Comprehensive profile and natural history of pediatric patients with spinal muscular atrophy: A large retrospective study from China

Quantitative assessment of muscle atrophy and structural changes in children with spinal muscular atrophy using ultrasound imaging

BACKGROUND

Spinal muscular atrophy (SMA) in children is a hereditary neuromuscular disorder characterized by motor neuron degeneration, which leads to progressive muscle weakness and impaired movement. Ultrasound imaging, owing to its non-invasive, radiation-free, and cost-effective nature, provides an invaluable tool for visualizing muscle morphology. This technique offers a significant advantage in the clinical evaluation of SMA. The aim of this study was to quantitatively assess muscle abnormalities in children with SMA using both conventional ultrasound and shear wave elastography (SWE), and to explore the potential of these imaging modalities in the assessment of the disease.

METHODS

A total of 20 patients with type II or III SMA, who had not received any prior disease-modifying treatment (DMT), were included in the SMA group. These patients were enrolled between May 2022 and January 2024. The control group comprised 20 healthy children matched for age and gender. Muscle thickness (MT) and shear wave velocity (SWV) of the biceps brachii (BB) and quadriceps femoris (QF) were measured using B-mode ultrasound and SWE. Ultrasound parameters were compared between children with SMA and healthy controls. Additionally, motor function in the SMA group was assessed using the Hammersmith Functional Motor Scale Expanded (HFMSE), and the correlation between ultrasound parameters and HFMSE scores was analyzed.

RESULTS

The BB-MT, BB-SWV, QF-MT and QF-SWV in the SMA group, were significantly lower than those in the control group (p = 0.030, 0.000, 0.004, and 0.001, respectively). Correlation analysis revealed a significant positive correlation between QF-MT and QF-SWV in the SMA group and the HFMSE score (r = 0.802, p = 0.000; r = 0.56, p = 0.000, respectively).

CONCLUSIONS

Ultrasound imaging is an effective modality for detecting and quantifying muscle atrophy and structural changes in children with SMA. Moreover, it demonstrates a significant correlation with motor function, providing valuable insights into the clinical assessment of SMA.

Pregnancy and delivery in a woman with spinal muscular atrophy type III

OBJECTIVES

To investigate the perinatal management of a spinal muscular atrophy (SMA) patient during pregnancy.

METHODS

A pregnant woman with SMA type III was admitted to Tianjin Medical University General Hospital for prenatal diagnosis and perinatal care.

RESULTS

The pregnant woman was diagnosed with SMA type III based on clinical observations and genetic tests. The results of amniocentesis indicated that the fetus was a carrier of SMA. An elective cesarean section was arranged at 35+3 weeks. Throughout the follow-up period, the patient's SMA symptoms essentially reverted to their pregestational level without any significant exacerbation.

CONCLUSIONS

Genetically confirmed SMA patients in China remain scarce, and those with SMA who are capable of conceiving are even rarer. It is recommended that Patients with SMA undergo prenatal diagnosis and receive pregnancy check-ups and deliveries at a tertiary care hospital with an interdisciplinary medical team.

Research trends on spinal muscular atrophy from 1995 to 2023: A bibliometric analysis

BACKGROUND

Spinal muscular atrophy (SMA) is a neuromuscular disease characterized by progressive muscle weakness due to motor neuron degeneration. The discovery of the survival motor neuron 1 (SMN1) gene in 1995 revolutionized SMA research, leading to significant therapeutic advancements. This bibliometric analysis aimed to explore global trends in SMA research and therapy, with a particular focus on China.

METHODS

A comprehensive database search identified 4506 relevant publications (3812 articles, 694 reviews) published between 1995 and 2023. Bibliometric tools were used to analyze publication trends, collaborations, and research topics.

RESULTS

SMA research has experienced substantial growth, with the United States leading in publications followed by the United Kingdom and Germany. China has shown increasing engagement in this field. Key research areas include genetic and molecular mechanisms, survival motor neuron gene therapy, antisense oligonucleotides, and muscle strength-promoting factors. Chinese researchers have contributed significantly to these areas, with a higher reporting frequency of SMA-related topics compared to other countries.

CONCLUSION

This bibliometric analysis provides a comprehensive overview of global SMA research, highlighting significant advancements, and identifying future directions. The findings offer valuable insights for researchers, clinicians, and policymakers in China to ensure alignment with global medical advancements and improve the lives of individuals affected by SMA.

Association among biomarkers, phenotypes, and motor milestones in Chinese patients with 5q spinal muscular atrophy types 1-3

Background

Biomarkers can be used to assess the severity of spinal muscular atrophy (5q SMA; SMA). Despite their potential, the relationship between biomarkers and clinical outcomes in SMA remains underexplored. This study aimed to assess the association among biomarkers, phenotypes, and motor milestones in Chinese patients diagnosed with SMA.

Methods

We collected retrospective clinical and follow-up data of disease-modifying therapy (DMT)-naïve patients with SMA at our center from 2019 to 2021. Four biomarkers were included: survival motor neuron 2 (SMN2) copies, neuronal apoptosis inhibitory protein (NAIP) copies, full-length SMN2 (fl-SMN2), and F-actin bundling protein plastin 3 (PLS3) transcript levels. Data were analyzed and stratified according to SMA subtype.

Results

Of the 123 patients, 30 were diagnosed with Type 1 (24.3%), 56 with Type 2 (45.5%), and 37 with Type 3 (30.1%). The mortality rate for Type 1 was 50%, with median survival times of 2 and 8 months for types 1a and 1b, respectively. All four biomarkers were correlated with disease severity. Notably, fl-SMN2 transcript levels increased with SMN2 copies and were higher in Type 2b than those in Type 2a (p = 0.028). Motor milestone deterioration was correlated with SMN2 copies, NAIP copies, and fl-SMN2 levels, while PLS3 levels were correlated with standing and walking function.

Discussion

Our findings suggest that SMN2 copies contribute to survival and that fl-SMN2 may serve as a valuable biomarker for phenotypic variability in SMA Type 2 subtypes. These insights can guide future research and clinical management of SMA.

Rehabilitation for spinal muscular atrophy patients in China: a national cross-sectional study

BACKGROUND

The management of Spinal Muscular Atrophy (SMA) requires a multidisciplinary treatment approach, wherein rehabilitation constitutes an integral element. In this study, we examined the effects of rehabilitation among Chinese SMA patients and assessed the real-world efficacy of rehabilitation interventions.

METHODS

We conducted a cross-sectional online survey on SMA patients from June 9, 2023, to June 30, 2023, through the Meier Advocacy & Support Center using data from the Center's database and electronic questionnaires. The rehabilitation situation of the participants over the past 14 months were investigated. Logistic binary regression was used to analyze the relationship between Pediatric Quality of Life Inventory(PedsQL™) scores and rehabilitation.

RESULT

A total of 186 questionnaires were finally analyzed. Only 29 patients did not rehabilitated in the past 14 months. A significant correlation between age and type of rehabilitation, as well as between age and duration of rehabilitation. Patients receiving no rehabilitation or solely home-based rehabilitation exhibited a higher median age of 8.4 compared to those undergoing standard rehabilitation or a combination of standard and home-based rehabilitation, with a median age of 4.9 (z-score = -4.49, p-value < 0.001). In addition, long-term rehabilitation (OR = 0.314, 95%CI = 0.106-0.927, p = 0.04) were negatively correlated with lower PedsQL™ Neuromuscular Module scores, and PedsQL scores in the long-term rehabilitation group were higher than those in the short-term and no-rehabilitation groups (54.2 ± 15.1 vs. 45.9 ± 14.4 and 42.3 ± 14.3, p = 0.01), with the most significant difference observed in the physical function section (59.0 ± 15.8 vs. 46.8 ± 15.2 and 45.6 ± 15.9, p < 0.01). Mobility and exercise (OR = 0.26, 95%CI = 0.08-0.81, p = 0.02), as well as assistive technology (OR = 0.28, 95%CI = 0.10-0.82, p = 0.02), were independently associated with a lower score in a negative direction.

CONCLUSION

The study found that long-term rehabilitation was linked to higher PedsQL scores in SMA patients, highlighting the need for standardized rehabilitation programs to enhance function and quality of life.

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.