BACKGROUNDSpinal muscular atrophy is an autosomal recessive neuromuscular disorder that is caused by an insufficient level of survival motor neuron (SMN) protein. Nusinersen is an antisense oligonucleotide drug that modifies pre-messenger RNA splicing of the SMN2 gene and thus promotes increased production of full-length SMN protein. METHODSWe conducted a randomized, double-blind, sham-controlled, phase 3 efficacy and safety trial of nusinersen in infants with spinal muscular atrophy. The primary end points were a motor-milestone response (defined according to results on the Hammersmith Infant Neurological Examination) and event-free survival (time to death or the use of permanent assisted ventilation). Secondary end points included overall survival and subgroup analyses of event-free survival according to disease duration at screening. Only the first primary end point was tested in a prespecified interim analysis. To control the overall type I error rate at 0.05, a hierarchical testing strategy was used for the second primary end point and the secondary end points in the final analysis. RESULTSIn the interim analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (21 of 51 infants [41%] vs. 0 of 27 [0%], P<0.001), and this result prompted early termination of the trial. In the final analysis, a significantly higher percentage of infants in the nusinersen group than in the control group had a motor-milestone response (37 of 73 infants [51%] vs. 0 of 37 [0%]), and the likelihood of event-free survival was higher in the nusinersen group than in the control group (hazard ratio for death or the use of permanent assisted ventilation, 0.53; P = 0.005). The likelihood of overall survival was higher in the nusinersen group than in the control group (hazard ratio for death, 0.37; P = 0.004), and infants with a shorter disease duration at screening were more likely than those with a longer disease duration to benefit from nusinersen. The incidence and severity of adverse events were similar in the two groups. CONCLUSIONSAmong infants with spinal muscular atrophy, those who received nusinersen were more likely to be alive and have improvements in motor function than those in the control group. Early treatment may be necessary to maximize the benefit of the drug. (Funded by Biogen and Ionis Pharmaceuticals; ENDEAR ClinicalTrials.gov number, NCT02193074.)

The defective gene DYS, which is responsible for familial dysautonomia (FD) and has been mapped to a 0.5-cM region on chromosome 9q31, has eluded identification. We identified and characterized the RNAs encoded by this region of chromosome 9 in cell lines derived from individuals homozygous for the major FD haplotype, and we observed that the RNA encoding the IkappaB kinase complex-associated protein (IKAP) lacks exon 20 and, as a result of a frameshift, encodes a truncated protein. Sequence analysis reveals a T-->C transition in the donor splice site of intron 20. In individuals bearing a minor FD haplotype, a missense mutation in exon 19 disrupts a consensus serine/threonine kinase phosphorylation site. This mutation results in defective phosphorylation of IKAP. These mutations were observed to be present in a random sample of Ashkenazi Jewish individuals, at approximately the predicted carrier frequency of FD. These findings demonstrate that mutations in the gene encoding IKAP are responsible for FD.

Objective.To describe the respiratory trajectories and their correlation with motor function in an international paediatric cohort of patients with type 2 and non-ambulant type 3 spinal muscular atrophy (SMA).Methods.Eight-year retrospective observational study of patients in the iSMAc natural history study. We retrieved anthropometrics, forced vital capacity (FVC) absolute, FVC% predicted (FVC%P.), Non-Invasive ventilation (NIV) requirement. Hammersmith functional motor scale (HFMS) and Revised performance of upper limb (RULM) were correlated with respiratory function. We excluded patients in interventional clinical trials and on Nusinersen commercial therapy.Results.There were 437 patients with SMA: 348 type 2, 89 non-ambulant type 3. Mean age at first visit was 6.9(±4.4) and 11.1(±4) years. In SMA type 2 FVC%P declined by 4.2%/year from 5 to 13 years, followed by a slower decline (1.0%/year). In type 3 FVC%P declined by 6.3%/year between 8 and 13 years, followed by a slower decline (0.9%/year). 39% SMA type 2 and 9% type 3 required NIV at median age 5.0(1.8-16.6) and 15.1(13.8-16.3) years. 84% SMA type 2 and 80% type 3 had scoliosis, 54% and 46% required surgery, which did not significantly affect respiratory decline. FVC%P positively correlated with HFMS and RULM in both subtypes.Conclusions.In SMA type 2 and non-ambulant type 3 lung function declines differently, with a common levelling after age 13 years. Lung and motor function correlated in both subtypes. Our data further defines the milder SMA phenotypes and provides novel information to benchmark the long-term efficacy of new treatments for SMA.

Spinal muscular atrophy (SMA) is an autosomal recessive, neurodegenerative disease caused by biallelic mutations in the survival motor neuron 1 (SMN1) gene. SMA is characterized by motor neuron degeneration, resulting in progressive muscle atrophy and weakness. Before the emergence of disease-modifying therapies, children with the most severe form of SMA would never achieve the ability to sit independently.Only 8% survived beyond 20 months of age without permanent ventilator support.One such therapy, onasemnogene abeparvovec, an adeno-associated virus-based gene replacement therapy, delivers functional human SMN through a one-time intravenous infusion. In addition to substantially improving survival, onasemnogene abeparvovec was found to increase motor milestone attainment and reduce the need for respiratory or nutritional support in many patients. This expert opinion provides recommendations and practical considerations on the patient-centered decisions to use onasemnogene abeparvovec. Recommendations include the need for patientcentered multidisciplinary care and patient selection to identify those with underlying medical conditions or active infections to reduce risks. We also describe the importance of retesting patients with elevated anti-adeno-associated virus serotype 9 antibodies. Recommendations for prednisolone tapering and monitoring for potential adverse events, including hepatotoxicity and thrombotic microangiopathy, are described. The need for caregiver education on managing day-to-day care at time of treatment and patient-and family-centered discussions on realistic expectations are also recommended. We detail the importance of following standard-of-care guidance and long-term monitoring of all children with SMA who have received one or more

Abstract:Purpose To determine change in motor function after treatment with nusinersen in adults with spinal muscular atrophy (SMA) during the first two years of commercial availability.Recent Findings All forty-two adult SMA patients (mean age: 34 years, range 17-66) receiving nusinersen at PNCR sites were assessed for a mean of 12.5 months (range 3-24 months). Data collected prospectively generated a mean annual rate of change over time determined using linear mixed effects models. Motor and ventilatory measures showed positive changes distinct from the progressive decline expected in untreated adults. All participants tolerated nusinersen with normal surveillance labs and no significant adverse events.Summary Trends of improvement in functional motor, patient-reported, and ventilatory measures, suggested nusinersen benefit in adults with SMA, including the chronic, weaker phenotype. Longer duration and larger studies are needed to more firmly establish nusinersen efficacy in adults with SMA.