A study of incidence, causative factors, symptoms, and prognosis in epilepsy with onset in the first two years of life

Background: The motivation to start this thesis work came from the meetings with infants just having presented with epileptic seizures and from speaking to their parents. I found two issues to be particularly urgent. The first was to give the parents, and myself, an overall map of the situation. A map that had to address questions like: What are the implications of the seizures in this specific infant? What should be done next? What are the alternative future scenarios and their respective probabilities? When the population-based studies in this thesis started, the knowledge-base to answer such questions was poor, studies were few and the numbers of infants studied were small. The second issue concerned the cause of disease in the individual child. For decades the cause of epilepsy has been revealed in only a minority of cases. Especially in severe disease, like drug-resistant epilepsy, not knowing the cause places a heavy psychological burden on the family. In addition, treatment will be symptomatic, not directed at the (unknown) disease mechanisms and often ineffective. Methods: Two circumstances offered the opportunity to deal with these issues. The Stockholm Incidence Registry of Epilepsy (SIRE) registered all new cases of epilepsy in the Northern Stockholm region from September 2001 and onwards. All children with epilepsy in this area are managed at the Karolinska University Hospital. This provides a population-based perspective, which is the best way to study a disease and all aspects of it including etiology, clinical characteristics, and outcome. The other favorable condition was the development of genetic diagnostics, in particular massively parallel DNA sequencing, where Science for Life Laboratory was very early to establish whole exome and whole genome sequencing for both research and clinical healthcare purposes, in a close collaboration between the Clinical Genomic facility and the Karolinska University Laboratory. Results: The population-based studies of this thesis include 116 children with onset of epilepsy during the first 2 years of life. A majority of the cases could be assigned to an epilepsy syndrome and have the etiology revealed. Massively parallel sequencing contributed substantially to reveal genetic etiologies. About half of the children were diagnosed with intellectual disability and half of the cases were in seizure remission for 2 years or longer at age 7 years. Type of etiology is the main predictor of outcome. Two new disease genes, closely related and both with a central role in neuronal inhibition-excitation, were uncovered and described as part of the thesis. Significance: Together with a few other recent population-based studies, this thesis contributes to a firm knowledge-base when managing infants with epilepsy and counselling their parents. The important role of massively parallel DNA sequencing in revealing monogenic etiologies in early onset epilepsy has been clearly shown. In addition to enabling genetic counselling and prenatal diagnostics, the inclusion of genetic diagnostics in the work-up of children with epilepsy, will henceforth further the development of more effective and even curative precision medicine treatments of epilepsy

Feedback Control of Thermoacoustic Instability Using Acoustic Actuator

Thermoacoustic instability is a phenomenom that appears in several technical applications, for instance rocket and jet engines, gas turbines, waste generators and industrial burners where it can cause heavy damage to the systems. As with most instabilities, they are undesired and this thesis' purpose is to identify and control a Rijke tube process (which has been used to stimulate the thermoacoustic instabilities) with the aid of microphones and a loudspeaker. A major part of the work has been done on setting up such a process, considering for instance the necessary high sample rates and make future experiments possible and also to show that the process can be controlled with very simple means in a very simple environment

Case report: Fatal outcome of pyridoxine-dependent epilepsy presenting as respiratory distress followed by a circulatory collapse

Pyridoxine-dependent epilepsy is a rare autosomal recessive disease usually associated with neonatal seizures that do not respond to common antiseizure medications but are controlled by pyridoxine administration. Because the symptoms can mimic common neonatal disorders, the diagnosis can be initially missed or delayed. We report a fatal case of a boy who was initially diagnosed with respiratory distress, birth asphyxia, and persistent pulmonary hypertension and whose condition rapidly deteriorated during the first day of life

An investigation of the validity of course-based online assessment methods: The role of computer-related attitudes and assessment mode preferences

The use of e-assessment methods raises important concerns regarding the reliability and validity of these methods. Potential threats to validity include mode effects and the possible influence of computer-related attitudes. While numerous studies have now investigated the validity of online assessments in non-course-based contexts, few studies have addressed this issue in an educational context. The present study helps fill this research gap by investigating whether university students' computer-related attitudes and assessment mode preferences were related to performance on a course-based online assessment task. Overall, students' attitudes and preferences bore no greater relationships to performance on the online than offline module assessment tasks. This provides support for the validity of course-based online assessment methods and should help alleviate educators' concerns and encourage more widespread adoption of these methods, helping address the issue of their slow uptake to date. Suggestions for follow-up studies to corroborate and extend the current findings are offered

Epilepsy due to PNPO mutations: genotype, environment and treatment affect presentation and outcome

Mutations in PNPO are a known cause of neonatal onset seizures that are resistant to pyridoxine but responsive to pyridoxal phosphate (PLP). Mills etal. show that PNPO mutations can also cause neonatal onset seizures that respond to pyridoxine but worsen with PLP, as well as PLP-responsive infantile spasm

An LC-MS/MS-Based Method for the Quantification of Pyridox(am)ine 5'-Phosphate Oxidase Activity in Dried Blood Spots from Patients with Epilepsy

We report the development of a rapid, simple, and robust LC-MS/MS-based enzyme assay using dried blood spots (DBS) for the diagnosis of pyridox(am)ine 5'-phosphate oxidase (PNPO) deficiency (OMIM 610090). PNPO deficiency leads to potentially fatal early infantile epileptic encephalopathy, severe developmental delay, and other features of neurological dysfunction. However, upon prompt treatment with high doses of vitamin B6, affected patients can have a normal developmental outcome. Prognosis of these patients is therefore reliant upon a rapid diagnosis. PNPO activity was quantified by measuring pyridoxal 5'-phosphate (PLP) concentrations in a DBS before and after a 30 min incubation with pyridoxine 5'-phosphate (PNP). Samples from 18 PNPO deficient patients (1 day-25 years), 13 children with other seizure disorders receiving B6 supplementation (1 month-16 years), and 37 child hospital controls (5 days-15 years) were analyzed. DBS from the PNPO-deficient samples showed enzyme activity levels lower than all samples from these two other groups as well as seven adult controls; no false positives or negatives were identified. The method was fully validated and is suitable for translation into the clinical diagnostic arena

Genetic, Phenotypic, and Interferon Biomarker Status in ADAR1-Related Neurological Disease

International audienceWe investigated the genetic, phenotypic, and interferon status of 46 patients from 37 families with neurological disease due to mutations in ADAR1. The clinicoradiological phenotype encompassed a spectrum of Aicardi–Goutières syndrome, isolated bilateral striatal necrosis, spastic paraparesis with normal neuroimaging, a progressive spastic dystonic motor disorder, and adult-onset psychological difficulties with intracranial calcification. Homozygous missense mutations were recorded in five families. We observed a p.Pro193Ala variant in the heterozygous state in 22 of 23 families with compound heterozygous mutations. We also ascertained 11 cases from nine families with a p.Gly1007Arg dominant-negative mutation, which occurred de novo in four patients, and was inherited in three families in association with marked phenotypic variability. In 50 of 52 samples from 34 patients, we identified a marked upregulation of type I interferon-stimulated gene transcripts in peripheral blood, with a median interferon score of 16.99 (interquartile range [IQR]: 10.64–25.71) compared with controls (median: 0.93, IQR: 0.57–1.30). Thus, mutations in ADAR1 are associated with a variety of clinically distinct neurological phenotypes presenting from early infancy to adulthood, inherited either as an autosomal recessive or dominant trait. Testing for an interferon signature in blood represents a useful biomarker in this context

Epilepsy due to PNPO mutations: genotype, environment and treatment affect presentation and outcome.

The first described patients with pyridox(am)ine 5'-phosphate oxidase deficiency all had neonatal onset seizures that did not respond to treatment with pyridoxine but responded to treatment with pyridoxal 5'-phosphate. Our data suggest, however, that the clinical spectrum of pyridox(am)ine 5'-phosphate oxidase deficiency is much broader than has been reported in the literature. Sequencing of the PNPO gene was undertaken for a cohort of 82 individuals who had shown a reduction in frequency and severity of seizures in response to pyridoxine or pyridoxal 5'-phosphate. Novel sequence changes were studied using a new cell-free expression system and a mass spectrometry-based assay for pyridoxamine phosphate oxidase. Three groups of patients with PNPO mutations that had reduced enzyme activity were identified: (i) patients with neonatal onset seizures responding to pyridoxal 5'-phosphate (n = 6); (ii) a patient with infantile spasms (onset 5 months) responsive to pyridoxal 5'-phosphate (n = 1); and (iii) patients with seizures starting under 3 months of age responding to pyridoxine (n = 8). Data suggest that certain genotypes (R225H/C and D33V) are more likely to result in seizures that to respond to treatment with pyridoxine. Other mutations seem to be associated with infertility, miscarriage and prematurity. However, the situation is clearly complex with the same combination of mutations being seen in patients who responded and did not respond to pyridoxine. It is possible that pyridoxine responsiveness in PNPO deficiency is affected by prematurity and age at the time of the therapeutic trial. Other additional factors that are likely to influence treatment response and outcome include riboflavin status and how well the foetus has been supplied with vitamin B6 by the mother. For some patients there was a worsening of symptoms on changing from pyridoxine to pyridoxal 5'-phosphate. Many of the mutations in PNPO affected residues involved in binding flavin mononucleotide or pyridoxal 5'-phosphate and many of them showed residual enzyme activity. One sequence change (R116Q), predicted to affect flavin mononucleotide binding and binding of the two PNPO dimers, and with high residual activity was found in Groups (ii) and (iii). This sequence change has been reported in the 1000 Genomes project suggesting it could be a polymorphism but alternatively it could be a common mutation, perhaps responsible for the susceptibility locus for genetic generalized epilepsy on 17q21.32 (close to rs72823592). We believe the reduction in PNPO activity and B6-responsive epilepsy in the patients reported here indicates that it contributes to the pathogenesis of epilepsy