Spinal Muscular Atrophy Treatments, Newborn Screening, and the Creation of a Neurogenetics Urgency

Assessment of Barriers to Referral and Appointment Wait Times for the Evaluation of Spinal Muscular Atrophy (SMA): Findings from a Web-Based Physician Survey

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease characterized by progressive muscle weakness and atrophy. Clinical trial data suggest early diagnosis and treatment are critical. The purpose of this study was to evaluate neurology appointment wait times for newborn screening identified infants, pediatric cases mirroring SMA symptomatology, and cases in which SMA is suspected by the referring physician. Approaches for triaging and expediting referrals in the US were also explored.

METHODS

Cure SMA surveyed healthcare professionals from two cohorts: (1) providers affiliated with SMA care centers and (2) other neurologists, pediatric neurologists, and neuromuscular specialists. Surveys were distributed directly and via Medscape Education, respectively, between July 9, 2020, and August 31, 2020.

RESULTS

Three hundred five total responses were obtained (9% from SMA care centers and 91% from the general recruitment sample). Diagnostic journeys were shorter for infants eventually diagnosed with SMA Type 1 if they were referred to SMA care centers versus general sample practices. Appointment wait times for infants exhibiting "hypotonia and motor delays" were significantly shorter at SMA care centers compared to general recruitment practices (p = 0.004). Furthermore, infants with SMA identified through newborn screening were also more likely to be seen sooner if referred to a SMA care center versus a general recruitment site. Lastly, the majority of both cohorts triaged incoming referrals. The average wait time for infants presenting at SMA care centers with "hypotonia and motor delay" was significantly shorter when initial referrals were triaged using a set of "key emergency words" (p = 0.036).

CONCLUSIONS

Infants directly referred to a SMA care center versus a general sample practice were more likely to experience shorter SMA diagnostic journeys and appointment wait times. Triage guidelines for referrals specific to "hypotonia and motor delay" including use of "key emergency words" may shorten wait times and support early diagnosis and treatment of SMA.

Assisting the implementation of screening for type 1 diabetes by using artificial intelligence on publicly available data

The type 1 diabetes community is coalescing around the benefits and advantages of early screening for disease risk. To be accepted by healthcare providers, regulatory authorities and payers, screening programmes need to show that the testing variables allow accurate risk prediction and that individualised risk-informed monitoring plans are established, as well as operational feasibility, cost-effectiveness and acceptance at population level. Artificial intelligence (AI) has the potential to contribute to solving these issues, starting with the identification and stratification of at-risk individuals. ASSET (AI for Sustainable Prevention of Autoimmunity in the Society; www.asset.healthcare ) is a public/private consortium that was established to contribute to research around screening for type 1 diabetes and particularly to how AI can drive the implementation of a precision medicine approach to disease prevention. ASSET will additionally focus on issues pertaining to operational implementation of screening. The authors of this article, researchers and clinicians active in the field of type 1 diabetes, met in an open forum to independently debate key issues around screening for type 1 diabetes and to advise ASSET. The potential use of AI in the analysis of longitudinal data from observational cohort studies to inform the design of improved, more individualised screening programmes was also discussed. A key issue was whether AI would allow the research community and industry to capitalise on large publicly available data repositories to design screening programmes that allow the early detection of individuals at high risk and enable clinical evaluation of preventive therapies. Overall, AI has the potential to revolutionise type 1 diabetes screening, in particular to help identify individuals who are at increased risk of disease and aid in the design of appropriate follow-up plans. We hope that this initiative will stimulate further research on this very timely topic.

What could be the function of the spinal muscular atrophy-causing protein SMN in macrophages?

Spinal Muscular Atrophy (SMA), a neurodegenerative disorder, extends its impact beyond the nervous system. The central protein implicated in SMA, Survival Motor Neuron (SMN) protein, is ubiquitously expressed and functions in fundamental processes such as alternative splicing, translation, cytoskeletal dynamics and signaling. These processes are relevant for all cellular systems, including cells of the immune system such as macrophages. Macrophages are capable of modulating their splicing, cytoskeleton and expression profile in order to fulfil their role in tissue homeostasis and defense. However, less is known about impairment or dysfunction of macrophages lacking SMN and the subsequent impact on the immune system of SMA patients. We aimed to review the potential overlaps between SMN functions and macrophage mechanisms highlighting the need for future research, as well as the current state of research addressing the role of macrophages in SMA.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Long-Term Follow-Up Cares and Check Initiative: A Program to Advance Long-Term Follow-Up in Newborns Identified with a Disease through Newborn Screening

In the United States and around the world, newborns are screened on a population basis for conditions benefiting from pre-symptomatic diagnosis and treatment. The number of screened conditions continues to expand as novel technologies for screening, diagnosing, treating, and managing disease are discovered. While screening all newborns facilitates early diagnosis and treatment, most screened conditions are treatable but not curable. Patients identified by newborn screening often require lifelong medical management and community support to achieve the best possible outcome. To advance the long-term follow-up of infants identified through newborn screening (NBS), the Long-Term Follow-up Cares and Check Initiative (LTFU-Cares and Check) designed, implemented, and evaluated a system of longitudinal data collection and annual reporting engaging parents, clinical providers, and state NBS programs. The LTFU-Cares and Check focused on newborns identified with spinal muscular atrophy (SMA) through NBS and the longitudinal health information prioritized by parents and families. Pediatric neurologists who care for newborns with SMA entered annual data, and data tracking and visualization tools were delivered to state NBS programs with a participating clinical center. In this publication, we report on the development, use of, and preliminary results from the LTFU-Cares and Check Initiative, which was designed as a comprehensive model of LTFU. We also propose next steps for achieving the goal of a national system of LTFU for individuals with identified conditions by meaningfully engaging public health agencies, clinicians, parents, families, and communities.

The Importance of Early Treatment of Inherited Neuromuscular Conditions

There has been tremendous progress in treatment of neuromuscular diseases over the last 20 years, which has transformed the natural history of these severely debilitating conditions. Although the factors that determine the response to therapy are many and in some instance remain to be fully elucidated, early treatment clearly has a major impact on patient outcomes across a number of inherited neuromuscular conditions. To improve patient care and outcomes, clinicians should be aware of neuromuscular conditions that require prompt treatment initiation. This review describes data that underscore the importance of early treatment of children with inherited neuromuscular conditions with an emphasis on data resulting from newborn screening efforts.

Molecular Mechanisms of Medicinal Plant Securinega suffruticosa-derived Compound Securinine against Spinal Muscular Atrophy based on Network Pharmacology and Experimental Verification

BACKGROUND

Spinal Muscular Atrophy (SMA) is a severe motor neuronal disorder with high morbidity and mortality. Securinine has shown the potential to treat SMA; however, its anti-SMA role remains unclear.

OBJECTIVE

This study aims to reveal the anti-SMA mechanisms of securinine.

METHODS

Securinine-associated targets were acquired from Herbal Ingredients' Targets (HIT), Similarity Ensemble Approach (SEA), and SuperPred. SMA-associated targets were obtained from GeneCards and Dis- GeNET. Protein-protein Interaction (PPI) network was constructed using GeneMANIA, and hug targets were screened using cytoHubba. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using ClusterProfifiler. Molecular docking was conducted using Pymol and Auto- Dock. In vitro assays were used to verify the anti-SMA effects of securinine.

RESULTS

Twenty-six intersection targets of securinine and SMA were obtained. HDAC1, HDAC2, TOP2A, PIK3R1, PRMT5, JAK2, HSP90AB1, TERT, PTGS2, and PAX8 were the core targets in PPI network. GO analysis demonstrated that the intersecting targets were implicated in the regulation of proteins, steroid hormones, histone deacetylases, and DNA transcription. KEGG analysis, pathway-pathway, and hub target-pathway networks revealed that securinine might treat SMA through TNF, JAK-STAT, Ras, and PI3K-Akt pathways. Securinine had a favorable binding affinity with HDAC1, HSP90AB, JAK2, PRMT5, PTGS2, and TERT. Securinine rescued viability suppression, mitochondria damage, and SMN loss in the SMA cell model. Furthermore, securinine increased HDAC1 and PRMT5 expression, decreased PTGS2 expression, suppressed the JAK2-STAT3 pathway, and promoted the PI3K-Akt pathway.

CONCLUSION

Securinine might alleviate SMA by elevating HDAC1 and PRMT5 expression and reducing PTGS2 via JAK2-STAT3 suppression and PI3K-Akt activation.

Genetic Neuromuscular Disorders and Health Services Access, Utilization, and Needs in Zambia

BACKGROUND

Medical and rehabilitative advances increasingly transform management of rare genetic neuromuscular diseases (GNMDs) for children in the global north. Lack of information about GNMDs and related health care needs in sub-Saharan Africa threatens to widen pre-existing health disparities.

METHODS

This is a cross-sectional study of probands enrolling in a study of GNMDs at the University Teaching Hospital in Lusaka, Zambia, a member of the International Consortium for Genomic Medicine in Neuromuscular Disease. Probands/caregivers were interviewed about utilization of medical, rehabilitative, and other support services by a research assistant. A neuromuscular neurologist and/or physiotherapist examined each case and completed an independent questionnaire regarding health service utilization for each proband. Diagnoses were made on available clinical and electrophysiologic data. Molecular findings were unavailable at the time of this analysis.

RESULTS

Among 50 probands, 52% were male with median age 12 (absolute range 2 months to 54 years). Motor neuron diseases (n = 16; 32%), muscle disorders (n = 20; 40%), and inherited polyneuropathies (n = 5; 10%) were most common. Six (15%) cases had insufficient clinical data to classify the GNMDs. Outside of primary care, patient/caregiver-reported access to recommended health services (n = 34; 69%) was challenging. Large disparities in current utilization of health care services versus clinician-recommended services are reported.

CONCLUSIONS

Paradigms to improve access to diagnostics and therapeutic interventions are needed for GNMDs in Zambia. Multidisciplinary clinics may improve access and utilization of needed health services. Qualitative and other research focused on improving referrals, access, and quality of available health services are greatly needed.

Third-generation sequencing for genetic disease

Third-generation sequencing (TGS) has led to a brave new revolution in detecting genetic diseases over the last few years. TGS has been rapidly developed for genetic disease applications owing to its significant advantages such as long read length, rapid detection, and precise detection of complex and rare structural variants. This approach greatly improves the efficiency of disease diagnosis and complements the shortcomings of short-read sequencing. In this paper, we first briefly introduce the working mechanism of one of the most important representatives of TGS, single-molecule real-time (SMRT) sequencing by Pacific Bioscience (PacBio), followed by a review and comparison of the advantages and disadvantages of different sequencing technologies. Finally, we focused on the progress of SMRT sequencing applications in genetic disease detection. Future perspectives on the applications of TGS in other fields were also presented. With the continuous innovation of the SMRT technologies and the expansion of their fields of application, SMRT sequencing has broad clinical application prospects in genetic diseases detection, and is expected to become an important tool for the molecular diagnosis of other diseases.

Spinal Muscular Atrophy: An Evolving Scenario through New Perspectives in Diagnosis and Advances in Therapies

Spinal muscular atrophy (SMA) linked to 5q is a recessive motor neuron disease characterized by progressive and diffuse weakness and muscular atrophy. SMA is the most common neurodegenerative disease in childhood with an incidence of approximately 1 in 6000-10,000 live births, being long considered a leading cause of hereditary mortality in infancy, worldwide. The classification of SMA is based on the natural history of the disease, with a wide clinical spectrum of onset and severity. We are currently in a new therapeutic era, that, thanks to the widespread use of the newly approved disease-modifying therapies and the possibility of an early administration, should lead to a deep change in the clinical scenario and, thus, in the history of SMA. With the aim to achieve a new view of SMA, in this review we consider different aspects of this neuromuscular disease: the historical perspective, the clinical features, the diagnostic process, the psychological outcome, innovation in treatments and therapies, the possibility of an early identification of affected infants in the pre-symptomatic phase through newborn screening programs.

Daily Quantity and Kinematic Characteristics of Leg Movement in a Child With SMA (2 Copies SMN2)

PURPOSE

This case report describes daily leg movement quantity and kinematic characteristics of a child with spinal muscular atrophy (SMA) with 2 copies of SMN2, who was symptomatic at the time of treatment with disease-modifying therapies.

KEY POINTS

Compared with infants with typical development, this child had differing values for leg movement quantity, duration, average acceleration, and peak acceleration measured across full days in the natural environment by wearable sensors. In addition, movement quantity and clinician-rated outcomes increased with age.

CONCLUSIONS

Wearable sensors recorded movement quantity and kinematic characteristics in a treated infant with SMA (2 copies SMN2). These movement parameters were consistently different compared anecdotally with published data from infants with typical development, demonstrating their potential to add unique and complementary information to the assessment of motor function in SMA.

RECOMMENDATIONS

Larger longitudinal studies are needed to determine the utility of wearable sensors as an assessment tool and an early predictor of motor outcomes in children with SMA.

Decision-making and challenges within the evolving treatment algorithm in spinal muscular atrophy: a clinical perspective

INTRODUCTION

The clinical application of disease modifying therapies has dramatically changed the paradigm of the management of people with spinal muscular atrophy (SMA), from sole reliance on symptomatic care directed toward the downstream consequences of muscle weakness, to proactive intervention and even preventative care.

AREAS COVERED

In this perspective, the authors evaluate the contemporary therapeutic landscape of SMA and discuss the evolution of novel phenotypes and the treatment algorithm, including the key factors that define individual treatment choice and treatment response. The benefits achieved by early diagnosis and treatment through newborn screening are highlighted, alongside an appraisal of emerging prognostic methods and classification frameworks to inform clinicians, patients, and families about disease course, manage expectations, and improve care planning. A future perspective of unmet needs and challenges is provided, emphasizing the key role of research.

EXPERT OPINION

SMN-augmenting therapies have improved health outcomes for people with SMA and powered the practice of personalized medicine. Within this new proactive diagnostic and treatment paradigm, new phenotypes and different disease trajectories are emerging. Ongoing collaborative research efforts to understand the biology of SMA and define optimal response are critical to refining future approaches.

Spinal Muscular Atrophy Treatment in Patients Identified by Newborn Screening-A Systematic Review

BACKGROUND

In spinal muscular atrophy, clinical trial results indicated that disease-modifying treatments are highly effective when given prior to symptom onset, which has prompted newborn screening programs in growing number of countries. However, prognosis of those patients cannot be inferred from clinical trials conducted in presymptomatic individuals, as in some cases disease presents very early.

METHODS

we conducted a systematic review of articles published up to January 2023.

RESULTS

Among 35 patients with three SMN2 copies treated before 42 days of age and followed-up for at least 18 months, all but one achieved autonomous ambulation. Of 41 patients with two SMN2 copies, who were non-symptomatic at treatment initiation, all achieved a sitting position independently and 31 were able to walk. Of 16 patients with two SMN2 copies followed-up for at least 18 months who presented with symptoms at treatment onset, 3 achieved the walking milestone and all but one were able to sit without support.

CONCLUSIONS

evaluation of data from 18 publications indicates that the results of early treatment depend on the number of SMN2 copies and the initial neurological status of the patient.

Scaling genetic resources: New paradigms for diagnosis and treatment of rare genetic disease

Development of genetic tests for rare genetic diseases has traditionally focused on individual diseases. Similarly, development of new therapies occurred one disease at a time. With >10,000 rare genetic diseases, this approach is not feasible. Diagnosis of genetic disorders has already transcended old paradigms as whole exome and genome sequencing have allowed expedient interrogation of all relevant genes in a single test. The growth of newborn screening has allowed identification of diseases in presymptomatic babies. Similarly, the ability to develop therapies is rapidly expanding due to technologies that leverage platform technology that address multiple diseases. However, movement from the basic science laboratory to clinical trials is still hampered by a regulatory system rooted in traditional trial design, requiring a fresh assessment of safe ways to obtain approval for new drugs. Ultimately, the number of nucleic acid-based therapies will challenge the ability of clinics focused on rare diseases to deliver them safely with appropriate evaluation and long-term follow-up. This manuscript summarizes discussions arising from a recent National Institutes of Health conference on nucleic acid therapy, with a focus on scaling technologies for diagnosis of rare disorders and provision of therapies across the age and disease spectrum.

Effect of nusinersen on motor, respiratory and bulbar function in early-onset spinal muscular atrophy

5q-associated spinal muscular atrophy is a rare neuromuscular disorder with the leading symptom of a proximal muscle weakness. Three different drugs have been approved by the European Medicines Agency and Food and Drug Administration for the treatment of spinal muscular atrophy patients, however, long-term experience is still scarce. In contrast to clinical trial data with restricted patient populations and short observation periods, we report here real-world evidence on a broad spectrum of patients with early-onset spinal muscular atrophy treated with nusinersen focusing on effects regarding motor milestones, and respiratory and bulbar insufficiency during the first years of treatment. Within the SMArtCARE registry, all patients under treatment with nusinersen who never had the ability to sit independently before the start of treatment were identified for data analysis. The primary outcome of this analysis was the change in motor function evaluated with the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders and motor milestones considering World Health Organization criteria. Further, we evaluated data on the need for ventilator support and tube feeding, and mortality. In total, 143 patients with early-onset spinal muscular atrophy were included in the data analysis with a follow-up period of up to 38 months. We observed major improvements in motor function evaluated with the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders. Improvements were greater in children >2 years of age at start of treatment than in older children. 24.5% of children gained the ability to sit independently. Major improvements were observed during the first 14 months of treatment. The need for intermittent ventilator support and tube feeding increased despite treatment with nusinersen. Our findings confirm the increasing real-world evidence that treatment with nusinersen has a dramatic influence on disease progression and survival in patients with early-onset spinal muscular atrophy. Major improvements in motor function are seen in children younger than 2 years at the start of treatment. Bulbar and respiratory function needs to be closely monitored, as these functions do not improve equivalent to motor function.

Experience of a 2-year spinal muscular atrophy NBS pilot study in Italy: towards specific guidelines and standard operating procedures for the molecular diagnosis

BACKGROUND

Spinal muscular atrophy (SMA) is due to the homozygous absence of SMN1 in around 97% of patients, independent of the severity (classically ranked into types I-III). The high genetic homogeneity, coupled with the excellent results of presymptomatic treatments of patients with each of the three disease-modifying therapies available, makes SMA one of the golden candidates to genetic newborn screening (NBS) (SMA-NBS). The implementation of SMA in NBS national programmes occurring in some countries is an arising new issue that the scientific community has to address. We report here the results of the first Italian SMA-NBS project and provide some proposals for updating the current molecular diagnostic scenario.

METHODS

The screening test was performed by an in-house-developed qPCR assay, amplifying SMN1 and SMN2. Molecular prognosis was assessed on fresh blood samples.

RESULTS

We found 15 patients/90885 newborns (incidence 1:6059) having the following SMN2 genotypes: 1 (one patient), 2 (eight patients), 2+c.859G>C variant (one patient), 3 (three patients), 4 (one patient) or 6 copies (one patient). Six patients (40%) showed signs suggestive of SMA at birth. We also discuss some unusual cases we found.

CONCLUSION

The molecular diagnosis of SMA needs to adapt to the new era of the disease with specific guidelines and standard operating procedures. In detail, SMA diagnosis should be felt as a true medical urgency due to therapeutic implications; SMN2 copy assessment needs to be standardised; commercially available tests need to be improved for higher SMN2 copies determination; and the SMN2 splicing-modifier variants should be routinely tested in SMA-NBS.

Hastening the Diagnosis of Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a chronic progressive neurodegenerative disease. Neurologists generally see patients as requested and as schedules allow. This practice is part of the reason it takes approximately 12 months from onset of new progressive weakness to receive a definitive diagnosis of ALS. It is well recognized that the disease of ALS starts long before symptom onset. In mutant SOD1 transgenic mice, early loss of motor neurons and compensatory morphological changes precede a rapid loss of motor neurons that coincides with symptom onset. In a human autopsy study, anterior roots in the "presymptomatic" stage indicate that ∼20% loss of motor neurons had already occurred. Sera collected from individuals who later developed ALS and sera from presymptomatic members of families with ALS harboring pathogenic gene variants demonstrated high neurofilament (Nf) levels, again suggesting that the neurodegenerative process is already active at a clinically presymptomatic stage. Potential benefits of hastening the diagnosis of ALS include earlier initiation of therapy to slow the fundamental neurodegenerative process. Such effects are observed in treatment with riluzole, edaravone, methylcobalamin, and sodium phenylbutyrate-taurursodiol in patient care and clinical trial settings. Early initiation of multidisciplinary care results in cost savings and prolonged survival. Early diagnosis after symptom onset also seems to reduce psychological distress. Hence, how can we facilitate an earlier diagnosis of ALS? We already have the necessary tools. New and simple ALS diagnostic criteria (Gold Coast Criteria) have been introduced along with genetic testing. At least 2 studies provide Class II evidence that establishes the reliability and sensitivity of CSF and/or serum Nf levels in supporting a diagnosis of ALS. Challenges, however, still exist as to how to facilitate earlier recognition of possible ALS by primary care physicians and other nonneurologist providers and how to foster a sense of urgency among neurologists to accelerate the diagnostic process. In this article, we provide a number of recommendations that we hope will help achieve these ends.