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.)

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Neuromuscular ultrasound has become an essential tool in the diagnostic evaluation of various neuromuscular disorders, and, as such, there is growing interest in neuromuscular ultrasound training. Effective training is critical in mastering this modality. Our aim was to develop consensus‐based guidelines for neuromuscular ultrasound training courses. A total of 18 experts participated. Expert opinion was sought through the Delphi method using 4 consecutive electronic surveys. A high degree of consensus was achieved with regard to the general structure of neuromuscular ultrasound training; the categorization of training into basic, intermediate, and advanced levels; the learning objectives; and the curriculum for each level. In this study, a group of neuromuscular ultrasound experts established consensus‐based guidelines for neuromuscular ultrasound training. These guidelines can be used in the development of the specialty and the standardization of neuromuscular ultrasound training courses and workshops.

The alpha-dystroglycanopathies are genetically heterogeneous muscular dystrophies that result from hypoglycosylation of alpha-dystroglycan (α-DG). Alpha-dystroglycan is an essential link between the extracellular matrix and the muscle fiber sarcolemma, and proper glycosylation is critical for its ability to bind to ligands in the extracellular matrix. We sought to identify the genetic basis of alpha-dystroglycanopathy in a family wherein the affected individuals presented with congenital muscular dystrophy, brain abnormalities and generalized epilepsy. We performed whole exome sequencing and identified compound heterozygous GMPPB mutations in the affected children. GMPPB is an enzyme in the glycosylation pathway, and GMPPB mutation were recently linked to eight cases of alpha-dystroglycanopathy with a range of symptoms. We identified a novel mutation in GMPPB (p.I219T) as well as a previously published mutation (p.R287Q). Thus, our work further confirms a role for GMPPB defects in alpha-dystroglycanopathy, and suggests that glycosylation may play a role in the neuronal membrane channels or networks involved in the physiology of generalized epilepsy syndromes.

Our objective was to examine the value of phrenic nerve conduction studies (PNCS) in quantifying diaphragm dysfunction in ALS, as no ideal test of respiratory insufficiency exists in ALS. We prospectively recorded bilateral PNCS, forced vital capacity (FVC), maximum inspiratory pressure (MIP), sniff nasal inspiratory pressure (SNIP), respiratory rate, ALSFRS-R, and respiratory symptoms in 100 ALS patients attending our clinic over a nine-month period. Survival data were collected for two years. Results showed that PNCS were reproducible and well tolerated. When the Pamp was abnormal (<0.3 mV), the relative risk of a respiratory rate >18 was 7.2 (95% CI 2.2-37.2, p <0.01) compared with a Pamp ≥0.3 mV. Similarly, the relative risk of orthopnea was 3.5 (95% CI 1.6-8.7, p <0.01) and dyspnea 2.4 (95% CI 1.4-4.0, p <0.01). FVC had the strongest correlation with Pamp (R(2) = 0.48 (p <0.001)). Fourteen of 15 patients with a FVC <50% had a Pamp <0.3 mV. However, eight with a Pamp <0.3 had a FVC >80%. The median survival was 1.07 years when the Pamp was <0.3 mV and >2 years when the Pamp was >0.3 mV (p <0.001). In conclusion, the phrenic Pamp correlated closely with multiple symptoms, signs, and laboratory measures of respiratory insufficiency and may prove to be a useful biomarker of respiratory dysfunction in ALS.