Efficacy and safety of onasemnogene abeparvovec in children with spinal muscular atrophy type 1: real-world evidence from 6 infusion centres in the United Kingdom.

Background: Real-world data on the efficacy and safety of onasemnogene abeparvovec (OA) in spinal muscular atrophy (SMA) are needed, especially to overcome uncertainties around its use in older and heavier children. This study evaluated the efficacy and safety of OA in patients with SMA type 1 in the UK, including patients ≥2 years old and weighing ≥13.5 kg. Methods: This observational cohort study used data from patients with genetically confirmed SMA type 1 treated with OA between May 2021 and January 2023, at 6 infusion centres in the United Kingdom. Functional outcomes were assessed using age-appropriate functional scales. Safety analyses included review of liver function, platelet count, cardiac assessments, and steroid requirements. Findings: Ninety-nine patients (45 SMA therapy-naïve) were treated with OA (median age at infusion: 10 [range, 0.6-89] months; median weight: 7.86 [range, 3.2-20.2] kg; duration of follow-up: 3-22 months). After OA infusion, mean ± SD change in CHOP-INTEND score was 11.0 ± 10.3 with increased score in 66/78 patients (84.6%); patients aged <6 months had a 13.9 points higher gain in CHOP-INTEND score than patients ≥2 years (95% CI, 6.8-21.0; P < 0.001). Asymptomatic thrombocytopenia (71/99 patients; 71.7%), asymptomatic troponin-I elevation (30/89 patients; 33.7%) and transaminitis (87/99 patients; 87.9%) were reported. No thrombotic microangiopathy was observed. Median steroid treatment duration was 97 (range, 28-548) days with dose doubled in 35/99 patients (35.4%). There were 22.5-fold increased odds of having a transaminase peak >100 U/L (95% CI, 2.3-223.7; P = 0.008) and 21.2-fold increased odds of steroid doubling, as per treatment protocol (95% CI, 2.2-209.2; P = 0.009) in patients weighing ≥13.5 kg versus <8.5 kg. Weight at infusion was positively correlated with steroid treatment duration (r = 0.43; P < 0.001). Worsening transaminitis, despite doubling of oral prednisolone, led to treatment with intravenous methylprednisolone in 5 children. Steroid-sparing immunosuppressants were used in 5 children to enable steroid weaning. Two deaths apparently unrelated to OA were reported. Interpretation: OA led to functional improvements and was well tolerated with no persistent clinical complications, including in older and heavier patients. Funding: Novartis Innovative Therapies AG provided a grant for independent medical writing services.

Risdiplam for the treatment of adults with spinal muscular atrophy: Experience of the Northern Ireland neuromuscular service.

INTRODUCTION/AIMS: Risdiplam is the newest available treatment for patients with spinal muscular atrophy (SMA). There is little information on its use in adults. We present the clinical experience of adults with SMA treated with risdiplam through the Early Access to Medicines Scheme (EAMS) in Northern Ireland. METHODS: All adults with Type 2 SMA attending the regional neuromuscular clinic were offered risdiplam treatment. Patients had assessments of respiratory function, the Epworth Sleepiness Scale (ESS), Quality of Life Measure for People with Slowly Progressive and Genetic Neuromuscular Disease (QOLM), and Egen Klassifikation 2 (EK2) every 3 mo and the Revised Upper Limb Module for SMA (RULM) at baseline and 6 mo. All assessments other than the RULM were carried out virtually. RESULTS: Six of seven patients who were offered risdiplam consented to treatment through the EAMS (five female, one male, mean age 33.7 y). It was generally well tolerated other than skin photosensitivity in all patients. All patients remained on therapy at 9 mo. All reported meaningful improvements in overall strength, sense of wellbeing, and speech quality. There was no change in respiratory function, daytime hypersomnolence, or upper limb function (all p > .05). There was improvement in the QOLM (p = .027) and EK2 (p = .009). DISCUSSION: Our study raises hopes that risdiplam may be efficacious in adults; however, more systematic studies in larger cohorts are needed before drawing any definitive conclusions. This study also demonstrated the feasibility of virtual assessments.

Prediagnosis pathway benchmarking audit in patients with Duchenne muscular dystrophy.

OBJECTIVE: To describe age and time at key stages in the Duchenne muscular dystrophy (DMD) prediagnosis pathway at selected centres to identify opportunities for service improvement. DESIGN: A multicentre retrospective national audit. SETTING: Nine tertiary neuromuscular centres across the UK and Ireland. A prior single-centre UK audit of 20 patients with no DMD family history provided benchmark criteria. PATIENTS: Patients with a definitive diagnosis of DMD documented within 3 years prior to December 2018 (n=122). MAIN OUTCOME MEASURES: Mean age (months) at four key stages in the DMD diagnostic pathway and mean time (months) of presentational and diagnostic delay, and time from first reported symptoms to definitive diagnosis. Type of symptoms was also recorded. RESULTS: Overall, mean age at definitive diagnosis, age at first engagement with healthcare professional (HCP) and age at first reported symptoms were 53.9±29.7, 49.9±28.9 and 36.4±26.8 months, respectively. The presentational delay and time to diagnosis were 21.1 (±21.1) and 4.6 (±7.9) months, respectively. The mean time from first reported symptoms to definitive diagnosis was 24.2±20.9. The percentages of patients with motor and/or non-motor symptoms recorded were 88% (n=106/121) and 47% (n=57/121), respectively. CONCLUSIONS: Majority of data mirrored the benchmark audit. However, while the time to diagnosis was shorter, a presentational delay was observed. Failure to recognise early symptoms of DMD could be a contributing factor and represents an unmet need in the diagnosis pathway. Methods determining how to improve this need to be explored.

Making sense of missense variants in TTN-related congenital myopathies.

Mutations in the sarcomeric protein titin, encoded by TTN, are emerging as a common cause of myopathies. The diagnosis of a TTN-related myopathy is, however, often not straightforward due to clinico-pathological overlap with other myopathies and the prevalence of TTN variants in control populations. Here, we present a combined clinico-pathological, genetic and biophysical approach to the diagnosis of TTN-related myopathies and the pathogenicity ascertainment of TTN missense variants. We identified 30 patients with a primary TTN-related congenital myopathy (CM) and two truncating variants, or one truncating and one missense TTN variant, or homozygous for one TTN missense variant. We found that TTN-related myopathies show considerable overlap with other myopathies but are strongly suggested by a combination of certain clinico-pathological features. Presentation was typically at birth with the clinical course characterized by variable progression of weakness, contractures, scoliosis and respiratory symptoms but sparing of extraocular muscles. Cardiac involvement depended on the variant position. Our biophysical analyses demonstrated that missense mutations associated with CMs are strongly destabilizing and exert their effect when expressed on a truncating background or in homozygosity. We hypothesise that destabilizing TTN missense mutations phenocopy truncating variants and are a key pathogenic feature of recessive titinopathies that might be amenable to therapeutic intervention.

Endocrine and Growth Abnormalities in 4H Leukodystrophy Caused by Variants in POLR3A, POLR3B, and POLR1C.

CONTEXT: 4H or POLR3-related leukodystrophy is an autosomal recessive disorder typically characterized by hypomyelination, hypodontia, and hypogonadotropic hypogonadism, caused by biallelic pathogenic variants in POLR3A, POLR3B, POLR1C, and POLR3K. The endocrine and growth abnormalities associated with this disorder have not been thoroughly investigated to date. OBJECTIVE: To systematically characterize endocrine abnormalities of patients with 4H leukodystrophy. DESIGN: An international cross-sectional study was performed on 150 patients with genetically confirmed 4H leukodystrophy between 2015 and 2016. Endocrine and growth abnormalities were evaluated, and neurological and other non-neurological features were reviewed. Potential genotype/phenotype associations were also investigated. SETTING: This was a multicenter retrospective study using information collected from 3 predominant centers. PATIENTS: A total of 150 patients with 4H leukodystrophy and pathogenic variants in POLR3A, POLR3B, or POLR1C were included. MAIN OUTCOME MEASURES: Variables used to evaluate endocrine and growth abnormalities included pubertal history, hormone levels (estradiol, testosterone, stimulated LH and FSH, stimulated GH, IGF-I, prolactin, ACTH, cortisol, TSH, and T4), and height and head circumference charts. RESULTS: The most common endocrine abnormalities were delayed puberty (57/74; 77% overall, 64% in males, 89% in females) and short stature (57/93; 61%), when evaluated according to physician assessment. Abnormal thyroid function was reported in 22% (13/59) of patients. CONCLUSIONS: Our results confirm pubertal abnormalities and short stature are the most common endocrine features seen in 4H leukodystrophy. However, we noted that endocrine abnormalities are typically underinvestigated in this patient population. A prospective study is required to formulate evidence-based recommendations for management of the endocrine manifestations of this disorder.

How to use: creatine kinase.

Creatine kinase (CK) remains an essential tool for assessment of muscular weakness and pain in children despite the advent of advanced diagnostic tests in this field. It is also useful in diagnosing and monitoring various other conditions. This article will explore the physiology of CK and clinical situations where the estimation of CK can help the clinicians' decision-making process with the diagnosis and management of these conditions. Some clinical scenarios are used to highlight how the tests can be used in different clinical situations. The role of CK as a biomarker of myocardial injury has been purposefully omitted in this article.

Infantile Onset of Spinocerebellar Ataxia Type 5 (SCA-5) in a 6 Month Old with Ataxic Cerebral Palsy.

Spinocerebellar ataxia type 5 (SCA-5) is a predominantly slowly progressive adult onset ataxia. We describe a child with a presentation of ataxic cerebral palsy (CP) and developmental delay at 6 months of age. Genetic testing confirmed a c.812C>T p.(Thr271Ile) mutation within the SPTBN2 gene. Seven previous cases of infantile onset SCA-5 are reported in the literature, four of which had a CP presentation. Early onset of SCA-5 presents with ataxic CP and is a rare cause of cerebral palsy.

Interventions to prevent and treat corticosteroid-induced osteoporosis and prevent osteoporotic fractures in Duchenne muscular dystrophy.

BACKGROUND: Corticosteroid treatment is considered the 'gold standard' for Duchenne muscular dystrophy (DMD); however, it is also known to induce osteoporosis and thus increase the risk of vertebral fragility fractures. Good practice in the care of those with DMD requires prevention of these adverse effects. Treatments to increase bone mineral density include bisphosphonates and vitamin D and calcium supplements, and in adolescents with pubertal delay, testosterone. Bone health management is an important part of lifelong care for patients with DMD. OBJECTIVES: To assess the effects of interventions to prevent or treat osteoporosis in children and adults with DMD taking long-term corticosteroids; to assess the effects of these interventions on the frequency of vertebral fragility fractures and long-bone fractures, and on quality of life; and to assess adverse events. SEARCH METHODS: On 12 September 2016, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL Plus to identify potentially eligible trials. We also searched the Web of Science ISI Proceedings (2001 to September 2016) and three clinical trials registries to identify unpublished studies and ongoing trials. We contacted correspondence authors of the included studies in the review to obtain information on unpublished studies or work in progress. SELECTION CRITERIA: We considered for inclusion in the review randomised controlled trials (RCTs) and quasi-RCTs involving any bone health intervention for corticosteroid-induced osteoporosis and fragility fractures in children, adolescents, and adults with a confirmed diagnosis of DMD. The interventions might have included oral and intravenous bisphosphonates, vitamin D supplements, calcium supplements, dietary calcium, testosterone, and weight-bearing activity. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed reports and selected potential studies for inclusion, following standard Cochrane methodology. We contacted study authors to obtain further information for clarification on published work, unpublished studies, and work in progress. MAIN RESULTS: We identified 18 potential studies, of which two, currently reported only as abstracts, met the inclusion criteria for this review. Too little information was available for us to present full results or adequately assess risk of bias. The participants were children aged five to 15 years with DMD, ambulant and non-ambulant. The interventions were risedronate versus no treatment in one trial (13 participants) and whole-body vibration versus a placebo device in the second (21 participants). Both studies reported improved bone mineral density with the active treatments, with no improvement in the control groups, but the abstracts did not compare treatment and control conditions. All children tolerated whole-body vibration treatment. No study provided information on adverse events. Two studies are ongoing: one investigating whole-body vibration, the other investigating zoledronic acid. AUTHORS' CONCLUSIONS: We know of no high-quality evidence from RCTs to guide use of treatments to prevent or treat corticosteroid-induced osteoporosis and reduce the risk of fragility fractures in children and adults with DMD; only limited results from two trials reported in abstracts were available. We await formal trial reports. Findings from two ongoing relevant studies and two trials, for which only abstracts are available, will be important in future updates of this review.

Dystrophin Exon 29 Nonsense Mutations Cause a Variably Mild Phenotype.

BACKGROUND: Nonsense mutations in the dystrophin gene usually result in a severe Duchenne muscular dystrophy phenotype. FINDINGS: We describe a 7-year-old boy with a rare pathogenic mutation in exon 29 c.3940C>T p.(Arg1314Ter) resulting in exon skipping, in turn rescuing the phenotype from a severe Duchenne type to a milder Becker muscular dystrophy type. No adults have been described with this mutation to date. CONCLUSIONS: Exon skipping of exon 29 results in a higher level of functional dystrophin. Some cases of muscular dystrophy may still require muscle biopsy to determine optimal management and pharmaceutical treatment options.

Sydenham's chorea: not gone but perhaps forgotten.

Sydenham's chorea (SC) is characterised by chorea, emotional lability and hypotonia. In this study, we investigated the incidence and clinical presentation of childhood SC in Ireland (years 2006-2014). Nineteen cases were diagnosed. Five patients had rheumatic fever. An increasing trend with an incidence of 0.23/100 000 is reported. As most referral diagnoses included psychogenic illness, head injury and stroke, modern physicians may not be aware of this age old illness. A review of the manifestations and diagnosis of SC is presented.

Clinical spectrum of 4H leukodystrophy caused by POLR3A and POLR3B mutations.

OBJECTIVE: To study the clinical and radiologic spectrum and genotype-phenotype correlation of 4H (hypomyelination, hypodontia, hypogonadotropic hypogonadism) leukodystrophy caused by mutations in POLR3A or POLR3B. METHODS: We performed a multinational cross-sectional observational study of the clinical, radiologic, and molecular characteristics of 105 mutation-proven cases. RESULTS: The majority of patients presented before 6 years with gross motor delay or regression. Ten percent had an onset beyond 10 years. The disease course was milder in patients with POLR3B than in patients with POLR3A mutations. Other than the typical neurologic, dental, and endocrine features, myopia was seen in almost all and short stature in 50%. Dental and hormonal findings were not invariably present. Mutations in POLR3A and POLR3B were distributed throughout the genes. Except for French Canadian patients, patients from European backgrounds were more likely to have POLR3B mutations than other populations. Most patients carried the common c.1568T>A POLR3B mutation on one allele, homozygosity for which causes a mild phenotype. Systematic MRI review revealed that the combination of hypomyelination with relative T2 hypointensity of the ventrolateral thalamus, optic radiation, globus pallidus, and dentate nucleus, cerebellar atrophy, and thinning of the corpus callosum suggests the diagnosis. CONCLUSIONS: 4H is a well-recognizable clinical entity if all features are present. Mutations in POLR3A are associated with a more severe clinical course. MRI characteristics are helpful in addressing the diagnosis, especially if patients lack the cardinal non-neurologic features.

DOK7 congenital myasthenic syndrome in childhood: early diagnostic clues in 23 children.

Mutations in DOK7 are a common cause of congenital myasthenia. Treatment with ephedrine or salbutamol is effective, but diagnosis is often delayed. The aim of our study was to find early clues to the diagnosis of DOK7 congenital myasthenic syndrome. We included 23 children of 20 families. Onset of symptoms ranged from birth to age 3 years. 13 presented at birth with feeding difficulties, 11 with stridor (documented vocal cord palsy in 7), 3/11 with hypotonia/poor head control. Weakness was more pronounced proximally in all, axial in early presenting infants. Muscle biopsy showed non-specific features in 15/16, type 1 fibre predominance in 14/16, areas devoid of oxidative enzyme activity in 7/16. Muscle imaging was normal in 8/10, 2/10 showed mild non-specific changes. A diagnostic clue suggesting CMS rather than myopathy was the discrepancy between muscle imaging or histology findings compared with the degree of weakness. Repetitive nerve stimulation and stimulation single fibre electromyography were pathological in 9/17 and 13/14, respectively. In conclusion, stridor and feeding difficulties at birth or progressive weakness despite normal milestones in infancy point to the diagnosis and should lead to neurophysiological and genetic investigation. Fatigability can be absent or easily missed in the first years of life.

Adherence to antiepileptic medicines in children: a multiple-methods assessment involving dried blood spot sampling.

PURPOSE: To evaluate adherence to prescribed antiepileptic drugs (AEDs) in children with epilepsy using a combination of adherence-assessment methods. METHODS: A total of 100 children with epilepsy (≤17 years old) were recruited. Medication adherence was determined via parental and child self-reporting (≥9 years old), medication refill data from general practitioner (GP) prescribing records, and via AED concentrations in dried blood spot (DBS) samples obtained from children at the clinic and via self- or parental-led sampling in children's own homes. The latter were assessed using population pharmacokinetic modeling. Patients were deemed nonadherent if any of these measures were indicative of nonadherence with the prescribed treatment. In addition, beliefs about medicines, parental confidence in seizure management, and the presence of depressed mood in parents were evaluated to examine their association with nonadherence in the participating children. KEY FINDINGS: The overall rate of nonadherence in children with epilepsy was 33%. Logistic regression analysis indicated that children with generalized epilepsy (vs. focal epilepsy) were more likely (odds ratio [OR] 4.7, 95% confidence interval [CI] 1.37-15.81) to be classified as nonadherent as were children whose parents have depressed mood (OR 3.6, 95% CI 1.16-11.41). SIGNIFICANCE: This is the first study to apply the novel methodology of determining adherence via AED concentrations in clinic and home DBS samples. The present findings show that the latter, with further development, could be a useful approach to adherence assessment when combined with other measures including parent and child self-reporting. Seizure type and parental depressed mood were strongly predictive of nonadherence.

Analysis of factors influencing admission to intensive care following convulsive status epilepticus in children.

OBJECTIVES: To identify clinical features and therapeutic decisions that influence admission to the Intensive Care unit (ICU) in children presenting with convulsive status epilepticus (CSE). METHODS: We evaluated 47 admissions with status epilepticus to a tertiary paediatric hospital A&E over a three year period (2003-2006). Following initial management 23 episodes required admission to ICU and 24 were managed on a paediatric ward. We compared clinical, demographic data and compliance with our CSE protocol between the ICU and ward groups. RESULTS: Median age at presentation in the ICU group was 17 months (range 3 months-11 years) compared to 46 months in the ward group (range 3 months-10 years). Fifty per cent of patients in both groups had a previous history of seizures. Median duration of pre-hospital seizure activity was 30 min in both groups. More than two doses of benzodiazepines were given as first line medication in 62% of the ICU group and 33% of the ward group. Among children admitted to ICU with CSE, 26% had been managed according to the CSE protocol, compared to 66% of children who were admitted to a hospital ward. Febrile seizures were the most common aetiology in both groups. CONCLUSION: Younger age at presentation, administration of more than two doses of benzodiazepines and deviation from the CSE protocol appear to be factors which influence admission of children to ICU. Recognition of pre-hospital administration of benzodiazepines and adherence to therapeutic guidelines may reduce the need for ventilatory support in this group.

Central hypoventilation syndrome after Haemophilus influenzae type b meningitis and herpes infection.

A case of central hypoventilation syndrome was identified in a child with brainstem and cervical cord injury following Haemophilus influenzae type b meningitis and extensive herpes simplex infection. This process resulted in a spastic tetraplegia, and the child continues to require respiratory support. Possible mechanisms of causation are discussed including an evolving, progressive inflammatory or vasculitic process in the setting of transient immunosuppression.