SMA responded to the survey. Nusinersen was the most available therapy for SMA. Our survey showed that while genetic testing is usually available, newborn screening is still unavailable in many countries. The provider-reported treatment cost also varied between countries, and economic burden was a major barrier in treating patients with SMA.

Discussion

Overall, this survey highlights the global inequality in managing patients with SMA. The spread of newborn screening is essential in ensuring improved access to care for patients with SMA. With the advancement of neurotherapeutics, more genetic diseases will soon be treatable, and addressing the global inequality in clinical care will require novel approaches to mitigate such inequality in the future.

[Natural history of spinal muscular atrophy type I]

Spinal muscular atrophy (SMA) is a group of genetically heterogeneous neuromuscular diseases characterized by the progressive loss of motor neurons in the anterior horns of the spinal cord. The prevalence of SMA is approximately 1 in 10.000 live births. The cause of SMA is a mutation in the SMN1 gene, which encodes a neuronal survival protein. The phenotype of the disease depends on the number of copies of the SMN2 gene, which encodes an unstable isoform of the same protein. Despite the emergence of new drugs that increase SMN protein levels, there remains a need to collect and systematize data on the natural history of the disease to evaluate the effectiveness of new therapeutic approaches. This review analyzed the results of 12 retrospective and prospective studies over the past 16 years, which examined the natural history of the disease in 646 children with SMA type I. The mean age of onset of symptoms was 2.1±0.7 months, with the first documented symptoms being muscle hypotonia, respiratory distress, and feeding difficulties. The mean age at death was 19.2±10.1 months, the median age at achievement of the composite endpoint (defined as death or the date of initiation of long-term respiratory support) was 7.7 months (95% CI 3.8; 13.9). For 310 children, the number of copies of the SMN2 gene was known, 81.5% of them had 2 copies, 3.7% had 1 copy, 14.5% had 3 copies, 0.3% had 4 copies. Age at death varied according to SMN2 gene copy number, children with three copies of the SMN2 gene lived on average significantly longer than children with two copies of SMN2 (22.7 months versus 6.6 months). Life expectancy was also positively influenced by the use of maintenance therapy, tracheostomy or gastrostomy.

Multidisciplinary physical rehabilitation program of individuals with spinal muscular atrophy in an inclusive school setting

Spinal muscular atrophy (SMA) is a neuromuscular ailment that leads to the deprivation of motor neurons in the spinal cord, producing denervation and muscle weakness. This case report explains how a patient with type 2 SMA used a therapeutic exercise rehabilitation program in a school environment. Motor functions were assessed by Gross Motor Function Measure-88 (GMFM-88), Manual Muscle Testing (MMT), and Hammersmith Functional Motor Scale (HFMS), which is validated and reliable. This study employed a repeated pre-test post-test measures design. During a year of treatment sessions, the child underwent twice weekly 45-minute physical therapy sessions for 48 weeks. The research was carried out between March 2022 and February 2023. The purpose of the intervention, which comprised a variety of therapeutic workouts, was to enhance physical function and gross motor abilities in an age-appropriate manner. The intervention utilized in this study led to improvements in GMFM-88, HFMS, and MMT total scores. The results of this case study showed that a child with type 2 SMA aged nine had successfully improved their gross motor skills and muscle strength.

Correlations between clinical motor scores and CMAP in patients with type 2 spinal muscular amyotrophy treated with nusinersen

BACKGROUND

Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the degeneration of the anterior horn cells of the spinal cord. Nusinersen for the treatment of SMA has been covered by public healthcare in France since May 2017.

OBJECTIVE

Our aim was to investigate whether there is a correlation between clinical and compound motor action potential (CMAP) measurements in SMA patients treated with nusinersen after 3  years' follow-up.

METHOD

Motor skills were evaluated regularly between M0 and M36 using the Motor Function Measure (MFM) score. CMAP measurements were collected regularly between M0 and M22.

RESULTS

Data for 10 patients with SMA type 2 were collected and divided into two age groups (< 5 years and > 5 years). Motor function improved, but not significantly, regarding distal motor skills (D3) in both groups, and in axial and proximal motor function (D2) in the younger group. CMAP measurements improved in all patients. CMAP increased significantly for the median nerve, and this improvement correlated significantly with global MFM and with axial and proximal tone (D2).

CONCLUSION

Our study shows gain in distal motor function with nusinersen, especially in younger patients with SMA type 2. These results encourage the screening of SMA patients and treatment as early as possible. CMAP measurements of the median nerve show clear improvement in patients treated with nusinersen and could be performed as routine follow-up.

Current Advances in Genetic Testing for Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is one of the most common genetic disorders worldwide, and genetic testing plays a key role in its diagnosis and prevention. The last decade has seen a continuous flow of new methods for SMA genetic testing that, along with traditional approaches, have affected clinical practice patterns to some degree. Targeting different application scenarios and selecting the appropriate technique for genetic testing have become priorities for optimizing the clinical pathway for SMA. In this review, we summarize the latest technological innovations in genetic testing for SMA, including MassArray®, digital PCR (dPCR), next-generation sequencing (NGS), and third-generation sequencing (TGS). Implementation recommendations for rationally choosing different technical strategies in the tertiary prevention of SMA are also explored.

Efficacy and safety of salbutamol in treatment of children with later-onset spinal muscular atrophy

OBJECTIVES

To investigate the clinical efficacy and safety of salbutamol in the treatment of children with later-onset spinal muscular atrophy (SMA).

METHODS

This study is a prospective single-arm phase Ⅲ clinical study. Pediatric patients with SMA type Ⅱ and Ⅲ who visited Department of Neurology, Children's Hospital, Zhejiang University School of Medicine from December 2020 to June 2022 were enrolled. All patients were evaluated with motor function scales, pulmonary function test and drug safety before study. Patients were treated with salbutamol tablets orally, with an initial dose of 1 mg (tid). If tolerable, the dose was increased to 1.5 mg (tid) in the second week, then increased to 2 mg (tid) from the third week and maintained for 6 months. Patients were followed up at 1, 3 and 6 months of treatment.

RESULTS

Twenty-six patients were enrolled, including 10 boys and 16 girls. There were 16 cases of SMA type Ⅱ and 10 cases of type Ⅲ with age at treatment initiation of 5.67 (3.13, 7.02) years and disease duration of 2.54 (1.31, 4.71) years. The Hammersmith Functional Motor Scale-Expanded (HFMSE) scores were increased from 14.0 (6.5, 43.0) before treatment to 26.0 (15.0, 46.5) after treatment (Z=－4.144, P<0.01) in 25 cases. The Revised Upper Limb Module Scale scores were increased from 33.0 (25.5, 36.0) before treatment to 35.0 (31.0, 36.5) after treatment (Z=－2.214, P<0.05) in 9 cases. In 7 ambulant children with SMA type Ⅲ, the six minutes walking distance was increased by 30 (15, 52) m after a 6-month treatment (Z=－2.366, P<0.05). Compared with the baseline pulmonary functions the patients showed a significant increase in forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow (PEF) in 15 cases after treatment (all P<0.05). According to patients and caregivers subjective reporting, there were various degrees of improvement in coughing, sputum production ability and exercise endurance. No serious adverse events were observed during the study.

CONCLUSIONS

Short-term oral administration of salbutamol may improve motor and pulmonary functions in later-onset SMA children with good safety.

Neonatal screening for spinal muscular atrophy: A pilot study in Brazil

Spinal muscular atrophy (SMA) is considered one of the most common autosomal recessive disorders, with an estimated incidence of 1 in 10,000 live births. Testing for SMA has been recommended for inclusion in neonatal screening (NBS) panels since there are several therapies available and there is evidence of greater efficacy when introduced in the pre/early symptomatic phases. In Brazil, the National Neonatal Screening Program tests for six diseases, with a new law issued in 2021 stating that it should incorporate more diseases, including SMA. In the present study, dried blood spot (DBS) samples collected by the Reference Services of Neonatal Screening of RS and SP, to perform the conventional test were also screened for SMA, using real-time PCR, with SALSA MC002 technique. A total of 40,000 samples were analyzed, enabling the identification of four positive cases of SMA, that were confirmed by MLPA. Considering our sampling, Brazil seems to have an incidence comparable to the described in other regions. This work demonstrated that the use of the MC002 technique in samples routinely collected for the conventional NBS program is suitable to screen for SMA in our conditions and can be included in the expansion of the neonatal screening programs.

Structured Light Plethysmography for Non-Invasive Assessment of Respiratory Pattern in Spinal Muscular Atrophy Type 1

BACKGROUND

Spinal muscular atrophy (SMA) type 1 is a severe condition leading to early respiratory failure. Treatment options have become available, yet respiratory outcome measures in SMA type 1 are limited. The aim of this study was to assess the respiratory pattern in SMA type 1 patients via structured light plethysmography (SLP). SLP measures the thoraco-abdominal movements by projecting a light grid onto the anterior thoraco-abdominal surface.

METHODS

Cross-sectional study of consecutive children with SMA type 1. All children underwent motor assessment (CHOP-INTEND) and one-minute tidal breathing recording by SLP in supine position while self-ventilating in room air. The Respiratory rate, the abdominal vs. chest contribution to breath (Relative Expired Abdomen%, Relative Expired Chest%) and the severity of thoraco-abdominal paradox (Phase Angle) were acquired.

RESULTS

Nineteen patients were included, median (IQR) age 2.3 years (1.4-7.9). Their respiratory pattern captured via SLP showed a raised median (IQR) respiratory rate per age of 33.5 bpm (26.6-41.7), a prevalent abdominal contribution to tidal breathing with median (IQR) Relative Expired Abdomen 77% (68-90) vs. Chest 23% (10-32). Thoracoabdominal paradox was detected (median Phase Angle 48.70°) and its severity correlated negatively with CHOP-INTEND (r -0.8, p < 0.01).

CONCLUSIONS

SLP captured and quantified the respiratory features of infants and children with SMA type 1.

Nusinersen for Spinal Muscular Atrophy Type I with Chronic Respiratory Failure: A Retrospective Study in South Korea

PURPOSE

To analyze the efficacy and safety of nusinersen in patients with spinal muscular atrophy (SMA) type I with chronic respiratory failure.

MATERIALS AND METHODS

We retrospectively reviewed seven patients diagnosed with SMA type I and chronic respiratory failure who were on permanent ventilation and treated with nusinersen at Gangnam Severance Hospital between January 2018 and July 2023. Patient demographics and clinical characteristics were recorded, and treatment progress was evaluated according to Hammersmith Infant Neurological Examination (HINE-2) and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) scores.

RESULTS

Patients initially developed hypotonia at a mean age of 3.7 months. Mean age at start of nusinersen was 7.3 years; the mean duration of follow-up after starting nusinersen was 46.2 months. At 6-, 18-, 38-, 58-, and 74-month follow-up, the mean changes in CHOP-INTEND scores were 1.0, 2.9, 1.8, 1.5, and 1.5, respectively, and the proportions of patients who showed disease amelioration were 28.6%, 71.4%, 75.0%, 100%, and 100%, respectively.

CONCLUSION

Nusinersen is safe and effective in patients with SMA type I, even those with chronic respiratory failure and those on permanent ventilation. No significant adverse effects of nusinersen were observed.

Role of circulating biomarkers in spinal muscular atrophy: insights from a new treatment era

Spinal muscular atrophy (SMA) is a lower motor neuron disease due to biallelic mutations in the SMN1 gene on chromosome 5. It is characterized by progressive muscle weakness of limbs, bulbar and respiratory muscles. The disease is usually classified in four different phenotypes (1-4) according to age at symptoms onset and maximal motor milestones achieved. Recently, three disease modifying treatments have received approval from the Food and Drug Administration (FDA) and the European Medicines Agency (EMA), while several other innovative drugs are under study. New therapies have been game changing, improving survival and life quality for SMA patients. However, they have also intensified the need for accurate biomarkers to monitor disease progression and treatment efficacy. While clinical and neurophysiological biomarkers are well established and helpful in describing disease progression, there is a great need to develop more robust and sensitive circulating biomarkers, such as proteins, nucleic acids, and other small molecules. Used alone or in combination with clinical biomarkers, they will play a critical role in enhancing patients' stratification for clinical trials and access to approved treatments, as well as in tracking response to therapy, paving the way to the development of individualized therapeutic approaches. In this comprehensive review, we describe the foremost circulating biomarkers of current significance, analyzing existing literature on non-treated and treated patients with a special focus on neurofilaments and circulating miRNA, aiming to identify and examine their role in the follow-up of patients treated with innovative treatments, including gene therapy.

Cognitive impairment in Chinese adult patients with type III spinal muscular atrophy without disease-modifying treatment

Objective

Spinal muscular atrophy (SMA) is a neurodegenerative disorder characterized by the degeneration of motor neurons in the spinal cord. It remains uncertain whether the cognitive performance of adult patients with SMA is impaired. The objective of this study was to assess the cognitive profile of adult Chinese patients with SMA and the association between clinical features and cognitive ability, particularly executive function.

Methods

This cross-sectional study included 22 untreated adult patients with type III SMA and 20 healthy subjects. The following variables were assessed: general intelligence, memory, attention, language, executive function, depression, anxiety, and other demographic and clinical parameters. In addition, physical function was evaluated using the Hammersmith Functional Motor Scale Expanded (HFMSE), the Revised Upper Limb Module (RULM), and the 6-Minute Walk Test (6MWT).

Results

SMA patients had lower scores than healthy subjects in the Verbal Fluency Test, Stroop effect, Total Errors, Perseverative Responses, Perseverative Errors, and Non-perseverative Errors in the Wisconsin Card Sorting Test, showing impaired abilities of SMA patients in executive function. In the Attention Network Test (ANT), the results indicated that the SMA patients also had selective deficits in their executive control networks. Ambulant patients had better executive function test performance than non-ambulant ones. Compromised executive abilities in patients with SMA were correlated with a younger age at onset, poorer motor function, and higher levels of anxiety and depression.

Conclusion

Our study presented the distribution of cognitive impairment in a Chinese cohort with SMA. Patients with type III SMA showed selective deficits in executive function, which may be associated with disease severity, physical impairment, depression and anxiety. Future cognitive studies, accounting for motor and emotional impairment, are needed to evaluate if executive impairment is driven by specific brain changes or by those confounding factors.

Twice-Weekly Outpatient Rehabilitation Intervention for Young Children With Spinal Muscular Atrophy Treated With Genetic-Based Therapies: Protocol for a Feasibility Study

BACKGROUND

Spinal muscular atrophy (SMA) is a progressive neuromuscular disorder that causes muscle weakness and is the leading genetic cause of infant mortality worldwide. While no definitive cure exists, the approval of 3 genetic-based therapies in Canada since 2018 has led to significant improvements in muscle function for children with SMA. With that, there are no evidence-based rehabilitation interventions and minimal evidence on the combined effects of genetic-based therapies and rehabilitation.

OBJECTIVE

This protocol describes the methodology to assess the feasibility of a twice-weekly outpatient rehabilitation intervention focusing on gross and fine motor function to inform the methodology and sample size of a definitive clinical trial.

METHODS

We will conduct a single-center nonrandomized pilot and feasibility trial to explore an outpatient rehabilitation intervention for children aged 6 months to 3 years with SMA treated with genetic-based therapies. Participation in the study will occur over a 25-week period, with a baseline assessment visit followed by a 12-week intervention period and a 12-week nonintervention period. The rehabilitation intervention comprises weekly physical and occupational therapy for 11 weeks. Assessments will occur at baseline (week 0), end of intervention or early withdrawal (week 12), and follow-up (week 24). Predetermined feasibility indicators will evaluate study feasibility across process (recruitment rates, eligibility criteria, adherence rates, retention rates, questionnaire suitability, and acceptability), resource (time, implementation, and execution), management (materials and data), and scientific (safety, tolerability, and preliminary efficacy) domains.

RESULTS

This project was funded in March 2022, and data will be collected between March 2023 and December 2023. Data analysis will occur between January 2024 and March 2024, with publication expected in the fall of 2024. The protocol for the feasibility trial will be considered successful if it meets the success criteria set out for the feasibility indicators. Indicators of specific interest include all process indicators, as well as time. Exploratory indicators will be reported. Pragmatically, the results of the feasibility trial will inform changes to the protocol and the start-up of a definitive multisite trial.

CONCLUSIONS

This novel twice-weekly outpatient rehabilitation intervention will be the first step toward filling the need for an evidence-based rehabilitation intervention for children with SMA treated with genetic-based therapies. It is expected that consistent and intensive rehabilitation therapy will augment functional gains being observed in this population. In the future, a definitive trial will measure the efficacy of the intervention.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05638750; https://clinicaltrials.gov/study/NCT05638750.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/46363.

Significant healthcare burden and life cost of spinal muscular atrophy: real-world data

OBJECTIVES

The aim of this study is to quantify the mortality rate, direct healthcare costs, and cumulative life costs of pediatric patients with spinal muscular atrophy (SMA) type 1, type 2, and type 3 born in Hong Kong.

METHODS

Data were collected from genetically confirmed SMA patients born in or after 2000 from the Hospital Authority medical database. Patients were followed up from birth until they died, left Hong Kong, reached 18 years, or initiated disease-modifying treatment. Study outcomes included incidence risks of mortality, cumulative direct medical costs-attendances of special outpatient clinics, emergency department, allied health services, and mean length of stay in hospitals over time. Total direct medical costs were calculated as unit costs multiplied by utilization frequencies of corresponding healthcare services at each age.

RESULTS

Seventy-one patients with SMA were included. Over a median follow-up period of 6 years, the overall incidence rate of death was 5.422/100 person-years (95%CI 3.542-7.945/100 person-years). 67.7% and 11% of deaths occurred in SMA1 and SMA2 groups, respectively. The median age of death was 0.8 years in SMA1 and 10.9 years in SMA2. The mean cumulative direct medical costs in overall SMA, SMA1, SMA2 and SMA3 groups per patient were US$935,570, US$2,393,250, US$413,165, and US$40,735, respectively.

INTERPRETATION

Our results confirmed a significantly raised mortality and extremely high healthcare burden for patients with SMA especially SMA type 1 and 2 without disease-modifying treatment. Study evaluating health and economic impact of newborn screening and early treatment is needed.

Bone Health Status of Children with Spinal Muscular Atrophy

BACKGROUND

Spinal muscular atrophy (SMA) is a group of rare, inherited neuromuscular disorders. Bone health is often a neglected issue in children with SMA. This study aimed to evaluate the bone health status of children with SMA in Hong Kong.

METHODS

This retrospective study included children with SMA who were managed in the Neuromuscular Disorder Clinics of 2 quaternary centers in Hong Kong. Bone health status was assessed by fracture history, bone mineral density (BMD) measured by dual energy X-ray absorptiometry, and serum 25-hydroxy-vitamin D (25[OH]D) level.

RESULTS

Thirty-two children were included (males, 12). The median age was 10.8 years. BMD assessments were performed in 17 patients (SMA type 1=2, type 2=8, type 3=7). Low BMD was observed in 16 out of 17 patients. Four had a history of long bone fractures and were started on bisphosphonates. SMA types, age at last visit, sex, ambulation, and 25(OH)D level were not associated with fracture history or BMD Z-scores. Only one fulfilled the 2019 International Society for Clinical Densitometry (ISCD) pediatric definition of osteoporosis, with both low BMD and a history of clinically significant fracture.

CONCLUSIONS

Children with SMA on disease-modifying treatments commonly had Low BMD and a history of fractures, but osteoporosis was uncommon according to the 2019 ISCD pediatric definition. A special definition of osteoporosis may be needed for this high-risk group.

Electrophysiological and Imaging Biomarkers to Evaluate Exercise Training in Patients with Neuromuscular Disease: A Systematic Review

Exercise therapy as part of the clinical management of patients with neuromuscular diseases (NMDs) is complicated by the limited insights into its efficacy. There is an urgent need for sensitive and non-invasive quantitative muscle biomarkers to monitor the effects of exercise training. Therefore, the objective of this systematic review was to critically appraise and summarize the current evidence for the sensitivity of quantitative, non-invasive biomarkers, based on imaging and electrophysiological techniques, for measuring the effects of physical exercise training. We identified a wide variety of biomarkers, including imaging techniques, i.e., magnetic resonance imaging (MRI) and ultrasound, surface electromyography (sEMG), magnetic resonance spectroscopy (MRS), and near-infrared spectroscopy (NIRS). Imaging biomarkers, such as muscle maximum area and muscle thickness, and EMG biomarkers, such as compound muscle action potential (CMAP) amplitude, detected significant changes in muscle morphology and neural adaptations following resistance training. MRS and NIRS biomarkers, such as initial phosphocreatine recovery rate (V), mitochondrial capacity (Qmax), adenosine phosphate recovery half-time (ADP t1/2), and micromolar changes in deoxygenated hemoglobin and myoglobin concentrations (Δ[deoxy(Hb + Mb)]), detected significant adaptations in oxidative metabolism after endurance training. We also identified biomarkers whose clinical relevance has not yet been assessed due to lack of sufficient study.

Profile of cognitive abilities in spinal muscular atrophy type II and III: what is the role of motor impairment?

There has recently been some concern on possible cognitive impairment in patients with Spinal Muscular Atrophy (SMA). The aim of this study was to assess cognitive profiles in type II and III SMA with a focus on individual indexes and possible correlations with motor function. 57 type II and III individuals, aged 3.5-17 years, were consecutively enrolled in a prospective, multicentric study. Cognitive function was assessed using age-appropriate Weschler Scales. Motor function was concomitantly assessed using disease-specific functional scales. Only 2 individuals (3%) had a intellectual disability of mild degree while the others were within normal range, with no significant difference in relation to SMA type, gender or functional status. While the overall quotients were mostly within normal range, some indexes showed wider variability. A significant positive medium correlation was found between Processing Speed Index and motor functional scores. Working memory had lower scores in type III patients compared to type II. Intellectual disability is uncommon in type II and III SMA. Motor functional abilities may play a role in some of the items contributing to the overall cognitive profile.