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This study aimed to provide comprehensive diagnostic and candidate analyses in a pediatric rare disease cohort through the Genomic Answers for Kids program.Extensive analyses of 960 families with suspected genetic disorders included short-read exome sequencing and short-read genome sequencing (srGS); PacBio HiFi long-read genome sequencing (HiFi-GS); variant calling for single nucleotide variants (SNV), structural variant (SV), and repeat variants; and machine-learning variant prioritization. Structured phenotypes, prioritized variants, and pedigrees were stored in PhenoTips database, with data sharing through controlled access the database of Genotypes and Phenotypes.Diagnostic rates ranged from 11% in patients with prior negative genetic testing to 34.5% in naive patients. Incorporating SVs from genome sequencing added up to 13% of new diagnoses in previously unsolved cases. HiFi-GS yielded increased discovery rate with4-fold more rare coding SVs compared with srGS. Variants and genes of unknown significance remain the most common finding (58% of nondiagnostic cases).Computational prioritization is efficient for diagnostic SNVs. Thorough identification of non-SNVs remains challenging and is partly mitigated using HiFi-GS sequencing. Importantly, community research is supported by sharing real-time data to accelerate gene validation and by providing HiFi variant (SNV/SV) resources from1000 human alleles to facilitate implementation of new sequencing platforms for rare disease diagnoses.

Purpose Vagus nerve stimulation (VNS) is an effective adjunctive therapy for drug-resistant epilepsy. Nevertheless, information is lacking regarding optimization of stimulation parameters to improve efficacy. Our study examines the safety and efficacy of rapid duty cycle VNS (OFF time ≤1.1 minute keeping duty cycle less than 50%) in pediatric cohort with intractable epilepsy. Methods Retrospective chart review of 50 patients (one to 17 years) with drug-resistant epilepsy treated with VNS between 2010 and 2015 at a single pediatric epilepsy center. Safety and tolerability data were aggregated across all patient visits to determine frequency of adverse events between differing duty cycles. We also compared seizure reduction rates for each patient at (1) last regular duty cycle visit, (2) first rapid duty cycle visit, and (3) last recorded rapid duty cycle visit. Results Rapid duty cycle was well tolerated, with no adverse events reported in 96.6% patient encounters. At the last visit before switching to rapid duty cycle 45.5% patients were showing response to VNS (seizure reduction rates ≥50%). This rate increased to 77.3% after switching to rapid duty cycle and remained at 77.4% at the last rapid duty cycle visit. Fifteen patients (34.1%) became responders to VNS after switching to rapid cycling; another 19 (43.2%) maintained their response with mostly improved seizure reduction rates. In only a few instances, responders became nonresponders after switching to rapid duty cycle. Conclusions Rapid duty cycle VNS is probably safe and well tolerated; it may also be more efficacious than regular cycling VNS in some patients. This study highlights the necessity of prospective, long-term, double-blinded studies for understanding the advantages of this VNS modality.

Purpose Generalized paroxysmal fast activity (GPFA) is a diffuse, paroxysmal, frontal predominant activity described in patients with generalized epilepsies. Studies specifically focusing on electroclinical features of typical absence seizures in children have not reported any GPFA-like features. We sought to identify GPFA in children with typical absence seizures, study its incidence, characteristic electroclinical features, and effect on their epilepsy. Methods We performed a retrospective review of electroencephalograms of children with diagnosis of absence epilepsy. A total of 173 subjects were identified. In subjects with GPFA on their electroencephalograms, GPFA characteristics were collected (i.e., predominant location, duration, amplitude, frequency, provocation factors, and if GPFA was followed by spike-wave discharges). In GPFA-positive subjects, further data sets were collected examining their demographics, duration of epilepsy, and pharmacoresponsiveness to epilepsy. Results Generalized paroxysmal fast activity was identified in 10 subjects (5.78%) with female to male ratio of 9:1. Median age of subjects was 17 years, and median duration of illness was 9.5 years. Mean maximum GPFA amplitude was 88.3 μV with posterior predominance in 9/10 subjects. Generalized paroxysmal fast activity frequency ranged between 11 and 20 Hz with duration of 1 to 4 seconds. Generalized paroxysmal fast activity was provoked with eye closure, hyperventilation, and photic stimulation. Antiseizure medications had no effect on GPFA, and epilepsy was well controlled in most subjects. Conclusions Generalized paroxysmal fast activity is uncommon in children with typical absence seizures and has medium voltage, posterior predominance, and marked female preponderance. Generalized paroxysmal fast activity is seen during both pharmacoresponsive and drug-resistant epilepsy, and is not affected by antiseizure medications. It may serve as an independent marker of lifelong epilepsy.

Status epilepticus is not rare in critically ill intensive care unit patients, but its diagnosis is often delayed or missed. The mortality for convulsive status epilepticus is dependent on the underlying aetiologies and the age of the patients and thus varies from study to study. In this context, effective molecular diagnosis in a pediatric patient with a genetically heterogeneous phenotype is essential. Homozygous or compound heterozygous variants in KPTN have been recently associated with a syndrome typified by macrocephaly, neurodevelopmental delay, and seizures. We describe a comprehensive investigation of a 9-yr-old male patient who was admitted to the intensive care unit, with focal epilepsy, static encephalopathy, autism spectrum disorder, and macrocephaly of unknown etiology, who died of status epilepticus. Clinical whole-genome sequencing revealed compound heterozygous variants in the KPTN gene. The first variant is a previously characterized 18-bp in-frame duplication (c.714_731dup) in exon 8, resulting in the protein change p.Met241_Gln246dup. The second variant, c.394 + 1G > A, affects the splice junction of exon 3. These results are consistent with a diagnosis of autosomal recessive KPTN-related disease. This is the fourth clinical report for KPTN deficiency, providing further evidence of a wider range of severity.