Solving the Etiology of Developmental and Epileptic Encephalopathy with Spike-Wave Activation in Sleep (D/EE-SWAS).

OBJECTIVE: To understand the etiological landscape and phenotypic differences between 2 developmental and epileptic encephalopathy (DEE) syndromes: DEE with spike-wave activation in sleep (DEE-SWAS) and epileptic encephalopathy with spike-wave activation in sleep (EE-SWAS). METHODS: All patients fulfilled International League Against Epilepsy (ILAE) DEE-SWAS or EE-SWAS criteria with a Core cohort (n = 91) drawn from our Epilepsy Genetics research program, together with 10 etiologically solved patients referred by collaborators in the Expanded cohort (n = 101). Detailed phenotyping and analysis of molecular genetic results were performed. We compared the phenotypic features of individuals with DEE-SWAS and EE-SWAS. Brain-specific gene co-expression analysis was performed for D/EE-SWAS genes. RESULTS: We identified the etiology in 42/91 (46%) patients in our Core cohort, including 29/44 (66%) with DEE-SWAS and 13/47 (28%) with EE-SWAS. A genetic etiology was identified in 31/91 (34%). D/EE-SWAS genes were highly co-expressed in brain, highlighting the importance of channelopathies and transcriptional regulators. Structural etiologies were found in 12/91 (13%) individuals. We identified 10 novel D/EE-SWAS genes with a range of functions: ATP1A2, CACNA1A, FOXP1, GRIN1, KCNMA1, KCNQ3, PPFIA3, PUF60, SETD1B, and ZBTB18, and 2 novel copy number variants, 17p11.2 duplication and 5q22 deletion. Although developmental regression patterns were similar in both syndromes, DEE-SWAS was associated with a longer duration of epilepsy and poorer intellectual outcome than EE-SWAS. INTERPRETATION: DEE-SWAS and EE-SWAS have highly heterogeneous genetic and structural etiologies. Phenotypic analysis highlights valuable clinical differences between DEE-SWAS and EE-SWAS which inform clinical care and prognostic counseling. Our etiological findings pave the way for the development of precision therapies. ANN NEUROL 2024;96:932-943.

TUBB3 Arg262His causes a recognizable syndrome including CFEOM3, facial palsy, joint contractures, and early-onset peripheral neuropathy.

Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations. Here, we report fourteen individuals from thirteen unrelated families, each of whom harbors the identical NM_006086.4 (TUBB3):c.785G>A (p.Arg262His) variant resulting in a phenotype we refer to as the TUBB3 R262H syndrome. The affected individuals present at birth with ptosis, ophthalmoplegia, exotropia, facial weakness, facial dysmorphisms, and, in most cases, distal congenital joint contractures, and subsequently develop intellectual disabilities, gait disorders with proximal joint contractures, Kallmann syndrome (hypogonadotropic hypogonadism and anosmia), and a progressive peripheral neuropathy during the first decade of life. Subsets may also have vocal cord paralysis, auditory dysfunction, cyclic vomiting, and/or tachycardia at rest. All fourteen subjects share a recognizable set of brain malformations, including hypoplasia of the corpus callosum and anterior commissure, basal ganglia malformations, absent olfactory bulbs and sulci, and subtle cerebellar malformations. While similar, individuals with the TUBB3 R262H syndrome can be distinguished from individuals with the TUBB3 E410K syndrome by the presence of congenital and acquired joint contractures, an earlier onset peripheral neuropathy, impaired gait, and basal ganglia malformations.

Biallelic variants in PCDHGC4 cause a novel neurodevelopmental syndrome with progressive microcephaly, seizures, and joint anomalies.

PURPOSE: We aimed to define a novel autosomal recessive neurodevelopmental disorder, characterize its clinical features, and identify the underlying genetic cause for this condition. METHODS: We performed a detailed clinical characterization of 19 individuals from nine unrelated, consanguineous families with a neurodevelopmental disorder. We used genome/exome sequencing approaches, linkage and cosegregation analyses to identify disease-causing variants, and we performed three-dimensional molecular in silico analysis to predict causality of variants where applicable. RESULTS: In all affected individuals who presented with a neurodevelopmental syndrome with progressive microcephaly, seizures, and intellectual disability we identified biallelic disease-causing variants in Protocadherin-gamma-C4 (PCDHGC4). Five variants were predicted to induce premature protein truncation leading to a loss of PCDHGC4 function. The three detected missense variants were located in extracellular cadherin (EC) domains EC5 and EC6 of PCDHGC4, and in silico analysis of the affected residues showed that two of these substitutions were predicted to influence the Ca2+-binding affinity, which is essential for multimerization of the protein, whereas the third missense variant directly influenced the cis-dimerization interface of PCDHGC4. CONCLUSION: We show that biallelic variants in PCDHGC4 are causing a novel autosomal recessive neurodevelopmental disorder and link PCDHGC4 as a member of the clustered PCDH family to a Mendelian disorder in humans.

Deficiencies in vesicular transport mediated by TRAPPC4 are associated with severe syndromic intellectual disability.

The conserved transport protein particle (TRAPP) complexes regulate key trafficking events and are required for autophagy. TRAPPC4, like its yeast Trs23 orthologue, is a core component of the TRAPP complexes and one of the essential subunits for guanine nucleotide exchange factor activity for Rab1 GTPase. Pathogenic variants in specific TRAPP subunits are associated with neurological disorders. We undertook exome sequencing in three unrelated families of Caucasian, Turkish and French-Canadian ethnicities with seven affected children that showed features of early-onset seizures, developmental delay, microcephaly, sensorineural deafness, spastic quadriparesis and progressive cortical and cerebellar atrophy in an effort to determine the genetic aetiology underlying neurodevelopmental disorders. All seven affected subjects shared the same identical rare, homozygous, potentially pathogenic variant in a non-canonical, well-conserved splice site within TRAPPC4 (hg19:chr11:g.118890966A>G; TRAPPC4: NM_016146.5; c.454+3A>G). Single nucleotide polymorphism array analysis revealed there was no haplotype shared between the tested Turkish and Caucasian families suggestive of a variant hotspot region rather than a founder effect. In silico analysis predicted the variant to cause aberrant splicing. Consistent with this, experimental evidence showed both a reduction in full-length transcript levels and an increase in levels of a shorter transcript missing exon 3, suggestive of an incompletely penetrant splice defect. TRAPPC4 protein levels were significantly reduced whilst levels of other TRAPP complex subunits remained unaffected. Native polyacrylamide gel electrophoresis and size exclusion chromatography demonstrated a defect in TRAPP complex assembly and/or stability. Intracellular trafficking through the Golgi using the marker protein VSVG-GFP-ts045 demonstrated significantly delayed entry into and exit from the Golgi in fibroblasts derived from one of the affected subjects. Lentiviral expression of wild-type TRAPPC4 in these fibroblasts restored trafficking, suggesting that the trafficking defect was due to reduced TRAPPC4 levels. Consistent with the recent association of the TRAPP complex with autophagy, we found that the fibroblasts had a basal autophagy defect and a delay in autophagic flux, possibly due to unsealed autophagosomes. These results were validated using a yeast trs23 temperature sensitive variant that exhibits constitutive and stress-induced autophagic defects at permissive temperature and a secretory defect at restrictive temperature. In summary we provide strong evidence for pathogenicity of this variant in a member of the core TRAPP subunit, TRAPPC4 that associates with vesicular trafficking and autophagy defects. This is the first report of a TRAPPC4 variant, and our findings add to the growing number of TRAPP-associated neurological disorders.

Auditory neuropathy in Brown-Vialetto-Van Laere syndrome due to riboflavin transporter RFVT2 deficiency.

AIM: Mutations in the genes encoding the riboflavin transporters RFVT2 and RFVT3 have been identified in Brown-Vialetto-Van Laere syndrome, a neurodegenerative disorder characterized by hearing loss and pontobulbar palsy. Treatment with riboflavin has been shown to benefit individuals with the phenotype of RFVT2 deficiency. Understanding the characteristics of hearing loss in riboflavin transporter deficiency would enable early diagnosis and therapy. METHOD: We performed hearing assessments in seven children (from four families) with RFVT2 deficiency and reviewed results from previous assessments. Assessments were repeated after 12 months and 24 months of riboflavin therapy and after cochlear implantation in one individual. RESULTS: Hearing loss in these individuals was due to auditory neuropathy spectrum disorder (ANSD). Hearing loss was identified between 3 years and 8 years of age and progressed rapidly. Hearing aids were not beneficial. Riboflavin therapy resulted in improvement of hearing thresholds during the first year of treatment in those with recent-onset hearing loss. Cochlear implantation resulted in a significant improvement in speech perception in one individual. INTERPRETATION: Riboflavin transporter deficiency should be considered in all children presenting with an auditory neuropathy. Speech perception in children with ANSD due to RFVT2 deficiency may be significantly improved by cochlear implantation.

Treatable childhood neuronopathy caused by mutations in riboflavin transporter RFVT2.

Childhood onset motor neuron diseases or neuronopathies are a clinically heterogeneous group of disorders. A particularly severe subgroup first described in 1894, and subsequently called Brown-Vialetto-Van Laere syndrome, is characterized by progressive pontobulbar palsy, sensorineural hearing loss and respiratory insufficiency. There has been no treatment for this progressive neurodegenerative disorder, which leads to respiratory failure and usually death during childhood. We recently reported the identification of SLC52A2, encoding riboflavin transporter RFVT2, as a new causative gene for Brown-Vialetto-Van Laere syndrome. We used both exome and Sanger sequencing to identify SLC52A2 mutations in patients presenting with cranial neuropathies and sensorimotor neuropathy with or without respiratory insufficiency. We undertook clinical, neurophysiological and biochemical characterization of patients with mutations in SLC52A2, functionally analysed the most prevalent mutations and initiated a regimen of high-dose oral riboflavin. We identified 18 patients from 13 families with compound heterozygous or homozygous mutations in SLC52A2. Affected individuals share a core phenotype of rapidly progressive axonal sensorimotor neuropathy (manifesting with sensory ataxia, severe weakness of the upper limbs and axial muscles with distinctly preserved strength of the lower limbs), hearing loss, optic atrophy and respiratory insufficiency. We demonstrate that SLC52A2 mutations cause reduced riboflavin uptake and reduced riboflavin transporter protein expression, and we report the response to high-dose oral riboflavin therapy in patients with SLC52A2 mutations, including significant and sustained clinical and biochemical improvements in two patients and preliminary clinical response data in 13 patients with associated biochemical improvements in 10 patients. The clinical and biochemical responses of this SLC52A2-specific cohort suggest that riboflavin supplementation can ameliorate the progression of this neurodegenerative condition, particularly when initiated soon after the onset of symptoms.

CSF neopterin, quinolinic acid and kynurenine/tryptophan ratio are biomarkers of active neuroinflammation.

BACKGROUND: Defining the presence of acute and chronic brain inflammation remains a challenge to clinicians due to the heterogeneity of clinical presentations and aetiologies. However, defining the presence of neuroinflammation, and monitoring the effects of therapy is important given its reversible and potentially damaging nature. We investigated the utility of CSF metabolites in the diagnosis of primary neuroinflammatory disorders such as encephalitis and explored the potential pathogenic role of inflammation in epilepsy. METHODS: Cerebrospinal fluid (CSF) collected from 341 paediatric patients (169 males, median age 5.8 years, range 0.1-17.1) were examined. The patients were separated into a primary inflammatory disorder group (n = 90) and epilepsy group (n = 80), who were compared with three control groups including neurogenetic and structural (n = 76), neurodevelopmental disorders, psychiatric and functional neurological disorders (n = 63), and headache (n = 32). FINDINGS: There were statistically significant increases of CSF neopterin, kynurenine, quinolinic acid and kynurenine/tryptophan ratio (KYN/TRP) in the inflammation group compared to all control groups (all p < 0.0003). As biomarkers, at thresholds with 95% specificity, CSF neopterin had the best sensitivity for defining neuroinflammation (82%, CI 73-89), then quinolinic acid (57%, CI 47-67), KYN/TRP ratio (47%, CI 36-56) and kynurenine (37%, CI 28-48). CSF pleocytosis had sensitivity of 53%, CI 42-64). The area under the receiver operating characteristic curve (ROC AUC) of CSF neopterin (94.4% CI 91.0-97.7%) was superior to that of CSF pleocytosis (84.9% CI 79.5-90.4%) (p = 0.005). CSF kynurenic acid/kynurenine ratio (KYNA/KYN) was statistically decreased in the epilepsy group compared to all control groups (all p ≤ 0.0003), which was evident in most epilepsy subgroups. INTERPRETATION: Here we show that CSF neopterin, kynurenine, quinolinic acid and KYN/TRP are useful diagnostic and monitoring biomarkers of neuroinflammation. These findings provide biological insights into the role of inflammatory metabolism in neurological disorders and provide diagnostic and therapeutic opportunities for improved management of neurological diseases. FUNDING: Financial support for the study was granted by Dale NHMRC Investigator grant APP1193648, University of Sydney, Petre Foundation, Cerebral Palsy Alliance and Department of Biochemistry at the Children's Hospital at Westmead. Prof Guillemin is funded by NHMRC Investigator grant APP 1176660 and Macquarie University.

Accelerated long-term forgetting in children with idiopathic generalized epilepsy.

PURPOSE: The rapid forgetting of information over long (but not short) delays (accelerated long-term forgetting [ALF]) has been associated with temporal lobe epilepsy but not idiopathic generalized epilepsy (IGE). Long-term memory formation (consolidation) is thought to demand an interaction between medial temporal and neocortical networks, which could be disrupted by epilepsy/seizures themselves. The present study investigates whether ALF is present in children with IGE and whether it relates to epilepsy severity. METHODS: Sixty-one children (20 with IGE and 41 healthy controls [HC]) of comparable age, sex, and parental socioeconomic status completed neuropsychological tests, including a measure of verbal learning and recall after, short (30-min) and long (7-day) delays, and recognition. Epilepsy severity was rated by treating neurologists. KEY FINDINGS: A two-way repeated measures analysis of covariance (ANCOVA) found a significant Group x Delay interaction; the children with IGE recalled (and recognized) significantly fewer words after a long, but not short (2- and 30-min) delay relative to the HC children. Moreover, greater epilepsy severity was associated with poorer recognition. SIGNIFICANCE: This study demonstrates, to our knowledge for the first time, that children with IGE present with ALF, which is related to epilepsy severity. These findings support the notion that epilepsy/seizures themselves may disrupt long-term memory consolidation, which interferes with day-to-day functioning of children with IGE.

Familial PRRT2 mutation with heterogeneous paroxysmal disorders including paroxysmal torticollis and hemiplegic migraine.

PRRT2 is the gene recently associated with paroxysmal kinesigenic dyskinesia (PKD), benign familial infantile epilepsy, and choreoathetosis infantile convulsions. We report four family members with PRRT2 mutations who had heterogeneous paroxysmal disorders. The index patient had transient infantile paroxysmal torticollis, then benign infantile epilepsy that responded to carbamazepine. The index patient's father had PKD and migraine with aphasia, and his two brothers had hemiplegic migraine with onset in childhood. All four family members had the same PRRT2 c.649dupC mutation. We conclude that heterogeneous paroxysmal disorders are associated with PRRT2 mutations and include paroxysmal torticollis and hemiplegic migraine. We propose that PRRT2 is a new gene for hemiplegic migraine.

Decreased cerebrospinal fluid kynurenic acid in epileptic spasms: A biomarker of response to corticosteroids.

BACKGROUND: Epileptic (previously infantile) spasms is the most common epileptic encephalopathy occurring during infancy and is frequently associated with abnormal neurodevelopmental outcomes. Epileptic spasms have a diverse range of known (genetic, structural) and unknown aetiologies. High dose corticosteroid treatment for 4 weeks often induces remission of spasms, although the mechanism of action of corticosteroid is unclear. Animal models of epileptic spasms have shown decreased brain kynurenic acid, which is increased after treatment with the ketogenic diet. We quantified kynurenine pathway metabolites in the cerebrospinal fluid (CSF) of infants with epileptic spasms and explored clinical correlations. METHODS: A panel of nine metabolites in the kynurenine pathway (tryptophan, kynurenine, kynurenic acid, 3-hydroxykynurenine, xanthurenic acid, anthranilic acid, 3-hydroxyanthranilic acid, quinolinic acid, and picolinic acid) were measured using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). CSF collected from paediatric patients less than 3 years of age with epileptic spasms (n=34, 19 males, mean age 0.85, median 0.6, range 0.3-3 yrs) were compared with other epilepsy syndromes (n=26, 9 males, mean age 1.44, median 1.45, range 0.3-3 yrs), other non-inflammatory neurological diseases (OND) (n=29, 18 males, mean age 1.47, median 1.6, range 0.1-2.9 yrs) and inflammatory neurological controls (n=12, 4 males, mean age 1.80, median 1.80, range 0.8-2.5 yrs). FINDINGS: There was a statistically significant decrease of CSF kynurenic acid in patients with epileptic spasms compared to OND (p<0.0001). In addition, the kynurenic acid/kynurenine (KYNA/KYN) ratio was lower in the epileptic spasms subgroup compared to OND (p<0.0001). Epileptic spasms patients who were steroid responders or partial steroid responders had lower KYNA/KYN ratio compared to patients who were refractory to steroids (p<0.005, p<0.05 respectively). INTERPRETATION: This study demonstrates decreased CSF kynurenic acid and KYNA/KYN in epileptic spasms, which may also represent a biomarker for steroid responsiveness. Given the anti-inflammatory and neuroprotective properties of kynurenic acid, further therapeutics able to increase kynurenic acid should be explored. FUNDING: Financial support for the study was granted by Dale NHMRC Investigator grant APP1193648, Petre Foundation, Cerebral Palsy Alliance and Department of Biochemistry at the Children's Hospital at Westmead. Prof Guillemin is funded by NHMRC Investigator grant APP1176660 and Macquarie University.

Yield of comparative genomic hybridization microarray in pediatric neurology practice.

OBJECTIVE: The present study investigated the diagnostic yield of array comparative genomic hybridization (aCGH) in a large cohort of children with diverse neurologic disorders as seen in child neurology practice to test whether pathogenic copy number variants (CNVs) were more likely to be detected in specific neurologic phenotypes. METHODS: A retrospective cross-sectional analysis was performed on 555 children in whom a genetic etiology was suspected and who underwent whole-genome aCGH testing between 2006 and 2012. Neurologic phenotyping was performed using hospital medical records. An assessment of pathogenicity was made for each CNV, based on recent developments in the literature. RESULTS: Forty-seven patients were found to carry a pathogenic CNV, giving an overall diagnostic yield of 8.59%. Certain phenotypes predicted for the presence of a pathogenic CNV, including developmental delay (odds ratio [OR] 3.69 [1.30-10.51]), cortical visual impairment (OR 2.73 [1.18-6.28]), dysmorphism (OR 2.75 [1.38-5.50]), and microcephaly (OR 2.16 [1.01-4.61]). The combination of developmental delay/intellectual disability with dysmorphism and abnormal head circumference was also predictive for a pathogenic CNV (OR 2.86 [1.02-8.00]). For every additional clinical feature, there was an increased likelihood of detecting a pathogenic CNV (OR 1.18 [1.01-1.38]). CONCLUSIONS: The use of aCGH led to a pathogenic finding in 8.59% of patients. The results support the use of aCGH as a first tier investigation in children with diverse neurologic disorders, although whole-genome sequencing may replace aCGH as the detection method in the future. In particular, the yield was increased in children with developmental delay, dysmorphism, cortical visual impairment, and microcephaly.

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.

Pathophysiology of motor dysfunction in a childhood motor neuron disease caused by mutations in the riboflavin transporter.

OBJECTIVE: Brown-Vialetto-Van Laere (BVVL) syndrome is a progressive motor and sensory neuronopathy secondary to mutations in SLC52A2 encoding the riboflavin transporter type 2 (RFVT2). The phenotype is characterized by early childhood onset hearing loss and sensory ataxia followed by progressive upper limb weakness, optic atrophy, bulbar weakness and respiratory failure. To gain further insight into disease pathophysiology and response to riboflavin supplementation, the present study investigated whether axonal ion channel or membrane abnormalities were a feature of BVVL. METHODS: Axonal excitability studies and clinical assessments were prospectively undertaken on six patients with BVVL secondary to riboflavin transporter deficiency type 2 (age range 10-21 years) at baseline and after 12 months of riboflavin (1000 mg daily) therapy. RESULTS: At baseline, depolarizing and hyperpolarizing threshold electrotonus was 'fanned out' and superexcitability was increased, while the resting current-threshold gradient and refractoriness were significantly reduced in BVVL patients when compared to controls. Mathematical modeling suggested that functional alterations of myelin underlay these findings with an increase in myelin permeability. Riboflavin therapy resulted in partial normalization of the axonal excitability findings, paralleled by maintenance of muscle strength. CONCLUSIONS: The present study established that abnormalities in myelin permeability at the paranode was a feature of BVVL and were partially normalized with riboflavin therapy. SIGNIFICANCE: This study reveals a novel pathophysiological process for motor nerve dysfunction in BVVL. It also indicates that nerve excitability studies may be further developed in larger cohorts as a potential biomarker to identify treatment response for BVVL patients.

The pharyngeal-cervical-brachial form of Guillain-Barré syndrome in childhood.

Variant forms of the Guillain-Barré syndrome are characterized by their localized or regional involvement of the peripheral and autonomic nerves. As there is no single clinical or serologic marker for Guillain-Barré syndrome, diagnosis of this condition is based upon consistent clinical, laboratory, and neurophysiologic findings, with exclusion of other conditions mimicking this disorder. Recognition of atypical cases enables anticipatory monitoring for disease complications and identifies therapeutic options for affected children. A regional variant with predominant facial, neck, and arm weakness without sensory loss has been reported in adults but only rarely described in childhood. This study reports clinical and neurophysiologic findings in two children with the pharyngeal-cervical-brachial form of Guillain-Barré syndrome. These are the youngest cases of this uncommon disorder reported to date.

Infectious and autoantibody-associated encephalitis: clinical features and long-term outcome.

BACKGROUND AND OBJECTIVES: Pediatric encephalitis has a wide range of etiologies, clinical presentations, and outcomes. This study seeks to classify and characterize infectious, immune-mediated/autoantibody-associated and unknown forms of encephalitis, including relative frequencies, clinical and radiologic phenotypes, and long-term outcome. METHODS: By using consensus definitions and a retrospective single-center cohort of 164 Australian children, we performed clinical and radiologic phenotyping blinded to etiology and outcomes, and we tested archived acute sera for autoantibodies to N-methyl-D-aspartate receptor, voltage-gated potassium channel complex, and other neuronal antigens. Through telephone interviews, we defined outcomes by using the Liverpool Outcome Score (for encephalitis). RESULTS: An infectious encephalitis occurred in 30%, infection-associated encephalopathy in 8%, immune-mediated/autoantibody-associated encephalitis in 34%, and unknown encephalitis in 28%. In descending order of frequency, the larger subgroups were acute disseminated encephalomyelitis (21%), enterovirus (12%), Mycoplasma pneumoniae (7%), N-methyl-D-aspartate receptor antibody (6%), herpes simplex virus (5%), and voltage-gated potassium channel complex antibody (4%). Movement disorders, psychiatric symptoms, agitation, speech dysfunction, cerebrospinal fluid oligoclonal bands, MRI limbic encephalitis, and clinical relapse were more common in patients with autoantibodies. An abnormal outcome occurred in 49% of patients after a median follow-up of 5.8 years. Herpes simplex virus and unknown forms had the worst outcomes. According to our multivariate analysis, an abnormal outcome was more common in patients with status epilepticus, magnetic resonance diffusion restriction, and ICU admission. CONCLUSIONS: We have defined clinical and radiologic phenotypes of infectious and immune-mediated/autoantibody-associated encephalitis. In this resource-rich cohort, immune-mediated/autoantibody-associated etiologies are common, and the recognition and treatment of these entities should be a clinical priority.

The 2q23.1 microdeletion syndrome: clinical and behavioural phenotype.

Six submicroscopic deletions comprising chromosome band 2q23.1 in patients with severe mental retardation (MR), short stature, microcephaly and epilepsy have been reported, suggesting that haploinsufficiency of one or more genes in the 2q23.1 region might be responsible for the common phenotypic features in these patients. In this study, we report the molecular and clinical characterisation of nine new 2q23.1 deletion patients and a clinical update on two previously reported patients. All patients were mentally retarded with pronounced speech delay and additional abnormalities including short stature, seizures, microcephaly and coarse facies. The majority of cases presented with stereotypic repetitive behaviour, a disturbed sleep pattern and a broad-based gait. These features led to the initial clinical impression of Angelman, Rett or Smith-Magenis syndromes in several patients. The overlapping 2q23.1 deletion region in all 15 patients comprises only one gene, namely, MBD5. Interestingly, MBD5 is a member of the methyl CpG-binding domain protein family, which also comprises MECP2, mutated in Rett's syndrome. Another gene in the 2q23.1 region, EPC2, was deleted in 12 patients who had a broader phenotype than those with a deletion of MBD5 only. EPC2 is a member of the polycomb protein family, involved in heterochromatin formation and might be involved in causing MR. Patients with a 2q23.1 microdeletion present with a variable phenotype and the diagnosis should be considered in mentally retarded children with coarse facies, seizures, disturbed sleeping patterns and additional specific behavioural problems.

High-dose riboflavin for migraine prophylaxis in children: a double-blind, randomized, placebo-controlled trial.

This is the first study to evaluate the efficacy of riboflavin for migraine prophylaxis in children. This was a randomized, double-blind study of riboflavin (200 mg daily) versus placebo in 48 children. The primary efficacy measure was the number of patients achieving a 50% or greater reduction in the number of migraine attacks per 4 weeks. Other outcome measures were the mean severity of migraine per day, mean duration of migraine, days with nausea or vomiting, analgesic use, and adverse effects. A 50% or greater reduction in headaches was seen in 14/21 patients in the placebo group and 12/27 patients in the riboflavin group (not significant P = .125). There were no differences between riboflavin and placebo for primary or secondary outcome variables. These results suggest that riboflavin is not an effective therapy for preventing migraine in children. A high placebo responder rate was seen, with implications for other studies of migraine in children.

Peripheral neuropathies of infancy.

Over a 33-year period, 260 patients (< 17 years of age; 119 males, 141 females) from New South Wales, Australia who had peripheral neuropathies confirmed by nerve biopsy, were studied. Of these, 50 infants presented with symptoms or signs of neuropathy under 1 year of age: including 24 patients with demyelinating neuropathies and 21 axonal neuropathies; a further five patients had spinal muscular atrophy with associated secondary sensory axonopathy. Nineteen infants had hereditary motor sensory neuropathy, of whom 13 had myelin protein mutations confirmed by molecular genetic studies. Peripheral neuropathy is not an unusual diagnosis in infancy. Awareness of this association will aid early diagnosis and prognosis as well as facilitate interventional patient management.