No abstract

Alternating hemiplegia of childhood (AHC) is a rare, severe neurodevelopmental syndrome characterized by recurrent hemiplegic episodes and distinct neurologic manifestations. AHC is usually a sporadic disorder with unknown etiology. Using exome sequencing of seven patients with AHC, and their unaffected parents, we identified de novo nonsynonymous mutations in ATP1A3 in all seven AHC patients. Subsequent sequence analysis of ATP1A3 in 98 additional patients revealed that 78% of AHC cases have a likely causal ATP1A3 mutation, including one inherited mutation in a familial case of AHC. Remarkably, six ATP1A3 mutations explain the majority of patients, including one observed in 36 patients. Unlike ATP1A3 mutations that cause rapid-onset-dystonia-parkinsonism, AHC-causing mutations revealed consistent reductions in ATPase activity without effects on protein expression. This work identifies de novo ATP1A3 mutations as the primary cause of AHC, and offers insight into disease pathophysiology by expanding the spectrum of phenotypes associated with mutations in this gene.

Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur in otherwise healthy children after common viral infections such as influenza and parainfluenza. Most ANE is sporadic and nonrecurrent (isolated ANE). However, we identified a 7 Mb interval containing a susceptibility locus (ANE1) in a family segregating recurrent ANE as an incompletely penetrant, autosomal-dominant trait. We now report that all affected individuals and obligate carriers in this family are heterozygous for a missense mutation (c.1880C-->T, p.Thr585Met) in the gene encoding the nuclear pore protein Ran Binding Protein 2 (RANBP2). To determine whether this mutation is the susceptibility allele, we screened controls and other patients with ANE who are unrelated to the index family. Patients from 9 of 15 additional kindreds with familial or recurrent ANE had the identical mutation. It arose de novo in two families and independently in several other families. Two other patients with familial ANE had different RANBP2 missense mutations that altered conserved residues. None of the three RANBP2 missense mutations were found in 19 patients with isolated ANE or in unaffected controls. We conclude that missense mutations in RANBP2 are susceptibility alleles for familial and recurrent cases of ANE.

Summary:Purpose: There is no adequate measure of healthrelated quality of life (HRQOL) specifically for children with epilepsy. The aim of this study was to develop an epilepsyspecific HRQOL questionnaire for children, covering five domains: physical function, emotional well-being, cognitive function, social function, and behavior. Second, we aimed to demonstrate the instrument's reliability and validity, and its sensitivity to differences in epilepsy severity.Methods: The subjects were guardians of children with refractory epilepsy, whose syndrome had been defined by using video-EEG monitoring. Each family completed the developed epilepsy-specific HRQOL scale for children and two standard, generic measures of HRQOL.Results: The results indicated that each of the scales of the questionnaire had good internal consistency reliability. Furthermore, each scale correlated more highly with theoretically similar scales on established, generic health measures than with theoretically dissimilar scales (construct validity). The sensitivity of the questionnaire to differences in epilepsy severity also was demonstrated. As seizure severity increased, HRQOL subscale scores decreased, independent of age, gender, age of seizure onset, and IQ. Further, there was a negative relation between the number of antiepileptic medications taken and measures of memory and language performance, which was independent of age, gender, age of seizure onset, IQ, and seizure severity.Conclusions: This study demonstrated that the developed HRQOL instrument is a reliable and valid measure and is sensitive to differences in epilepsy. These results indicate that this new instrument may be a viable medical or surgical outcome measure for children with epilepsy.

Certain mutations can cause proteins to accumulate in neurons, leading to neurodegeneration. We recently showed, however, that upregulation of a wild-type protein, Ataxin1, caused by haploinsufficiency of its repressor, the RNA-binding protein Pumilio1 (PUM1), also causes neurodegeneration in mice. We therefore searched for human patients with PUM1 mutations. We identified eleven individuals with either PUM1 deletions or de novo missense variants who suffer a developmental syndrome (Pumilio1-associated developmental disability, ataxia, and seizure; PADDAS). We also identified a milder missense mutation in a family with adult-onset ataxia with incomplete penetrance (Pumilio1-related cerebellar ataxia, PRCA). Studies in patient-derived cells revealed that the missense mutations reduced PUM1 protein levels by ∼25% in the adult-onset cases and by ∼50% in the infantile-onset cases; levels of known PUM1 targets increased accordingly. Changes in protein levels thus track with phenotypic severity, and identifying posttranscriptional modulators of protein expression should identify new candidate disease genes.

Summary:Purpose: Benign rolandic epilepsy (BRE) has an excellent prognosis for seizures, but recent research has raised concerns using cognition as an outcome measure. Methodologic problems related to recruitment bias and assessment processes are evident in previous studies. With well-defined criteria for inclusion and comprehensive assessment, the aim of this study was to define the cognitive profile of children with BRE and to assess the effect of interictal EEG activity.Methods: Patients (n = 42) were recruited from six EEG laboratories. The EEG features analyzed were spike frequency, trains, and laterality. Comprehensive neuropsychological and language assessments were conducted. Group means on cognitive measures were compared with normative means. Tests were correlated with EEG features.Results: The study demonstrated that children with BRE have normal intelligence and language ability. However, a specific pattern of difficulties in memory and phonologic awareness was found. Furthermore, a large proportion of children had disproportionate scores in these areas compared with intellectual and language ability. EEG features were minimally associated with cognitive difficulties, and no correlation was found with memory indices and tests of phonologic awareness.Conclusions: Some children with BRE have specific difficulties in memory and phonologic processing skills, not explained by interictal activity. We recommend that pediatricians ask about academic performance specifically in areas of prereading, reading, spelling, and memory. If difficulties are suspected, assessment targeting phonologic awareness and memory are recommended, as they may not be reflected in overall intellectual and language ability. Difficulties in phonologic awareness affect literacy, and memory problems affect academic performance.

This study demonstrates memory dysfunction in three common childhood epilepsy syndromes. Children with TLE had the greatest impairment, children with FLE had memory difficulties not previously reported, and children with CAE had subtle memory deficits. Qualitative differences were also evident. Longer duration of intractable epilepsy was associated with reduced memory ability. Memory function and its potential impact on academic achievement are vital considerations when managing children with epilepsy.

Summary:Purpose: To determine whether refractory epilepsy affects the health-related quality of life (HRQOL) of children with or without intellectual disability (ID), and if the presence of ID independently compromises HRQOL in children with refractory epilepsy.Methods: Subjects were parents of children with refractory epilepsy, whose syndrome had been defined using ILAE (International League Against Epilepsy) criteria and video-EEG monitoring. Children had the presence or absence of ID determined by formal neuropsychological or educational assessment. The relative effect of epilepsy on the two intellectual ability groups was determined using relevant clinical variables. Parents completed a valid epilepsy-specific HRQOL questionnaire for children, the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE), and, depending on intellectual ability level, the Child Behaviour Checklist or Developmental Behaviour Checklist.Results: Both intellectually normal children with epilepsy and children with epilepsy and ID were more likely to have psychosocial problems compared with their respective intellectual ability reference populations. The results also revealed that children with ID had reduced HRQOL compared with intellectually normal children; a result independent of epilepsy. Analysis of the relationship between epilepsy variables and HRQOL revealed that the QOLCE was the most sensitive in detecting variation in age at onset, seizure frequency, and medications taken. Conclusions:The HRQOL of children with refractory epilepsy is greatly affected, regardless of intellectual ability level. The presence of ID in children with epilepsy independently depresses HRQOL outcomes. Compared with two generic HRQOL measures, the QOLCE was the most sensitive measure to variation in epilepsy variables.