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.

A full list of authors and affiliations appears at the end of the paper.Purpose: To define the phenotypic and mutational spectrum of epilepsies related to DEPDC5, NPRL2 and NPRL3 genes encoding the GATOR1 complex, a negative regulator of the mTORC1 pathway Methods:We analyzed clinical and genetic data of 73 novel probands (familial and sporadic) with epilepsy-related variants in GATOR1-encoding genes and proposed new guidelines for clinical interpretation of GATOR1 variants.Results: The GATOR1 seizure phenotype consisted mostly in focal seizures (e.g., hypermotor or frontal lobe seizures in 50%), with a mean age at onset of 4.4 years, often sleep-related and drugresistant (54%), and associated with focal cortical dysplasia (20%). Infantile spasms were reported in 10% of the probands. Sudden unexpected death in epilepsy (SUDEP) occurred in 10% of the families. Novel classification framework of all 140 epilepsy-related GATOR1 variants (including the variants of this study) revealed that 68% are loss-of-function pathogenic, 14% are likely pathogenic, 15% are variants of uncertain significance and 3% are likely benign.Conclusion: Our data emphasize the increasingly important role of GATOR1 genes in the pathogenesis of focal epilepsies (>180 probands to date). The GATOR1 phenotypic spectrum ranges from sporadic early-onset epilepsies with cognitive impairment comorbidities to familial focal epilepsies, and SUDEP.Genetics in Medicine (2018) https://doi

De novo STXBP1 mutations are among the most frequent causes of epilepsy and encephalopathy. Most patients have severe to profound ID with little correlation among seizure onset, seizure severity, and the degree of ID. Accordingly, we hypothesize that seizure severity and ID present 2 independent dimensions of the STXBP1-E phenotype. STXBP1-E may be conceptualized as a complex neurodevelopmental disorder rather than a primary epileptic encephalopathy.

AIM Determining inclusion/exclusion criteria for cerebral palsy (CP) surveillance is challenging. The aims of this paper were to (1) define inclusion/exclusion criteria that have been adopted uniformly by surveillance programmes and identify where consensus is still elusive, and (2) provide an updated list of the consensus concerning CP inclusion/exclusion when a syndrome/disorder is diagnosed.METHOD Data were drawn from an international survey of CP registers, the New South Wales CP Register (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003), the Western Australian CP Register (1975Register ( -2008, and the Surveillance of CP in Europe (SCPE; 1976-1998). An expert panel used a consensus building technique, which utilized the SCPE 'decision tree' and the original 'What constitutes cerebral palsy?' paper as frameworks.RESULTS CP surveillance programmes agree on key clinical criteria pertaining to the type, severity, and origin of motor disorder in CP. Further work is warranted to reach agreement for (1) minimum age of survival and maximum age of postneonatal brain injury, and (2) metabolic disorders with highly variable clinical courses/responses to treatment. One hundred and ninety-seven syndromes/disorders were reviewed and advice on their inclusion/ exclusion is provided. INTERPRETATIONWhat constitutes CP will continue to evolve as diagnostics improve.Surveillance programmes throughout the world are committed to addressing their differences regarding inclusion/exclusion criteria for the umbrella term CP.Advances and changes in diagnostic modalities and medical technology since our 1998 publication 'What constitutes cerebral palsy?' 1 have led to requests to revise the paper. Since 1998 we have seen an increase in the number of CP surveillance programmes internationally and their desire for collaboration led to the first World CP Register Day in 2009.2 Inclusion/exclusion criteria in CP surveillance were key points discussed. It was acknowledged by participants that whilst each group must meet the specific needs of their own individual surveillance programme, it is advantageous to have consensus across programmes regarding core inclusion/exclusion criteria. Consensus in criteria provides opportunities to pool data across registers, increase power for research, monitor trends over time between and across regions, and to evaluate new population level interventions such as magnesium sulphate 3 and cooling. 4 Similarly, homogeneity of inclusion/exclusion criteria is advantageous for researchers using registers as a sampling frame for multicentre trials. This article seeks to (1) define inclusion/exclusion criteria that have been adopted uniformly by surveillance programmes and to illuminate areas where consensus about criteria could not be reached between surveillance programmes, and (2) provide an updated list of the consensus concerning the inclusion or exclusion of CP when a syndrome or disorder is diagnosed. the original 1998 paper 1 or identified in potential registrants of the New South Wales ...

Aims: To determine the proportion of children admitted with difficult to treat paroxysmal events to a tertiary epilepsy centre who did not have epilepsy. Methods: In an observational retrospective study, all case notes of 223 children admitted in 1997 were examined. The referral was made from the local paediatric department in 51% of cases, other departments in 27%, and from general or specialist practitioners in 22%. Doubt regarding the diagnosis of epilepsy was expressed in the referral note in 17%. On admission, 86% were on antiepileptic drug treatment. During admission all children were subjected to a comprehensive intensive observation and 62% had EEG monitoring. Results: In total, 39% (87/223) were found not to have epilepsy. In 30% of children (55/184) referred without any doubts about the epilepsy diagnosis, the diagnosis was disproved. Of the 159 children admitted for the first time, 75 (47%) were discharged with a diagnosis of non-epileptic seizures. Of 125 children admitted for the first time with no doubts about the diagnosis of epilepsy, 44 (35%) did not have epilepsy. Staring episodes were the most frequently encountered non-epileptic paroxysmal event. Psychogenic non-epileptic seizures were found in 12 children. A total of 34 (15%) had their medication tapered off; a further 22 (10%) had tapered off medication before admission. Conclusion: The present study supports the view that misdiagnosis of epilepsy is common. The treating physician should be cautious in diagnosis, especially of staring episodes. A diagnostic re-evaluation should be undertaken in difficult cases with continuing paroxysmal events in order to avoid unnecessary drug treatment and restrictions on the child's lifestyle.

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The late-infantile form of neuronal ceroid lipofuscinosis (LINCL) is a progressive and ultimately fatal neurodegenerative disease of childhood. The defective gene in this hereditary disorder, CLN2, encodes a recently identified lysosomal pepstatin-insensitive acid protease. To better understand the molecular pathology of LINCL, we conducted a genetic survey of CLN2 in 74 LINCL families. In 14 patients, CLN2 protease activities were normal and no mutations were identified, suggesting other forms of NCL. Both pathogenic alleles were identified in 57 of the other 60 LINCL families studied. In total, 24 mutations were associated with LINCL, comprising six splice-junction mutations, 11 missense mutations, 3 nonsense mutations, 3 small deletions, and 1 single-nucleotide insertion. Two mutations were particularly common: an intronic G-->C transversion in the invariant AG of a 3' splice junction, found in 38 of 115 alleles, and a C-->T transition in 32 of 115 alleles, which prematurely terminates translation at amino acid 208 of 563. An Arg-->His substitution was identified, which was associated with a late age at onset and protracted clinical phenotype, in a number of other patients originally diagnosed with juvenile NCL.