Spinal Muscular Atrophy

Spinal Muscular Atrophy With Severe Hyperlordosis: A Case Report

Spinal muscular atrophy (SMA) indicates a set of inherited autosomal recessive genetic disorders, where, specifically, the anterior horn cell motor neurons in the brain and spinal cord are affected, leading to a severe form of hypotonia and muscle weakness. The incidence is exceptionally rare, commonly manifesting as slowly progressive muscular weakness and atrophy of lower limbs. As per our existing knowledge, this is the first case of SMA associated with hyperlordosis in a patient. Hyperlordosis is a deformity in spinal curvature characterized by an excessive forward spinal curve in the region of the lower back, forming the characteristic C-shape curvature in the lumbar region, just above the buttocks. Parents brought an 11-year-old male child with complaints of inability to get up from a sitting position along with difficulty in walking for the past six months. Upon physical examination, deep tendon reflexes were absent; there was severe hyperlordosis, proximal limb weakness, and notable hypotonia. In our study, we aim to understand the clinical presentation, impact, and association of hyperlordosis in a child diagnosed with SMA. This case report describes the complaints and successful diagnosis of a patient of survivor motor neuron (SMN) gene-related SMA along with severe hyperlordosis backed by evidences of electrophysiology and neuropathology. However, a complete cure and normal lifestyle are not possible due to the lack of affordable and easily accessible therapies.

An observational cohort study on pulmonary function in adult patients with 5q-spinal muscular atrophy under nusinersen therapy

BACKGROUND

Few studies assessed the effect of nusinersen on respiratory function in adult patients with spinal muscular atrophy (SMA). The aim of this single-center study was to analyze pulmonary function and its association with muscle function and quality of life (QoL) in adult patients with 5q-SMA under nusinersen.

METHODS

We recorded forced vital capacity (FVC), forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF) during nusinersen treatment in 38 adult SMA patients. Revised Upper Limb Module (RULM), Hammersmith Functional Motor Scale Expanded (HFMSE), 36-Item Short Form Health Survey (SF-36) questionnaire and Fatigue Severity Scale (FSS) were recorded and correlations between muscle function, QoL, fatigue and respiratory parameters were analyzed.

RESULTS

No differences were detected between mean FVC, FEV1, PEF at different timepoints versus baseline. Ambulatory patients showed significant improvement in mean PEF at month 30, compared to non-ambulatory patients (+ 0.8 ± 0.5 vs. - 0.0 ± 0.5, p < 0.05). Patients with fatigue at baseline showed significant improvement in mean PEF at month 10, compared to patients without fatigue at baseline (+ 0.6 ± 0.9 vs. - 0.4 ± 0.5, p < 0.05). Physical domains of SF-36 positively correlated with the change in FVC and FEV1. FSS negatively correlated with the change in mean PEF.

CONCLUSION

Mean pulmonary function remained stable during nusinersen treatment over a period of up to 30 months. Improvement in pulmonary function was associated with improvement in motor function, fatigue and QoL, early after nusinersen initiation.

Spinal muscular atrophy and anorexia nervosa: a case report

BACKGROUND

Spinal muscular atrophy (SMA) is an autosomal recessive condition affecting lower motor neurons causing progressive muscle atrophy. Anorexia nervosa (AN) is a psychiatric disorder characterised by intense fear of weight gain, restriction of energy intake, and preoccupation with body weight and shape. Low weight, gastrointestinal dysmotility, and respiratory infections are common in SMA but may mask AN. No paediatric cases of AN in SMA have been reported to date.

CASE PRESENTATION

A 14-year-old female with SMA2 presented with 12 months of declining body weight to a nadir of 24.8 kg (BMI 11). This was initially attributed to medical complications including pneumonia and gastroenteritis, and chronic gut dysmotility associated with SMA. Despite almost 2 years of dietetic input and nutritional supplementation due to the weight plateauing from age 11, no significant restoration or gain was achieved. The Eating Disorder Examination-Questionnaire (EDE-Q) indicated a possible eating disorder and psychiatric evaluation confirmed AN. Initial management prioritised close medical monitoring and outpatient weight restoration on an oral meal plan. Skin fold anthropometric measurement was conducted to determine a minimum healthy weight. Individual psychological therapy and family sessions were undertaken. The patient developed major depression and a brief relapse with weight loss to 28 kg. Since then, the patient has maintained a weight of around 35 kg with stable mood.

CONCLUSIONS

Low body weight, feeding issues, gastrointestinal dysmotility, and respiratory infections are common in SMA and diagnostic overshadowing can lead to delayed recognition of anorexia nervosa. Change to growth trajectory and prolonged weight loss should prompt consideration of comorbid psychiatric issues. Screening measures such as the EDE-Q and DASS may be helpful in this population. Close liaison between the neurogenetics and psychiatry teams is helpful. Skin fold anthropometry can assist in identifying a minimum healthy weight range.

A comparative analysis of body composition assessment by BIA and DXA in children with type II and III spinal muscular atrophy

BACKGROUND

Body composition analysis is a valuable tool for assessing and monitoring the nutritional status of children with spinal muscular atrophy (SMA). This study was designed to compare the consistency of bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA), as the gold standard method for assessing body composition in clinical practice when treating children with type II and III SMA.

METHODS

From 2019 to 2021, we performed a retrospective analysis of body composition by DXA and BIA measurement methods in patients with type II and III SMA treated at a Chinese tertiary children's hospital. Fat mass (FM), muscle mass (MM), bone mineral content (BMC), and visceral fat area (VFA) were compared using paired sample t-tests. We calculated Lin's concordance correlation coefficient (CCC) and Spearman correlation coefficient to verify the correlation between DXA and BIA measurements. Bland-Altman analysis was used to assess the consistency of the two methods.

RESULTS

Fifty-seven children with type II and III SMA were recruited. Compared with body composition measured by DXA, the average FM measured by BIA is significantly lower (P <0.001), whereas the average MM, BMC, and VFA measured by BIA are significantly higher (P < 0.001) in children with SMA. Overall, the difference between MM (Delta [BIA-DAX] = 1.6 kg) and FM (Delta [BIA-DAX] = -1.6 kg) measured by DXA and BIA was minor, whereas the difference of VFA (Delta [BIA-DAX] = -43.5 cm) was significantly large. Correlation analysis indicated a substantial correlation of MM (CCC = 0.96 [95% confidence interval (CI) = 0.93-0.98], r = 0.967 [P < 0.0001]) and FM (CCC = 0.95 [95% CI = 0.92-0.97], r = 0.953 [P < 0.0001]), and poor correlation of BMC (CCC = 0.61 [95% CI = 0.42-0.75], r = 0.612 [P < 0.0001]) and VFA (CCC = 0.54 [95% CI = 0.33-0.70], r = 0.689 [P < 0.0001]) measurements between the two methods. The Bland-Altman analysis suggests that the majority of participants were within LOA. In addition, differences in MM and VFA measurements between BIA and DAX increased according to patients' increasing height, whereas differences in FM and BMC did not differ with height.

CONCLUSION

BIA overestimates MM and underestimates the FM, BMC, and VFA in children with SMA compared with DXA measurements. Overall, the non-invasive, easy-to-use, and repeatable BIA measurements were found to be in good agreement with DXA measurements, especially for FM and MM, which are essential parameters for the nutritional evaluation of children with SMA.

Treatment preference among patients with spinal muscular atrophy (SMA): a discrete choice experiment

Objective

To examine patient/caregiver preference for key attributes of treatments for spinal muscular atrophy (SMA).

Background

In the rapidly evolving SMA treatment landscape, it is critically important to understand how attributes of potential treatments may impact patient/caregiver choices.

Design/methods

A discrete choice experiment survey was developed based on qualitative interviews. Patients with SMA (≥ 18 years) and caregivers of patients were recruited through a U.S. patient organization. Respondents made choices in each of 12 sets of hypothetical treatments. The relative importance of five treatment characteristics was compared (measured by regression coefficients [RC] of conditional logit models): (1) improvement or stabilization of motor function, (2) improvement or stabilization of breathing function, (3) indication for all ages or pediatric patients only, (4) route of administration [repeated intrathecal (IT) injections, one-time intravenous (IV) infusion, daily oral delivery] and (5) potential harm (mild, moderate, serious/life threatening).

Results

Patient ages ranged from less than 1 to 67 years (n = 101, 65 self-reported and 36 caregiver-reported) and 64 were female. Total SMA subtypes included: type 1 (n = 21), type 2 (n = 48), type 3 (n = 29), other (n = 3). Prior spinal surgery was reported in 47 patients. Nusinersen and onasemnogene abeparvovec-xioi use were reported in 59 and 10 patients, respectively. Improvement in motor and breathing function was highly valued [RC: 0.65, 95% confidence interval (CI): 0.47–0.83 and RC: 0.79, 95% CI: 0.60–0.98, respectively]. Oral medication and one-time infusion were strongly preferred over repeated IT injections (RC: 0.80, 95% CI: 0.60–0.98 and RC: 0.51, 95% CI: 0.30–0.73, respectively). Patients least preferred an age-restricted label/approved use (≤ 2 years of age) (RC: − 1.28, 95% CI: − 1.47 to − 1.09). Cross-attributes trade-off decision suggested a lower willingness for a high-risk therapy despite additional efficacy gain. For some patients, there may be willingness to trade off additional gains in efficacy for a change in route of administration from repeated intrathecal administration to oral medication.

Conclusions

Improvements in motor/breathing function, broad indication, oral or one-time infusion, and minimal risk were preferred treatment attributes. Treatment decisions should be made in clinical context and be tailored to patient needs.