Sleep disordered breathing in infants identified through newborn screening with spinal muscular atrophy

Pediatric Sleep Quality and Parental Stress in Neuromuscular Disorders: Descriptive Analytical Study

Background

Neuromuscular disorders (NMDs) constitute a heterogeneous group of disorders that affect motor neurons, neuromuscular junctions, and muscle fibers, resulting in symptoms such as muscle weakness, fatigue, and reduced mobility. These conditions significantly affect patients' quality of life and impose a substantial burden on caregivers. Spinal muscular atrophy (SMA) is a relatively common NMD in children that presents in various types with varying degrees of severity.

Objective

This study aimed to evaluate the sleep quality of children with NMDs, particularly SMA types 1, 2, and 3 and assess the stress levels experienced by their parents.

Methods

A descriptive analytical study was conducted from February to October 2023, in selected hospitals and dystrophy associations in Tehran and Isfahan, Iran. A total of 207 children aged 1-14 years with various NMDs were included in the study. Data were collected using a web-based questionnaire with 3 parts: demographic information, the Children's Sleep Habits Questionnaire to assess children's sleep, and the Stress Response Inventory to measure parental stress. Statistical analyses were performed using SPSS version 22, with an α level of .05.

Results

Significant differences in sleep quality were found among SMA types, with mean scores of 74.76 (SD 7.48) for SMA type 1, 76.4 (SD 7.29) for SMA type 2, 72.88 (SD 6.73) for SMA type 3, and 75.87 (SD 5.74) for other NMDs (P=.02). A correlation was found between sleep and length of hospital stay (r=0.234, P<.001)and between sleep and the child's sex (r=-0.140, P=.04). Parental stress scores averaged 95.73 (SD 32.12). There was not a statistically significant difference in parental stress scores among the 4 groups (P=.78). This suggests that parental stress levels were similar across different NMD groups.

Conclusions

Sleep disorders are prevalent among children with NMDs, especially SMA. Parents experience high levels of stress that can affect the care they provide. Therefore, interventions to improve children's sleep and address parental stress are crucial. Regular screening, counseling, and tailored support are recommended to enhance the well-being of children with NMDs and their families.

Respiratory outcomes of onasemnogene abeparvovec treatment for spinal muscular atrophy: national real-world cohort study

Onasemnogene abeparvovec (OA) is a novel gene replacement therapy for patients with spinal muscular atrophy (SMA). This study provides real-world respiratory data for pediatric SMA patients receiving OA who were assessed before and one year after treatment in a multicenter cohort study conducted from 2019 to 2021. Twenty-five OA-treated SMA patients (23 with type 1 and 2 with type 2; median age at treatment 6.1 months, with a range of 0.36-23 months) were included. Sixteen were treatment-naïve, and nine had received various prior treatments. Two patients died due to respiratory failure during the study period. Of the remaining 23 patients, four were put on non-invasive ventilation (NIV), bringing ventilated patients to a total of ten during the post-treatment year. Three patients required permanent NIV support, while 13 did not require any respiratory support. Ventilation time decreased from 14.3 to 11.1 hours per day, and respiratory hospitalizations decreased by 26% (from 0.76 to 0.57 per life year). Fifteen of the 23 patients maintained full oral nutrition at study closure compared to 20 of the 25 at study initiation. This real-world data analysis demonstrates that OA may improve respiratory outcomes in SMA patients. Importantly, compounding factors, such as age at treatment initiation, treatment combinations, and natural history, may influence the respiratory course, thus highlighting the need for standardized long-term management. What is Known: • Respiratory failure is a leading cause of mortality in untreated spinal muscular atrophy type 1 patients. • Onasemnogene abeparvovec (OA) improves neurological outcomes, but real-world respiratory data are limited. What is New: • Our real-world analysis suggests OA may improve respiratory outcomes. • Age at treatment and treatment combinations may also influence respiratory trajectory.

A systematic review of immunosuppressive protocols used in AAV gene therapy for monogenic disorders

The emergence of adeno-associated virus (AAV)-based gene therapy has brought hope to patients with severe monogenic disorders. However, immune responses to AAV vectors and transgene products present challenges that require effective immunosuppressive strategies. This systematic review focuses on the immunosuppressive protocols used in 38 clinical trials and 35 real-world studies, considering a range of monogenic diseases, AAV serotypes, and administration routes. The review underscores the need for a deeper understanding of immunosuppressive regimens to enhance the safety and effectiveness of AAV-based gene therapy. Characterizing the immunological responses associated with various gene therapy treatments is crucial for optimizing treatment protocols and ensuring the safety and efficacy of forthcoming gene therapy interventions. Further research and understanding of the impact of immunosuppression on disease, therapy, and route of administration will contribute to the development of more effective and safer gene therapy approaches in the future.

Postnatal management of preterm infants with spinal muscular atrophy: experience from German newborn screening

BACKGROUND

The introduction of newborn screening (NBS) for spinal muscular atrophy (SMA) has increased the early diagnosis of 5q-associated SMA in presymptomatic and symptomatic preterm infants. National and international recommendations for treating preterms and newborns < 38 weeks of gestational age are unavailable. Our retrospective multicentre study aimed to evaluate the postnatal clinical course of preterm infants with 5q-associated SMA diagnosed since the implementation of NBS in Germany in 2021 and to summarize the German experience regarding the decision-making process for available treatment regimens for preterm infants with ≤ 3 survival of motor neuron 2 (SMN2) copies.

RESULTS

Twelve preterm infants with 5q-associated SMA and a mean gestational age of 34.0 weeks (range: 26.1-36.8) and birth weight of 2022 g (range: 645-3370) were reported from 8/20 German SMA NBS follow-up centers using a pseudonymized questionnaire. Confirmatory diagnosis, including SMN2 copy number, was completed on average on postnatal day 13. All patients had a biallelic deletion of exon 7 or exons 7 and 8 of the survival of motor neuron 1 (SMN1) gene, with SMN2 copy numbers of two in 10 patients and three in two patients. The neonatal course was complicated by respiratory distress due to prematurity (n = 2), sepsis (n = 2), and jaundice (n = 2). At birth, 11 preterm infants (91.6%) were presymptomatic. However, the neurological status of one patient deteriorated at five weeks of age (postconceptional age of 41.8 weeks) prior to the start of treatment. Disease-modifying treatments were initiated in all patients at a mean postconceptional age of 38.8 weeks, with the majority receiving onasemnogene abeparvovec (83.3%, including 2 patients with prior risdiplam bridge therapy). Notably, consensus among participating experts from German neuromuscular centers resulted in 83.3% of patients receiving disease-modifying treatment at term.

CONCLUSIONS

Premature infants with SMA require interdisciplinary care in close collaboration with the neuromuscular center. SMA NBS facilitates early initiation of disease-modifying therapy, ideally during the presymptomatic phase, which significantly influences the prognosis of the newborn.

Impact of Disease-modifying Therapies on Respiratory Function in People with Neuromuscular Disorders

Spinal muscular atrophy (SMA) and Duchenne muscular dystrophy (DMD) are neuromuscular disorders that affect muscular function. The most common causes of morbidity and mortality are respiratory complications, including restrictive lung disease, ineffective cough, and sleep-disordered breathing. The paradigm of care is changing as new disease-modifying therapies are altering disease trajectory, outcomes, expectations, as well as patient and caregiver experiences. This article provides an overview on therapeutic advances for SMA and DMD in the last 10 years, with a focus on the effects of disease-modifying therapies on respiratory function.

Polysomnography findings and respiratory muscle function in infants with early onset spinal muscular atrophy after gene replacement as monotherapy: A prospective study

BACKGROUND

Gene replacement therapy (onasemnogene abeparvovec) is associated with an improvement of the prognosis of children with spinal muscular atrophy, but information on long-term respiratory outcome is scarce. The aim of this study was to report the polysomnography findings and respiratory muscle function of infants with treatment-naive spinal muscular atrophy type 1 and 2 up to 24 months after onasemnogene abeparvovec monotherapy.

METHODS

A clinical and motor evaluation, respiratory muscle function testing, and polysomnography were performed repeatedly.

RESULTS

Fifteen spinal muscular atrophy patients (1 presymptomatic, 7 type 1b, 6 type 1c, and 1 type 2) were included at a median age of 8.6 months (range 3.8-12.6) and followed for 24 months. The thoracic over head circumference ratio was close to normal at baseline (median 1.00 (range 0.90-1.05)) and increased significantly over time. All polysomnography and nocturnal gas exchange parameters were within normal ranges at baseline (median apnea-hypopnea index 2.5 events/hour (range 0.4-5.3)) and follow-up. The inspiratory muscle strength was normal at baseline but tended to slightly decrease over time and the expiratory muscle strength was low at any time especially for patients with recurrent respiratory infections (median (range) at baseline in cmH2O: crying esophageal pressure 54 (30-110), crying transdiaphragmatic pressure 65 (35-107), gastric pressure during maximal cough 26 (10-130), esophageal pressure during maximal cough 61 (38-150)). Only 3 patients required noninvasive ventilation.

CONCLUSION

A continuous respiratory monitoring of spinal muscular atrophy patients during the first years of life following onasemnogene abeparvovec monotherapy seems recommended despite the normality of polysomnography parameters.

ATS core curriculum 2023. Pediatric pulmonary medicine: Respiratory disorders in infants

The American Thoracic Society Core Curriculum updates clinicians annually in pediatric pulmonary disease. This is a summary of the Pediatric Pulmonary Medicine Core Curriculum presented at the 2023 American Thoracic Society International Conference. The respiratory disorders of infancy discussed in this year's review include: the care of the patient with bronchopulmonary dysplasia in the neonatal intensive care unit, clinical phenotypes and comorbidities; diffuse lung disease; pulmonary hypertension; central and obstructive sleep apnea. The care of infants with respiratory disorders often poses significant challenges to the general pediatric pulmonologist, sleep clinician, and neonatologist. This review aims to highlight the most clinically relevant aspects of the evaluation, management, and outcomes of infants with these key respiratory disorders, while emphasizing the importance of multidisciplinary care. Furthermore, this document summarizes essential aspects of genetic testing, novel imaging and treatment modalities, and includes multiple resources for clinical practice.

Invasive versus non-invasive paediatric home mechanical ventilation: review of the international evolution over the past 24 years

BACKGROUND

Home mechanical ventilation (HMV) is the treatment for chronic hypercapnic alveolar hypoventilation. The proportion and evolution of paediatric invasive (IMV) and non-invasive (NIV) HMV across the world is unknown, as well as the disorders and age of children using HMV.

METHODS

Search of Medline/PubMed for publications of paediatric surveys on HMV from 2000 to 2023.

RESULTS

Data from 32 international reports, representing 8815 children (59% boys) using HMV, were analysed. A substantial number of children had neuromuscular disorders (NMD; 37%), followed by cardiorespiratory (Cardio-Resp; 16%), central nervous system (CNS; 16%), upper airway (UA; 13%), other disorders (Others; 10%), central hypoventilation (4%), thoracic (3%) and genetic/congenital disorders (Gen/Cong; 1%). Mean age±SD (range) at HMV initiation was 6.7±3.7 (0.5-14.7) years. Age distribution was bimodal, with two peaks around 1-2 and 14-15 years. The number and proportion of children using NIV was significantly greater than that of children using IMV (n=6362 vs 2453, p=0.03; 72% vs 28%, p=0.048), with wide variations among countries, studies and disorders. NIV was used preferentially in the preponderance of children affected by UA, Gen/Cong, Thoracic, NMD and Cardio-Resp disorders. Children with NMD still receiving primary invasive HMV were mainly type I spinal muscular atrophy (SMA). Mean age±SD at initiation of IMV and NIV was 3.3±3.3 and 8.2±4.4 years (p<0.01), respectively. The rate of children receiving additional daytime HMV was higher with IMV as compared with NIV (69% vs 10%, p<0.001). The evolution of paediatric HMV over the last two decades consists of a growing number of children using HMV, in parallel to an increasing use of NIV in recent years (2020-2023). There is no clear trend in the profile of children over time (age at HMV). However, an increasing number of patients requiring HMV were observed in the Gen/Cong, CNS and Others groups. Finally, the estimated prevalence of paediatric HMV was calculated at 7.4/100 000 children.

CONCLUSIONS

Patients with NMD represent the largest group of children using HMV. NIV is increasingly favoured in recent years, but IMV is still a prevalent intervention in young children, particularly in countries indicating less experience with NIV.

Vaccination proposal for patients on onasemnogene abeparvovec therapy

The approval of disease-modifying treatment in spinal muscular atrophy made the condition less severe. The course of the disease changed, but some new concerns occurred with the different new therapies. The side effects of onasemnogene aboparvovec therapy can raise differential diagnostic challenges and necessitate immune therapy, leading to immunosuppression affecting response to vaccines. We provide a pretherapy screening proposal from an infectological point of view separately for newborns treated presymptomatically and children diagnosed with symptoms at any age. Furthermore, we summarise the guidelines on the vaccination before, during, and after immune therapy (steroids) in onasemnogene aboparvovec-treated patients.