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.)
SUMMARYWe performed STXBP1 mutation analyses in 86 patients with various types of epilepsies, including 10 patients with OS, 43 with West syndrome, 2 with Lennox-Gastaut syndrome, 12 with symptomatic generalized epilepsy, 14 with symptomatic partial epilepsy, and 5 with other undetermined types of epilepsy. In all patients, the etiology was unknown, but ARX and CDKL5 mutations were negative in all cases. All coding exons of STXBP1 were analyzed by direct-sequencing. Two de novo nucleotide alterations of STXBP1 were identified in two patients with Ohtahara and West syndrome, respectively. No de novo or deleterious mutations in STXBP1 were found in the remaining 84 patients with various types of symptomatic epilepsies. This is the first case report showing that STXBP1 mutations caused West syndrome from the onset of epilepsy. STXBP1 analysis should be considered as an etiology of symptomatic West syndrome without explainable cause.
SUMMARYPurpose: Genetic mutations of the cyclin-dependent kinase-like 5 gene (CDKL5) have been reported in patients with epileptic encephalopathy, which is characterized by intractable seizures and severe-to-profound developmental delay. We investigated the clinical relevance of CDKL5 alterations in both genders. Methods: A total of 125 patients with epileptic encephalopathy were examined for genomic copy number aberrations, and 119 patients with no such aberrations were further examined for CDKL5 mutations. Five patients with Rett syndrome, who did not show methyl CpG-binding protein 2 gene (MECP2) mutations, were also examined for CDKL5 mutations. Key Findings: One male and three female patients showed submicroscopic deletions including CDKL5, and two male and six female patients showed CDKL5 nucleotide alterations. Development of early onset seizure was a characteristic clinical feature for the patients with CDKL5 alterations in both genders despite polymorphous seizure types, including myoclonic seizures, tonic seizures, and spasms. Severe developmental delays and mild frontal lobe atrophies revealed by brain magnetic resonance imaging (MRI) were observed in almost all patients, and there was no gender difference in phenotypic features. Significance: We observed that 5% of the male patients and 14% of the female patients with epileptic encephalopathy had CDKL5 alterations. These findings indicate that alterations in CDKL5 are associated with early epileptic encephalopathy in both female and male patients.
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