Comprehensive nutritional and metabolic assessment in patients with spinal muscular atrophy: Opportunity for an individualized approach

Nutrition support in children with medical complexity and chronic critical illness: A narrative review

Children with medical complexity (CMC) and children with chronic critical illness (CCI) represent growing populations with high healthcare use and dependence on specialized care, both in the hospital and community setting. Nutrition assessment and delivery represent critical components of addressing the short-term and long-term health needs for these populations across the care continuum. This article provides a framework and reviews existing literature for the assessment of nutrition status and subsequent delivery of nutrition prescriptions in CMC and children with CCI. The specific aims are to (1) describe the epidemiology of health services experience for CMC and children with CCI, with a focus on their nutrition outcomes; (2) detail how to assess their nutrition status and energy requirements; (3) review methods of delivery of the nutrient prescription; (4) introduce perioperative considerations; (5) highlight examples of special populations of CMC and children with CCI; and (6) propose future research initiatives to improve nutrition and overall outcomes for these populations.

A Prospective Study on the Feasibility and Effect of an Optimized Perioperative Care Protocol in Pediatric Neuromuscular Scoliosis Surgery

Background/Objectives: A recent retrospective study conducted by our team identified a high percentage of postoperative pneumonia in children with neuromuscular scoliosis. Based on the findings in that study and our clinical experience, we aimed to assess the effectiveness of an optimized perioperative care protocol. Methods: As part of a prospective study, a multidisciplinary team developed a protocol that included preoperative nutritional and respiratory optimization, intra- and postoperative intravenous glucose infusion, early extubation, and postoperative nutritional optimization. Non-ambulant children between 6 and 18 years of age with neuromuscular scoliosis were eligible for inclusion in the study. The primary outcome was the rate of postoperative pneumonia within 30 days of surgery. The secondary outcome measures were the rate of postoperative complications, including readmissions. All the outcomes were compared to a retrospective control group that was receiving standard care during the same period. Results: Eleven children were included in the intervention group and 14 in the control group. In regard to the intervention group, the nutritional and respiratory assessment before surgery resulted in optimized treatment in 8/11 patients (73%) and 9/11 patients (82%), respectively. One patient (9%) in the intervention group and three patients (21%) in the control group developed postoperative pneumonia (relative risk 0.42, 95% confidence interval 0.05-3.50). The intervention and control groups did not differ significantly in terms of postoperative complications or readmission rates. Conclusions: The multidisciplinary care protocol is feasible, with a high compliance rate in regard to study procedures. A numerical reduction in the 30-day pneumonia rate did occur in the intervention group; however, this reduction did not reach statistical significance.

The endocrine manifestations of adults with spinal muscular atrophy

INTRODUCTION/AIMS

Changes in body composition in patients with spinal muscular atrophy (SMA) can cause endocrine abnormalities that are insufficiently studied in adults. We aimed to assess the endocrine profile in a cohort of adults with SMA. Second, we compared body composition and endocrine profiles between nonambulatory and ambulatory patients and between different types of SMA.

METHODS

The cross-sectional study included 29 SMA patients (18 [62.1%] males and 11 [37.9%] females) of median age 44 (IQR 30-51.5) years with type 2, 3, or 4. Body composition was measured by bioimpedance. Morning blood samples were drawn for glycated hemoglobin (HbA1c), lipid profile, testosterone, cortisol, and insulin-like growth factor-1 (IGF-1). Blood glucose, insulin, and beta-hydroxybutyrate (BHB) were measured during a 75 g oral glucose tolerance test. The homeostatic model assessment for insulin resistance index was calculated.

RESULTS

In total, 75.9% of patients had increased fat mass (FM), with 51.7% having an increase despite normal body mass index. Ambulation was the most important discriminating factor of body composition. 93.1% of patients had metabolic abnormalities, including hyperglycemia, insulin resistance, and dyslipidemia. Increased BHB, a marker of ketosis, was present in more than a third of patients. Functional hypogonadism was present in half of male patients. Testosterone and IGF-1 negatively correlated with FM.

DISCUSSION

Adult patients with SMA had abnormal body composition and highly prevalent metabolic disturbances that might increase cardiometabolic risk. Because treatments have modified the course of SMA, it is important to investigate whether these observations translate into clinically relevant outcomes.

Glucose and Lipid Metabolism Disorders in Adults with Spinal Muscular Atrophy Type 3

BACKGROUND

Spinal muscular atrophy type 3 (juvenile SMA, Kugelberg-Welander disease) is a genetic disease caused by changes in the survival motor neuron 1 (SMN) gene. However, there is increasing evidence of metabolic abnormalities in SMA patients, such as altered fatty acid metabolism, impaired glucose tolerance, and defects in the functioning of muscle mitochondria. Given that data in the literature are scarce regarding this subject, the purpose of this study was to estimate the prevalence of glucose and lipid metabolism disorders in adult patients with SMA type 3.

METHODS

We conducted a cross-sectional study of 23 adult patients with SMA type 3 who underwent a comprehensive evaluation, including a physical examination, biochemical analysis, and an oral glucose tolerance test during 2020-2023.

RESULTS

At least one lipid abnormality was observed in 60.8% of patients. All four lipid parameters were atypical in 4.3% of patients, three lipid parameters were abnormal in 21.7% of patients, and two lipid parameters were altered in 8.7% patients. A total of 91.3% of SMA3 patients met the HOMA-IR criteria for insulin resistance, with 30.43% having impaired glucose tolerance. None of the patients met the criteria for a diagnosis of overt DM2.

CONCLUSIONS

The prevalence of dyslipidemia and altered glucose metabolism in our study sets apart the adult population with SMA3 from the general population, confirming a significant interplay between muscle, liver, and adipose tissue. Ensuring metabolic care for aging patients with SMA 3 is crucial, as they are vulnerable to metabolic derangements and cardiovascular risks.

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.

Metabolic assessment in children with neuromuscular disorders shows risk of liver enlargement, steatosis and fibrosis

AIM

The aim of this study was to conduct a metabolic and nutritional assessment of children with neuromuscular disorders, including the investigation of the liver and bone mineral density.

METHODS

In this observational study, we included 44 children with neuromuscular disorders. The nutritional status, bone health and liver were assessed by ultrasound, transient elastography, dual X-ray absorptiometry scan, blood samples, anthropometric measurements and 3-day diet registration.

RESULTS

Liver involvement was found in 31.0%: liver enlargement in 7.1%, steatosis in 4.8%, fibrosis in 14.3% and liver enlargement together with steatosis or fibrosis was found in 4.8%. These changes were found in 9/23 patients with Duchenne muscular dystrophy, 4/9 patients with spinal muscular atrophy type II and 0/12 patients with other neuromuscular diagnoses. Low bone mineral density was found in 44.0% of the patients, though the majority used daily vitamin D and calcium supplements. Vitamin D insufficiency or deficiency was found in 22.6%.

CONCLUSION

The metabolic assessment in children with neuromuscular disorders shows an increased risk of liver enlargement, steatosis and fibrosis. Possible causes are obesity, decreased mobility, low skeletal muscle mass and for a subgroup the use of glucocorticoids. The findings suggest that monitoring liver function should be part of the nutritional assessment in patients with neuromuscular disorders.

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.

Assessment of body composition, metabolism, and pulmonary function in patients with myotonic dystrophy type 1

Abnormal body composition in myotonic dystrophy type 1 (DM1) are affected by energy intake above resting energy expenditure (REE). We aim to investigate the characteristics and relationship between body composition, REE, and pulmonary function in patients with DM1, and to examine their changes in 1 year. The study design was a single-center, cross-sectional, and longitudinal study of body composition, REE characteristics, and pulmonary function. Twenty-one male patients with DM1 and 16 healthy volunteers were registered in the study. Body composition was measured using dual-energy X-ray absorptiometry (DEXA). Fat mass (FM) index (kg/m2), fat-FM index (kg/m2), and skeletal mass index (kg/m2) were calculated. The measurements were taken breath by breath with a portable indirect calorimeter. The REE was calculated using the oxygen intake (VO2) and carbon dioxide output (VCO2) in the Weir equation. Basal energy expenditure (BEE) was calculated by substituting height, weight, and age into the Harris-Benedict equation. The study enrolled male patients with DM1 (n = 12) and healthy male volunteers (n = 16). Patients with DM1 (n = 7) and healthy volunteers (n = 14) could be followed in 1 year. The body composition of patients with DM1 was significantly higher in the FM index and significantly lower in the fat-FM index and skeletal mass index. The REE of patients with DM1 was significantly lower and was not associated with body composition. Patients with DM1 had poor metabolism that was not related to body composition. FM was high and lean body mass was low.

Association between serum zinc level and lipid profiles in children with spinal muscular atrophy

Background and aims

Children with spinal muscular atrophy (SMA) have a high rate of dyslipidaemia, which is a risk factor of vital importance for cardiovascular diseases in adulthood. Studies have demonstrated that the serum zinc level is associated with lipid profiles in the general population as well as in individuals diagnosed with obesity or diabetes. The purpose of this study was to evaluate the relationship between serum zinc level and lipid profiles in children with SMA.

Methods

This cross-sectional study was launched in a tertiary children's medical center in China and involved pediatric patients with SMA under the management of a multidisciplinary team of outpatient services from July 2019 to July 2021. Anthropometric information, general clinical data, serum zinc level, lipid profiles, and body composition data were collected. Multivariate analysis was used for a thorough inquiry on the association between the serum zinc level and lipid profiles.

Results

Among the 112 patients with SMA [median (IQR) age 5.54 years (2.75–8.29), 58.04% female], who fulfilled the inclusion criteria of the study, dyslipidaemia was detected in 60 patients (53.57%). Based on multivariable linear regression, serum zinc level was positively associated with high-density lipoprotein cholesterol (HDL-C; β = 1.63, 95% CI = 0.44–3.22) and apolipoprotein A1 (APO A1; β = 2.94, 95% CI = 0.03–5.85) levels, independently of age, sex, type, activity, percentage of body fat, and body mass index. As the serum zinc level increased by 10 μmol/L, the risk of low APO A1 levels decreased by 35% (OR = 0.65, 95% CI = 0.44–0.97) according to multivariable logistic regression analyses.

Conclusion

Serum zinc concentration was positively correlated with HDL-C and APO A1 levels among children with SMA. We suggest measures to correct the lower level of serum zinc to improve HDL-C and APO A1 levels.

Prolonged fasting-induced hyperketosis, hypoglycaemia and impaired fat oxidation in child and adult patients with spinal muscular atrophy type II

AIM

This study explored hypoglycaemia and metabolic crises, including hyperketosis, in patients with spinal muscular atrophy (SMA).

METHODS

The study comprised four adolescents aged 15-17 and six adults aged 19-37 with SMA type II and eight adult controls aged 21-41, who were recruited by the Rigshospitalet, Denmark, from May 1st to October 30th 2017. We used stable isotope technique and indirect calorimetry to investigate fat and glucose metabolism during a 24-h fast or until hypoglycaemia occurred.

RESULTS

All patients with SMA II developed moderate to severe hyperketosis and 60% had symptoms of hypoglycaemia or blood glucose levels below 3 mmol/L. None of the controls developed hyperketosis or hypoglycaemia. Plasma bicarbonate decreased, in line with increased ketone bodies, indicating the start of metabolic acidosis in patients with SMA II. Increased fat production and utilisation were seen in healthy controls during the fasting period, but were absent in patients with SMA II, indicating blunted fat oxidation.

CONCLUSION

Low skeletal muscle mass was the best explanation for why patients with SMA II had an increased risk of hypoglycaemia, hyperketosis, metabolic acidosis and disturbed fat and glucose metabolism during fasting. These risks have implications for children facing surgery and those with severe illnesses.

Association Between Body Mass Index and Disability in Children With Charcot-Marie-Tooth Disease

BACKGROUND AND OBJECTIVES

This study examined the association between body mass index (BMI) and disability in children with Charcot-Marie-Tooth disease (CMT).

METHODS

We conducted a cross-sectional analysis of 477 patients with CMT who were 3 to 20 years of age from the Inherited Neuropathy Consortium and 316 age- and sex-matched healthy children from the 1,000 Norms Project. BMI was categorized according to the International Obesity Task Force (IOTF) criteria, and BMI categorization was compared with healthy children. IOTF categories (adult equivalent BMI cut points) were severely underweight (BMI <17 kg/m2), underweight (BMI ≥17-<18.5 kg/m2), healthy weight (BMI ≥18.5-<25 kg/m2), overweight (BMI ≥25-<30 kg/m2), and obese (BMI ≥30 kg/m2). Scores on the 0 to 44-point CMT Pediatric Scale (CMTPedS), a well-validated measure of disability, were examined in relation to BMI.

RESULTS

There was a higher proportion of children with CMT categorized as severely underweight (5.7% vs 0.3%), underweight (10.3% vs 5.1%), and obese (7.3% vs 3.8%) (p < 0.05). Fewer children with CMT were categorized as healthy weight (61.8% vs 74.4%) (p < 0.05), and the proportion of overweight (14.9% vs 16.5%) between groups was similar. CMTPedS scores (mean ± SD) for weight categories were as follows: severely underweight 27 ± 9, underweight 20 ± 8, healthy weight 17 ± 9, overweight 17 ± 9, and obese 22 ± 10. Compared to children with a healthy weight with CMT, being severely underweight was associated with being more disabled (p < 0.001), as was being obese (p = 0.015).

DISCUSSION

The proportion of children with CMT who are underweight or obese is higher compared to age- and sex-matched healthy children. In children with CMT, being underweight or obese is associated with greater disability, when compared to children with CMT of healthy weight.

Nutritional Therapy in Children With Spinal Muscular Atrophy in the Era of Nusinersen

OBJECTIVES

Spinal muscular atrophy (SMA) is a genetic motor neuron disorder characterized by progressive muscle atrophy. Our aims were to evaluate the impact of nutritional intervention and nusinersen therapy on the nutritional status of SMA patients.

STUDY DESIGN

This prospective study included all children and young adults (<24 years of age) with SMA who attended our multidisciplinary SMA clinic, during January 2017-July 2019. We documented demographic, clinical, anthropometric, and nutritional data at baseline and follow-up. A nutritional intervention was implemented according to standards of the 2018 Consensus Statement of SMA Management.

RESULTS

The cohort included 51 SMA patients with a median age of 7.2 (interquartile range 2.1-15.3) years. Among them, 24 (47%) were SMA type 1, 16 (31.4%) SMA type 2, and 11 (21.6%) SMA type 3 patients. At baseline, 28 (54.9%) patients presented with malnutrition, 20 (71.4%) of whom with severe malnutrition. A decline in the frequency of severe malnutrition of SMA type 1 patients was observed at follow-up. The body mass index of patients who started nusinersen therapy after the nutritional intervention increased significantly compared with patients that started nusinersen therapy before the nutritional intervention (P = 0.042). There was also a significant increase in total energy and protein consumption in the former group (P = 0.043).

CONCLUSIONS

Malnutrition is frequent among children with SMA, and the nutritional status of patients that started nusinersen therapy after implementation of a nutritional intervention underwent a more significant improvement. The importance of combining adequate nutritional management with disease-modifying treatment is highlighted.

Predictive fat mass equations for spinal muscular atrophy type I children: Development and internal validation

BACKGROUND

Body composition assessment is paramount for spinal muscular atrophy type I (SMA I) patients, as weight and BMI have proven to be misleading for these patients. Despite its importance, no disease-specific field method is currently available, and the assessment of body composition of SMA I patients requires reference methods available only in specialized settings.

OBJECTIVE

To develop predictive fat mass equations for SMA I children based on simple measurements, and compare existing equations to the new disease-specific equations.

DESIGN

Demographic, clinical and anthropometric data were examined as potential predictors of the best candidate response variable and non-linear relations were taken into account by transforming continuous predictors with restricted cubic splines. Alternative models were fitted including all the dimensions revealed by cluster analysis of the predictors. The best models were then internally validated, quantifying optimism of the obtained performance measures. The contribution of nusinersen treatment to the unexplained variability of the final models was also tested.

RESULTS

A total of 153 SMA I patients were included in the study, as part of a longitudinal observational study in SMA children conducted at the International Center for the Assessment of Nutritional Status (ICANS), University of Milan. The sample equally represented both sexes (56% females) and a wide age range (from 3 months to 12 years, median 1.2 years). Four alternative models performed equally in predicting fat mass fraction (fat mass/body weight). The most convenient was selected and further presented. The selected model uses as predictors sex, age, calf circumference and the sum of triceps, suprailiac and calf skinfold thicknesses. The model showed high predictive ability (optimism corrected coefficient of determination, R² = 0.72) and internal validation indicated little optimism both in performance measures and model calibration. The addition of nusinersen as a predictor variable did not improve the prediction. The disease-specific equation was more accurate than the available fat mass equations.

CONCLUSIONS

The developed prediction model allows the assessment of body composition in SMA I children with simple and widely available measures and with reasonable accuracy.

Glucose and lipid metabolism disorders in children and adolescents with spinal muscular atrophy types 2 and 3

We aimed to estimate the prevalence of glucose and lipid metabolism disorders in children and adolescents with spinal muscular atrophy (SMA) types 2 and 3. A cross-sectional study was conducted. Medical history, anthropometric measurements, pubertal status, blood chemistry (glucose and insulin levels, lipid profile, aminotransferases, and hemoglobin A1c [HbA1c]), and liver ultrasound were obtained in all patients. Oral glucose tolerance test was performed in those with body mass index (BMI) >25th percentile or glucose or HbA1c levels in the prediabetic range. A total of 37 patients with SMA (22 type 2, 15 type 3) with a median age of 8.5 years (range 2-18.9 years) were included. Eleven patients (29.7%) met the criteria for prediabetes, but none had overt type 2 diabetes. Dyslipidemia was detected in 11 patients (29.7%), and 4 (10.8%) had hepatic steatosis on ultrasound. Sixteen patients (43.2%) had at least one abnormal finding (prediabetes, dyslipidemia, or hepatic steatosis); all but one were non-ambulatory and 12 (75%) had BMI ≥85th percentile. One young child developed fasting hypoglycemia. Our results suggest that non-ambulatory overweight/obese SMA patients are particularly prone to abnormalities in glucose and lipid metabolism. Young underweight patients might develop fasting hypoglycemia.

Nutrition status survey of type 2 and 3 spinal muscular atrophy in Chinese population

OBJECTIVE

To evaluate the nutritional status of children with SMA types II and III in a Chinese population.

METHODS

We performed a retrospective medical record review of prospectively collected data from children with SMA types II and III in a single centre. We analysed data including clinical parameters, anthropometrics, and 24-hour dietary intake records in our clinic.

RESULTS

We analysed the anthropometric data from 86 children with 69 (80%) SMAII and 17 (20%) SMAIII; 47 (55%) were female, mean age was 5.22 ± 3.73 years. The WAZ of the SMAII (n = 69) and SMAIII (n = 17) were -0.48 (IQR -1.69, 0.57) vs -0.53 (IQR -1.60, 0.55), P = 0.926; the HAZ were -0.62 (IQR -1.4, 0.3) vs -0.6 (IQR -1.61, 0.4), P=0.72; the BMIZ were -0.51 (IQR -1.53, 0.99) vs -0.08 (IQR -1.625, 1.125), P = 0.537.The dietary intake of 51 children was compared to the Chinese Dietary Reference Intakes (DRIs). The actual energy intake in SMAII was similar to the DRIs, but which in SMAIII was less than the DRIs (1312.4 ± 329.5 kcal vs. 1655 ± 640.1 kcal, P = 0.028). The protein intake in SMAII and SMAIII was higher than the DRIs (55 ± 16.3 g/d vs 30.2 ± 4.6 g/d, P < 0.05; 56.8 ± 18.1 g/d vs 41.5 ± 17.5 g/d, p = 0.22), and calcium intake was lower than the recommendation (507.7 ± 177.8 mg/d vs 731.7 ± 123.4 mg/d, P < 0.05; 478.4 ± 207.4 mg/d vs 478.4 ± 207.4 mg/d, P = 0.01). Swallowing on the Neuromuscular Disease Status Scale was 7.41 ± 0.5.

CONCLUSIONS

Children with SMAII and SMAIII were at risk for malnutrition and low calcium intake.

Feeding difficulties in children and adolescents with spinal muscular atrophy type 2

Disease course of feeding difficulties in spinal muscular atrophy type 2 is not well documented. Disease-modifying therapies rapidly change the trajectory of motor function and survival in spinal muscular atrophy, but effects on co-morbidities like bulbar function are unknown. We analysed data concerning feeding problems and their standard of care treatment in 146 patients with spinal muscular atrophy type 2. Data were collected from two separate cohorts: one single-centre retrospective chart review study from the United Kingdom (London), and one prospective questionnaire-based multicentre study from Italy. Cumulatively feeding difficulties were present in 88 patients (60%) in these 2 cohorts. Median age at onset of problems was 6.5years (range 0-16.5 years). Eighty-two patients (60%) showed periods of underweight according to age adjusted body mass index, and thirty-six patients (25%) showed malnourishment with a significant drop on their weight curves. Enteral feeding was indicated in 23 out of 72 patients in the UK cohort (32%) because of weight loss, oropharyngeal dysphagia or aspiration. Gastrostomy and its placement was generally well tolerated, uncomplicated in 96%, never reversed and performed without Nissen fundoplication in 66% of patients. After gastrostomy chest infections improved in 80% and nutritional status (e.g., Body Mass Index) in 84% of patients. These results show that feeding difficulties are a common problem in spinal muscular atrophy type 2. Treatment strategies should be tailor-made on the symptoms and needs of the individual patient.

Spinal muscular atrophy: Broad disease spectrum and sex-specific phenotypes

Spinal muscular atrophy (SMA) is one of the major genetic disorders associated with infant mortality. More than 90% of cases of SMA result from deletions of or mutations in the Survival Motor Neuron 1 (SMN1) gene. SMN2, a nearly identical copy of SMN1, does not compensate for the loss of SMN1 due to predominant skipping of exon 7. The spectrum of SMA is broad, ranging from prenatal death to infant mortality to survival into adulthood. All tissues, including brain, spinal cord, bone, skeletal muscle, heart, lung, liver, pancreas, gastrointestinal tract, kidney, spleen, ovary and testis, are directly and/or indirectly affected in SMA. Accumulating evidence on impaired mitochondrial biogenesis and defects in X chromosome-linked modifying factors, coupled with the sexual dimorphic nature of many tissues, point to sex-specific vulnerabilities in SMA. Here we review the role of sex in the pathogenesis of SMA.

Metabolic and Nutritional Issues Associated with Spinal Muscular Atrophy

Spinal muscular atrophy (SMA), the main genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of motor neurons in the anterior horn of the spinal cord, accompanied by muscle wasting. Pathomechanically, SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from the loss of the SMN1 gene. However, emerging research extends the pathogenic effect of SMN deficiency beyond motor neurons. A variety of metabolic abnormalities, especially altered fatty acid metabolism and impaired glucose tolerance, has been described in isolated cases of SMA; therefore, the impact of SMN deficiency in metabolic abnormalities has been speculated. Although the life expectancy of these patients has increased due to novel disease-modifying therapies and standardization of care, understanding of the involvement of metabolism and nutrition in SMA is still limited. Optimal nutrition support and metabolic monitoring are essential for patients with SMA, and a comprehensive nutritional assessment can guide personalized nutritional therapy for this vulnerable population. It has recently been suggested that metabolomics studies before and after the onset of SMA in patients can provide valuable information about the direct or indirect effects of SMN deficiency on metabolic abnormalities. Furthermore, identifying and quantifying the specific metabolites in SMA patients may serve as an authentic biomarker or therapeutic target for SMA. Here, we review the main epidemiological and mechanistic findings that link metabolic changes to SMA and further discuss the principles of metabolomics as a novel approach to seek biomarkers and therapeutic insights in SMA.

The endocrine manifestations of spinal muscular atrophy, a real-life observational study

The introduction of nusinersen, the first therapeutic modality for Spinal Muscular Atrophy (SMA) patients has raised hopes and led to construction of a multi-professional medical SMA service, including pediatric endocrinology. Our study aimed to provide a comprehensive description of the endocrine manifestations of SMA patients with variable degree of sarcopenia. Real-life clinical and laboratory data of 62 SMA patients (age range 3 months to 31 years, 24 type 1, 21 type 2, 17 type 3) were collected including: weight-status, self-reported information on puberty, current pubertal stage, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), basal gonadotropin and androgen levels. Precocious pubarche (mean age at onset 3.9 ± 2.8 years) was found in 24% (15/62) of the SMA cohort [45.9%(11/24) type 1 and 19%(4/21) type 2]. A higher HOMA-IR predicted precocious pubarche after adjustment for SMA type and age (OR=1.42; 95% CI, 1.05, 1.93, P = 0.025). Bilateral cryptorchidism was found in 60% of type 1 and 30% of type 2 boys; type 3 young adult males attained full puberty. Most of the young women had normal pubertal development and regular menses, regardless of degree of obesity. Our findings suggest that isolated precocious pubarche is associated with early-onset insulin resistance linked to severity of muscular atrophy.