Summary Objective Epilepsy is a common neurologic disorder of childhood. To determine the genetic diagnostic yield in epileptic encephalopathy, we performed a retrospective cohort study in a single epilepsy genetics clinic. Methods We included all patients with intractable epilepsy, global developmental delay, and cognitive dysfunction seen between January 2012 and June 2014 in the Epilepsy Genetics Clinic. Electronic patient charts were reviewed for clinical features, neuroimaging, biochemical investigations, and molecular genetic investigations including targeted next‐generation sequencing of epileptic encephalopathy genes. Results Genetic causes were identified in 28% of the 110 patients: 7% had inherited metabolic disorders including pyridoxine dependent epilepsy caused by ALDH7A1 mutation, Menkes disease, pyridox(am)ine‐5‐phosphate oxidase deficiency, cobalamin G deficiency, methylenetetrahydrofolate reductase deficiency, glucose transporter 1 deficiency, glycine encephalopathy, and pyruvate dehydrogenase complex deficiency; 21% had other genetic causes including genetic syndromes, pathogenic copy number variants on array comparative genomic hybridization, and epileptic encephalopathy related to mutations in the SCN1A, SCN2A, SCN8A, KCNQ2, STXBP1, PCDH19, and SLC9A6 genes. Forty‐five percent of patients obtained a genetic diagnosis by targeted next‐generation sequencing epileptic encephalopathy panels. It is notable that 4.5% of patients had a treatable inherited metabolic disease. Significance To the best of our knowledge, this is the first study to combine inherited metabolic disorders and other genetic causes of epileptic encephalopathy. Targeted next‐generation sequencing panels increased the genetic diagnostic yield from <10% to >25% in patients with epileptic encephalopathy.

Objective Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a newly recognized anti-neuronal antibody-mediated inflammatory brain disease causing severe psychiatric and neurological deficits in previously healthy children. The aim of this study was to report characteristic clinical features and outcomes of children diagnosed with anti-NMDAR encephalitis. Methods Consecutive children presenting with newly acquired psychiatric and/or neurologic deficits consistent with anti-NMDAR encephalitis and evidence of CNS inflammation were screened over a 12-month period. Children were included in the study if they had confirmatory evidence of anti-NMDAR antibodies in the serum and/or cerebrospinal fluid (CSF). Details of clinical presentation and results of investigations were reported. Type and duration of treatment and outcomes at last follow-up were documented. Results Seven children were screened and three children with anti-NMDAR encephalitis were identified. All patients presented with neurological or psychiatric (‘neuropsychiatric’) abnormalities, seizures, speech disorder, sleep disturbance, and fluctuating level of consciousness. The two older patients also had more prominent psychiatric features, while the younger child had significant autonomic instability and prominent involuntary movement disorder. None had an underlying tumor. Immunosuppressive therapies resulted in near or complete recovery; however, two of the patients had early relapse requiring re-treatment. Conclusion Anti-NMDAR encephalitis is an important cause of neuropsychiatric deficits in children that must be included in the differential diagnosis of CNS vasculitis and other inflammatory brain diseases. Early diagnosis and treatment are essential for neurologic recovery.

ObjectiveTo identify underlying genetic causes in patients with pediatric movement disorders by genetic investigations.MethodsAll patients with a movement disorder seen in a single Pediatric Genetic Movement Disorder Clinic were included in this retrospective cohort study. We reviewed electronic patient charts for clinical, neuroimaging, biochemical, and molecular genetic features. DNA samples were used for targeted direct sequencing, targeted next-generation sequencing, or whole exome sequencing.ResultsThere were 51 patients in the Pediatric Genetic Movement Disorder Clinic. Twenty-five patients had dystonia, 27 patients had ataxia, 7 patients had chorea-athetosis, 8 patients had tremor, and 7 patients had hyperkinetic movements. A genetic diagnosis was confirmed in 26 patients, including in 20 patients with ataxia and 6 patients with dystonia. Targeted next-generation sequencing panels confirmed a genetic diagnosis in 9 patients, and whole exome sequencing identified a genetic diagnosis in 14 patients.ConclusionsWe report a genetic diagnosis in 26 (51%) patients with pediatric movement disorders seen in a single Pediatric Genetic Movement Disorder Clinic. A genetic diagnosis provided either disease-specific treatment or effected management in 10 patients with a genetic diagnosis, highlighting the importance of early and specific diagnosis.