Integrated in silico and experimental assessment of disease relevance of PCDH19 missense variants.

PCDH19 is a nonclustered protocadherin molecule involved in axon bundling, synapse function, and transcriptional coregulation. Pathogenic variants in PCDH19 cause infantile-onset epilepsy known as PCDH19-clustering epilepsy or PCDH19-CE. Recent advances in DNA-sequencing technologies have led to a significant increase in the number of reported PCDH19-CE variants, many of uncertain significance. We aimed to determine the best approaches for assessing the disease relevance of missense variants in PCDH19. The application of the American College of Medical Genetics and Association for Molecular Pathology (ACMG-AMP) guidelines was only 50% accurate. Using a training set of 322 known benign or pathogenic missense variants, we identified MutPred2, MutationAssessor, and GPP as the best performing in silico tools. We generated a protein structural model of the extracellular domain and assessed 24 missense variants. We also assessed 24 variants using an in vitro reporter assay. A combination of these tools was 93% accurate in assessing known pathogenic and benign PCDH19 variants. We increased the accuracy of the ACMG-AMP classification of 45 PCDH19 variants from 50% to 94%, using these tools. In summary, we have developed a robust toolbox for the assessment of PCDH19 variant pathogenicity to improve the accuracy of PCDH19-CE variant classification.

Diagnostic yield of targeted massively parallel sequencing in children with epileptic encephalopathy.

PURPOSE: To report our institutional experience of targeted massively parallel sequencing (MPS) testing in children with epilepsy. METHOD: We retrospectively analysed the yield of targeted epileptic encephalopathy (EE) panel of 71 known EE genes in patients with epilepsy of unknown cause, who underwent clinical triage by a group of neurologists prior to the testing. We compared cost of the EE panel approach compared to traditional evaluation in patients with identified pathogenic variants. RESULTS: The yield of pathogenic variants was 28.5% (n = 30/105), highest in early onset EE <3 months including Ohtahara syndrome (52%, n = 10/19) and lowest in generalized epilepsy (0/17). Patients identified with pathogenic variants had earlier onset of seizures (median 3.6 m vs 1.1y, p < 0.001, OR 0.6/year, P < 0.02) compared to those without pathogenic variants. Pathogenic/likely pathogenic variants were found in ALDH7A1 (2), CACNA1A (1), CDKL5 (3), FOXG1 (2), GABRB3 (1), GRIN2A (1), KCNQ2 (4), KCNQ3 (1), PRRT2 (1), SCN1A (6), SCN2A (2), SCN8A (2), SYNGAP1 (1), UBE3A (2) and WWOX (1) genes. This study expands the inheritance pattern caused by KCNQ3 mutations to include an autosomal recessive severe phenotype with neonatal seizures and severe developmental delay. The average cost of etiological evaluation was less with early use of EE panel compared to the traditional investigation approach ($5990 Australian dollars (AUD) vs $13069 AUD ; p = 0.02) among the patients with identified pathogenic variants. CONCLUSION: Targeted MPS testing is a comprehensive and economical investigation that enables early genetic diagnosis in children with EE. Careful clinical triage and selection of patients with young onset EE may maximize the yield of EE panel testing.

Children's Experiences of Epilepsy: A Systematic Review of Qualitative Studies.

CONTEXT: Epilepsy is a common and severe neurologic disease associated with increased mortality, seizure-related injury, and adverse psychological and quality-of-life outcomes. OBJECTIVE: To describe the perspectives of children and adolescents with epilepsy. DATA SOURCES: Medline, Embase, PsycINFO, and CINAHL from inception to August 2015. STUDY SELECTION: Qualitative studies on children's experiences of epilepsy. DATA EXTRACTION: Results from primary studies. We used thematic synthesis to analyze the findings. RESULTS: Forty-three articles involving 951 participants aged 3 to 21 years across 21 countries were included. We identified 6 themes: loss of bodily control (being overtaken, susceptibility to physical harm, fragility of the brain, alertness to mortality, incapacitating fatigue), loss of privacy (declarative disease, humiliating involuntary function, unwanted special attention, social embarrassment of medicine-taking), inescapable inferiority and discrimination (vulnerability to prejudice, inability to achieve academically, consciousness of abnormality, parental shame, limiting social freedom), therapeutic burden and futility (unattainable closure, financial burden, overwhelming life disruption, exhaustion from trialing therapies, insurmountable side effects, awaiting a fabled remission), navigating health care (empowerment through information, valuing empathetic and responsive care, unexpected necessity of transition, fragmented and inconsistent care), and recontextualizing to regain normality (distinguishing disease from identity, taking ownership, gaining perspective and maturity, social and spiritual connectedness). LIMITATIONS: Non-English articles were excluded. CONCLUSIONS: Children with epilepsy experience vulnerability, disempowerment, and discrimination. Repeated treatment failure can raise doubt about the attainment of remission. Addressing stigma, future independence, and fear of death may improve the overall well-being of children with epilepsy.