Children and young adults with spinal muscular atrophy treated with nusinersen.

INTRODUCTION: Treatment of children with spinal muscular atrophy (SMA) now includes disease modifying drugs such as nusinersen. Real-world data can provide new insight on the efficacy and safety of nusinersen for treatment of children with SMA. AIM: The aim of our study is to evaluate the effect of treatment of children and young adults with SMA type I, II and III at various stages of the disease after 14 months of treatment with nusinersen. METHODS: In this prospective, two-center (in Slovenia and Czech Republic) study, data from all patients with a genetically confirmed diagnosis of SMA before 19 years of age who were treated with nusinersen were collected before initiation of treatment, and after 6 and 14 months of treatment. Various standardized motor scales and a questionnaire that focused on daily-life activities were used. RESULTS: Form both centers, 61 patients from 2 months to 19 years of age were enrolled in the study. Sixteen had SMA type I (median age 5.2 years); 32 had SMA type II (median age 8.9 years); and 13 had SMA type III (median age 8.6 years). Patients had 2-4 copies of the SMN2 gene. One patient died in the study period and one discontinued treatment. After 14 months of treatment, SMA type I (p = 0.002) and type II (p = 0.002) patients had significantly better outcomes, while type III patients showed a trend towards improvement (p = 0.051) on motor scales. Younger age at the initiation of treatment and a higher number of SMN2 copies is related to a better outcome. Younger children also seem to improve faster compared to older children. No serious side effects were reported. CONCLUSION: The results of our study which included patients of various SMA types and stages of the disease suggest that treatment with nusinersen benefits patients, regardless of SMA type. Earlier age at the initiation of treatment and a higher number of SMN2 copies were related to a better outcome, however even some patients of higher age and/or later stage of the disease benefited from the treatment. Our study also suggests that nusinersen is safe to use, as no major side effects, requiring discontinuation of treatment, were reported. There is an unmet need for novel standardized tests and biomarkers, which could help guide clinician's decisions on the selection of best treatment options and monitor treatment success.

New genotype-phenotype correlations in a large European cohort of patients with sarcoglycanopathy.

Sarcoglycanopathies comprise four subtypes of autosomal recessive limb-girdle muscular dystrophies (LGMDR3, LGMDR4, LGMDR5 and LGMDR6) that are caused, respectively, by mutations in the SGCA, SGCB, SGCG and SGCD genes. In 2016, several clinicians involved in the diagnosis, management and care of patients with LGMDR3-6 created a European Sarcoglycanopathy Consortium. The aim of the present study was to determine the clinical and genetic spectrum of a large cohort of patients with sarcoglycanopathy in Europe. This was an observational retrospective study. A total of 33 neuromuscular centres from 13 different European countries collected data of the genetically confirmed patients with sarcoglycanopathy followed-up at their centres. Demographic, genetic and clinical data were collected for this study. Data from 439 patients from 13 different countries were collected. Forty-three patients were not included in the analysis because of insufficient clinical information available. A total of 159 patients had a confirmed diagnosis of LGMDR3, 73 of LGMDR4, 157 of LGMDR5 and seven of LGMDR6. Patients with LGMDR3 had a later onset and slower progression of the disease. Cardiac involvement was most frequent in LGMDR4. Sixty per cent of LGMDR3 patients carried one of the following mutations, either in a homozygous or heterozygous state: c.229C>T, c.739G>A or c.850C>T. Similarly, the most common mutations in LMGDR5 patients were c.525delT or c.848G>A. In LGMDR4 patients the most frequent mutation was c.341C>T. We identified onset of symptoms before 10 years of age and residual protein expression lower than 30% as independent risk factors for losing ambulation before 18 years of age, in LGMDR3, LGMDR4 and LGMDR5 patients. This study reports clinical, genetic and protein data of a large European cohort of patients with sarcoglycanopathy. Improving our knowledge about these extremely rare autosomal recessive forms of LGMD was helped by a collaborative effort of neuromuscular centres across Europe. Our study provides important data on the genotype-phenotype correlation that is relevant for the design of natural history studies and upcoming interventional trials in sarcoglycanopathies.